[Mlir-commits] [mlir] [memref] Support non-scalar copies in `reinterpret_cast` elision (PR #203873)

ioana ghiban llvmlistbot at llvm.org
Mon Jun 29 06:38:10 PDT 2026


https://github.com/ioghiban updated https://github.com/llvm/llvm-project/pull/203873

>From 5f862cac4e31c6a1481525fbf56f1abedfda06fe Mon Sep 17 00:00:00 2001
From: Ioana Ghiban <ioana.ghiban at arm.com>
Date: Fri, 12 Jun 2026 20:00:44 +0200
Subject: [PATCH 1/8] [memref] Support non-scalar copies in reinterpret_cast
 elision

---
 .../mlir/Dialect/MemRef/Transforms/Passes.td  |   3 +
 .../Dialect/MemRef/Transforms/CMakeLists.txt  |   1 +
 .../Transforms/ElideReinterpretCast.cpp       | 455 +++++++++++++-----
 .../MemRef/elide-reinterpret-cast.mlir        | 258 +++++++++-
 4 files changed, 577 insertions(+), 140 deletions(-)

diff --git a/mlir/include/mlir/Dialect/MemRef/Transforms/Passes.td b/mlir/include/mlir/Dialect/MemRef/Transforms/Passes.td
index 915667190a3d3..7b54be85db340 100644
--- a/mlir/include/mlir/Dialect/MemRef/Transforms/Passes.td
+++ b/mlir/include/mlir/Dialect/MemRef/Transforms/Passes.td
@@ -19,6 +19,9 @@ def ElideReinterpretCastPass : Pass<"memref-elide-reinterpret-cast"> {
     operations to obtain compatible shapes with equivalent ops that operate on
     compatible shapes directly. This simplifies conversion to EmitC.
 }];
+  let dependentDialects = [
+      "arith::ArithDialect", "memref::MemRefDialect", "scf::SCFDialect"
+  ];
 }
 
 def ExpandOpsPass : Pass<"memref-expand"> {
diff --git a/mlir/lib/Dialect/MemRef/Transforms/CMakeLists.txt b/mlir/lib/Dialect/MemRef/Transforms/CMakeLists.txt
index 1c5e07f89b338..c2ead38d644da 100644
--- a/mlir/lib/Dialect/MemRef/Transforms/CMakeLists.txt
+++ b/mlir/lib/Dialect/MemRef/Transforms/CMakeLists.txt
@@ -38,6 +38,7 @@ add_mlir_dialect_library(MLIRMemRefTransforms
   MLIRMemRefUtils
   MLIRNVGPUDialect
   MLIRPass
+  MLIRSCFDialect
   MLIRTensorDialect
   MLIRTransforms
   MLIRValueBoundsOpInterface
diff --git a/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp b/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
index 41dad1384da75..47aac6b64d092 100644
--- a/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
+++ b/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
@@ -11,10 +11,10 @@
 #include "mlir/Dialect/Arith/Utils/Utils.h"
 #include "mlir/Dialect/MemRef/IR/MemRef.h"
 #include "mlir/Dialect/MemRef/Transforms/Transforms.h"
+#include "mlir/Dialect/SCF/IR/SCF.h"
 #include "mlir/IR/Matchers.h"
 #include "mlir/IR/TypeUtilities.h"
 #include "mlir/Transforms/DialectConversion.h"
-#include "llvm/ADT/Repeated.h"
 #include <cassert>
 #include <optional>
 
@@ -29,128 +29,268 @@ using namespace mlir;
 
 namespace {
 
-/// Returns true if `rc` represents a scalar view (all sizes == 1)
-/// into a memref that has exactly one non-unit dimension located at
-/// either the first or last position (i.e. a "row" or "column").
+static std::optional<SmallVector<int64_t>> getIdentityStrides(MemRefType type) {
+  if (!type.getLayout().isIdentity() || !type.hasStaticShape())
+    return std::nullopt;
+
+  SmallVector<int64_t> strides(type.getRank(), 1);
+  int64_t stride = 1;
+  for (int64_t dim = type.getRank() - 1; dim >= 0; --dim) {
+    strides[dim] = stride;
+    stride *= type.getDimSize(dim);
+  }
+  return strides;
+}
+
+static std::optional<unsigned>
+findBaseDimForViewStride(MemRefType baseType, ArrayRef<int64_t> baseStrides,
+                         ArrayRef<bool> usedBaseDims, int64_t viewStride,
+                         int64_t viewSize) {
+  std::optional<unsigned> fallback;
+  for (auto [idx, stride] : llvm::enumerate(baseStrides)) {
+    if (usedBaseDims[idx] || stride != viewStride ||
+        baseType.getDimSize(idx) < viewSize)
+      continue;
+
+    // Prefer an exact shape match. Otherwise, use the first dimension large
+    // enough to contain the copied logical vector.
+    if (baseType.getDimSize(idx) == viewSize)
+      return idx;
+    if (!fallback)
+      fallback = idx;
+  }
+  return fallback;
+}
+
+static std::optional<SmallVector<int64_t>>
+delinearizeStaticOffset(int64_t offset, MemRefType baseType,
+                        ArrayRef<int64_t> baseStrides) {
+  if (offset < 0)
+    return std::nullopt;
+
+  SmallVector<int64_t> indices(baseType.getRank(), 0);
+  int64_t remainder = offset;
+  for (auto [idx, stride] : llvm::enumerate(baseStrides)) {
+    indices[idx] = remainder / stride;
+    if (indices[idx] >= baseType.getDimSize(idx))
+      return std::nullopt;
+    remainder %= stride;
+  }
+
+  if (remainder != 0)
+    return std::nullopt;
+  return indices;
+}
+
+static std::optional<unsigned> getSingleNonUnitDim(MemRefType type) {
+  if (!type.hasStaticShape() || type.getRank() == 0)
+    return std::nullopt;
+
+  std::optional<unsigned> nonUnitDim;
+  for (auto [idx, dim] : llvm::enumerate(type.getShape())) {
+    if (dim == 1)
+      continue;
+    if (nonUnitDim)
+      return std::nullopt;
+    nonUnitDim = idx;
+  }
+  return nonUnitDim;
+}
+
+struct CopyLoopDimInfo {
+  unsigned viewDim;
+  unsigned dstLoopDim;
+  int64_t loopSize;
+};
+
+struct CopyToLoadStoreInfo {
+  SmallVector<CopyLoopDimInfo> loopDims;
+  SmallVector<int64_t> staticOffsetIndices;
+  std::optional<unsigned> dynamicOffsetDim;
+};
+
+/// Builds the index mapping needed to replace a copy into a reinterpret_cast
+/// view with scalar stores into the reinterpret_cast base.
 ///
-/// Examples that return true:
+/// Checklist:
+/// - The copy destination must be a `memref.reinterpret_cast`.
+/// - The copy source, reinterpret_cast source, and reinterpret_cast result must
+///   be ranked memrefs with static shapes.
+/// - The reinterpret_cast source/result ranks must match.
+/// - The reinterpret_cast source must have static identity layout.
+/// - Each non-unit copied view dimension must have a static stride that maps to
+///   an identity-layout base dimension.
+/// - Static offsets, dynamic only in scalar or effectively-1D copies
+///   where the offset can be used directly as one base index.
 ///
-///   // Row-major slice (last dim is non-unit)
-///   memref.reinterpret_cast %buff to offset: [%off],
-///     sizes: [1, 1, 1], strides: [1, 1, 1]
-///     : memref<1x1x8xi32> to memref<1x1x1xi32>
+/// Examples that return true:
 ///
-///   // Column-major slice (first dim is non-unit)
-///   memref.reinterpret_cast %buff to offset: [%off],
-///     sizes: [1, 1], strides: [1, 1]
-///     : memref<2x1xf32> to memref<1x1xf32>
+///   // Scalar-shaped copy. There are no copied non-unit dimensions, so
+///   // dynamic strides in the scalar view do not affect index mapping.
+///   copy memref<1x...x1xf32>
+///     to reinterpret_cast memref<base-shape>
+///       to memref<1x...x1xf32, strided<[?, ..., ?], offset: ?>>
 ///
-///   // Random strides
-///   memref.reinterpret_cast %buff to offset: [%off],
-///     sizes: [1, 1], strides: [10, 100]
-///     : memref<2x1xf32, strided<[10, 100]>>
-///         to memref<1x1xf32>
+///   // Effectively-1D copy. The single non-unit view dimension is mapped to
+///   // an identity-layout base dimension by its static stride.
+///   copy memref<1x...xNx...x1xf32>
+///     to reinterpret_cast memref<base-shape>
+///       to memref<1x...xNx...x1xf32, strided<[..., S, ...]>>
 ///
-///   // Rank-1 case
-///   memref.reinterpret_cast %buf to offset: [%off],
-///     sizes: [1], strides: [1]
-///     : memref<8xi32> to memref<1xi32>
+///   // Multidimensional copy with static offset. Each non-unit view dimension
+///   // is mapped independently by its static stride.
+///   copy memref<1x...xNx...xKx...x1xf32>
+///     to reinterpret_cast memref<base-shape>
+///       to memref<1x...xNx...xKx...x1xf32,
+///                 strided<[..., S0, ..., S1, ...], offset: O>>
 ///
 /// Examples that return false:
 ///
-///   // More non-unit dims
-///   memref.reinterpret_cast %buff to offset: [%off],
-///     sizes: [1, 1, 1], strides: [1, 1, 1]
-///     : memref<1x2x8xi32> to memref<1x1x1xi32>
+///   // Dynamic stride on a copied view dimension.
+///   copy memref<1xNxf32>
+///     to reinterpret_cast memref<1xNxMxf32>
+///       to memref<1xNxf32, strided<[?, ?]>>
 ///
-///   // View is not scalar (size != 1)
-///   memref.reinterpret_cast %buff to offset: [%off],
-///     sizes: [2, 1], strides: [1, 1]
-///     : memref<1x2xf32> to memref<2x1xf32>
-///
-///   // Base has non-identity layout
-///   %buff = memref.alloc() : memref<1x2xf32, strided<[1, 3]>>
-///   memref.reinterpret_cast %buff to offset: [%off],
-///     sizes: [1, 1], strides: [1, 1]
-///     : memref<1x2xf32, strided<[1, 3]>> to memref<1x1xf32>
-static bool isScalarSlice(memref::ReinterpretCastOp rc) {
-  auto rcInputTy = dyn_cast<MemRefType>(rc.getSource().getType());
-  auto rcOutputTy = dyn_cast<MemRefType>(rc.getType());
-
-  // Reject strided base - logic for computing linear idx is TODO
-  if (!rcInputTy.getLayout().isIdentity())
-    return false;
+///   // Multidimensional copy with dynamic linear offset.
+///   copy memref<1xNxKxf32>
+///     to reinterpret_cast memref<1xNxMxf32>
+///       to memref<1xNxKxf32, strided<[N*M, M, 1], offset: ?>>
+static std::optional<CopyToLoadStoreInfo>
+getCopyToLoadStoreInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
+  MemRefType srcType = dyn_cast<MemRefType>(op.getSource().getType());
+  MemRefType baseType = dyn_cast<MemRefType>(rc.getSource().getType());
+  MemRefType viewType = dyn_cast<MemRefType>(rc.getType());
+  // TODO: Support unranked copy sources or reinterpret_cast sources.
+  if (!srcType || !baseType || !viewType)
+    return std::nullopt;
 
-  // Reject non-matching ranks
-  unsigned srcRank = rcInputTy.getRank();
-  if (srcRank != rcOutputTy.getRank())
-    return false;
+  // TODO: Support rank-changing reinterpret_casts by converting the
+  // destination view indices to base indices. For example, a copy to a
+  // memref<2x3xf32> view of memref<6xf32> needs to linearize the view indices
+  // as `i * 3 + j`, then combine that with the reinterpret_cast offset before
+  // indexing the rank-1 base memref.
+  if (baseType.getRank() != viewType.getRank())
+    return std::nullopt;
 
-  ArrayRef<int64_t> sizes = rc.getStaticSizes();
+  // TODO: Support dynamic shapes with mixed size operands as loop bounds.
+  if (!(srcType.hasStaticShape() && baseType.hasStaticShape() &&
+        viewType.hasStaticShape()))
+    return std::nullopt;
 
-  // View must be scalar: memref<1x...x1>
-  if (!llvm::all_of(rcOutputTy.getShape(),
-                    [](int64_t dim) { return dim == 1; }))
-    return false;
+  assert(srcType.getShape() == viewType.getShape() &&
+         "copy source and destination are expected to have the same shape");
 
-  // Sizes must all be statically 1
-  if (!llvm::all_of(sizes, [](int64_t size) {
-        return !ShapedType::isDynamic(size) && size == 1;
-      }))
-    return false;
+  // Store indices are formed in the reinterpret_cast source layout.
+  std::optional<SmallVector<int64_t>> baseStrides =
+      getIdentityStrides(baseType);
+  // TODO: Support non-identity reinterpret_cast source layouts by using the
+  // source layout strides as base strides.
+  if (!baseStrides)
+    return std::nullopt;
 
-  // Rank-1 special case
-  if (srcRank == 1) {
-    // Reject non-scalar output
-    if (rcOutputTy.getDimSize(0) > 1)
-      return false;
+  CopyToLoadStoreInfo info;
+  SmallVector<bool> usedBaseDims(baseType.getRank(), false);
+
+  // Non-unit view dimensions become loop dimensions in the scalar rewrite.
+  for (auto [viewDim, viewSize] : llvm::enumerate(viewType.getShape())) {
+    if (viewSize == 1)
+      continue;
+
+    // TODO: Support dynamic strides on copied view dimensions.
+    if (ShapedType::isDynamic(rc.getStaticStrides()[viewDim]))
+      return std::nullopt;
+
+    std::optional<unsigned> dstLoopDim =
+        findBaseDimForViewStride(baseType, *baseStrides, usedBaseDims,
+                                 rc.getStaticStrides()[viewDim], viewSize);
+    assert(dstLoopDim &&
+           "static reinterpret_cast stride must map to an identity base "
+           "dimension");
+
+    usedBaseDims[*dstLoopDim] = true;
+    info.loopDims.push_back(
+        CopyLoopDimInfo{static_cast<unsigned>(viewDim), *dstLoopDim, viewSize});
+  }
+
+  ArrayRef<int64_t> staticOffsets = rc.getStaticOffsets();
+  assert(staticOffsets.size() == 1 && "Expecting single offset");
+  if (!ShapedType::isDynamic(staticOffsets[0])) {
+    // Static offsets are converted to base indices.
+    std::optional<SmallVector<int64_t>> offsetIndices =
+        delinearizeStaticOffset(staticOffsets[0], baseType, *baseStrides);
+    assert(offsetIndices &&
+           "static reinterpret_cast offset must delinearize to in-bounds base "
+           "indices");
+
+    for (const CopyLoopDimInfo &loopDim : info.loopDims) {
+      assert((*offsetIndices)[loopDim.dstLoopDim] + loopDim.loopSize <=
+                 baseType.getDimSize(loopDim.dstLoopDim) &&
+             "reinterpret_cast metadata describes an invalid accessible "
+             "region");
+    }
+    info.staticOffsetIndices = std::move(*offsetIndices);
+    return info;
   }
 
-  int nonUnitCount =
-      std::count_if(rcInputTy.getShape().begin(), rcInputTy.getShape().end(),
-                    [](int dim) { return dim != 1; });
-  return nonUnitCount == 1;
+  // Dynamic offsets are kept only when they can be used as a single base index.
+  // TODO: Support multidimensional dynamic offsets with div/mod
+  // delinearization.
+  if (info.loopDims.size() > 1)
+    return std::nullopt;
+
+  if (info.loopDims.empty()) {
+    // TODO: Support scalar dynamic offsets into bases with multiple non-unit
+    // dimensions, and all-unit bases with a provably zero offset.
+    std::optional<unsigned> nonUnitDim = getSingleNonUnitDim(baseType);
+    if (!nonUnitDim)
+      return std::nullopt;
+
+    info.dynamicOffsetDim = *nonUnitDim;
+    return info;
+  }
+
+  unsigned dstLoopDim = info.loopDims.front().dstLoopDim;
+  info.dynamicOffsetDim =
+      (*baseStrides)[dstLoopDim] == 1 ? dstLoopDim : baseStrides->size() - 1;
+  return info;
 }
 
-/// Rewrites `memref.copy` of a 1-element MemRef as a scalar load-store pair
+/// Rewrites supported copy operations through `memref.reinterpret_cast` to
+/// scalar load/store operations.
 ///
-/// The pattern matches a reinterpret_cast that creates a scalar view
-/// (`sizes = [1, ..., 1]`) into a memref with a single non-unit dimension.
-/// Since the view contains only one element, the accessed address is
-/// determined solely by the base pointer and the offset.
+///   // BEFORE (scalar copy)
+///   %view = memref.reinterpret_cast %dst
+///     to offset: [O], sizes: [1, ..., 1], strides: [...]
+///   memref.copy %src, %view
 ///
-/// Two layouts are supported:
-///   * row-major slice  (stride pattern [N, ..., 1])
-///   * column-major slice (stride pattern [1, ..., N])
+///   // AFTER
+///   %v = memref.load %src[0, ..., 0]
+///   memref.store %v, %dst[delinearized(O)]
 ///
-/// BEFORE (row-major slice)
-///   %view = memref.reinterpret_cast %base
-///     to offset: [%off], sizes: [1, ..., 1], strides: [N, ..., 1]
-///       : memref<1x...xNxf32>
-///         to memref<1x...x1xf32, strided<[N, ..., 1], offset: ?>>
+///   // BEFORE (effectively-1D copy)
+///   %view = memref.reinterpret_cast %dst
+///     to offset: [O], sizes: [1, N, 1], strides: [...]
 ///   memref.copy %src, %view
-///     : memref<1x...x1xf32>
-///       to memref<1x...x1xf32, strided<[N, ..., 1], offset: ?>>
 ///
-/// AFTER
-///   %c0 = arith.constant 0 : index
-///   %v  = memref.load %src[%c0, ..., %c0] : memref<1x...x1xf32>
-///   memref.store %v, %base[%c0, ..., %off] : memref<1x...xNxf32>
+///   // AFTER
+///   scf.for %i = 0 to N step 1 {
+///     %v = memref.load %src[0, %i, 0]
+///     memref.store %v, %dst[delinearized(O) + mapped(%i)]
+///   }
 ///
-/// BEFORE (column-major slice)
-///   %view = memref.reinterpret_cast %base
-///     to offset: [%off], sizes: [1, ..., 1], strides: [1, ..., N]
-///       : memref<Nx...x1xf32>
-///         to memref<1x...x1xf32, strided<[1, ..., N], offset: ?>>
+///   // BEFORE (multidimensional copy with static offset)
+///   %view = memref.reinterpret_cast %dst
+///     to offset: [O], sizes: [1, N, K], strides: [...]
 ///   memref.copy %src, %view
-///     : memref<1x...x1xf32>
-///       to memref<1x...x1xf32, strided<[1, ..., N], offset: ?>>
 ///
-/// AFTER
-///   %c0 = arith.constant 0 : index
-///   %v  = memref.load %src[%c0, ..., %c0] : memref<1x...x1xf32>
-///   memref.store %v, %base[%off, ..., %c0] : memref<Nx...x1xf32>
-struct CopyToScalarLoadAndStore : public OpRewritePattern<memref::CopyOp> {
+///   // AFTER
+///   scf.for %i = 0 to N step 1 {
+///     scf.for %j = 0 to K step 1 {
+///       %v = memref.load %src[0, %i, %j]
+///       memref.store %v, %dst[delinearized(O) + mapped(%i, %j)]
+///     }
+///   }
+struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
 public:
   using OpRewritePattern::OpRewritePattern;
 
@@ -162,38 +302,112 @@ struct CopyToScalarLoadAndStore : public OpRewritePattern<memref::CopyOp> {
       return rewriter.notifyMatchFailure(
           op, "target is not a memref.reinterpret_cast");
 
-    if (!isScalarSlice(rc))
+    std::optional<CopyToLoadStoreInfo> copyInfo =
+        getCopyToLoadStoreInfo(op, rc);
+    if (!copyInfo)
       return rewriter.notifyMatchFailure(
-          op, "reinterpret_cast does not match scalar slice");
+          op, "reinterpret_cast does not match scalar or loop copy region");
 
     Location loc = op.getLoc();
-
     Value src = op.getSource();
     Value dst = rc.getSource();
 
-    auto dstType = cast<MemRefType>(dst.getType());
-    unsigned dstRank = dstType.getRank();
+    MemRefType srcType = cast<MemRefType>(src.getType());
+    MemRefType dstType = cast<MemRefType>(dst.getType());
 
     Value zero = arith::ConstantIndexOp::create(rewriter, loc, 0);
+    Value one;
+    // Reuse common index constants across bounds, steps, and static offsets.
+    // Keep `%c1` lazy so scalar copies without loops do not create an unused
+    // loop-step constant.
+    auto getOrCreateIndexConstant = [&](int64_t value) -> Value {
+      if (value == 0)
+        return zero;
+      if (value == 1) {
+        if (!one)
+          one = arith::ConstantIndexOp::create(rewriter, loc, 1);
+        return one;
+      }
+      return arith::ConstantIndexOp::create(rewriter, loc, value);
+    };
+
+    // Materialize all loop bounds before building the loop nest. Otherwise an
+    // inner-loop bound may be created inside an outer loop body.
+    SmallVector<Value> upperBounds;
+    upperBounds.reserve(copyInfo->loopDims.size());
+    for (const CopyLoopDimInfo &loopDim : copyInfo->loopDims)
+      upperBounds.push_back(getOrCreateIndexConstant(loopDim.loopSize));
+
+    SmallVector<Value> baseStoreIndices(dstType.getRank(), zero);
+    // Static offsets were already delinearized into base indices. Materialize
+    // the non-zero starting indices before creating loop bodies.
+    if (!copyInfo->staticOffsetIndices.empty()) {
+      for (auto [idx, offset] :
+           llvm::enumerate(copyInfo->staticOffsetIndices)) {
+        if (offset == 0)
+          continue;
+        baseStoreIndices[idx] = getOrCreateIndexConstant(offset);
+      }
+    } else if (copyInfo->dynamicOffsetDim) {
+      // Supported dynamic offsets are used directly in exactly one base
+      // dimension selected by getCopyToLoadStoreInfo.
+      SmallVector<OpFoldResult> offsets = rc.getMixedOffsets();
+      assert(offsets.size() == 1 && "Expecting single offset");
+      baseStoreIndices[*copyInfo->dynamicOffsetDim] =
+          getValueOrCreateConstantIndexOp(rewriter, loc, offsets[0]);
+    }
 
-    auto srcType = cast<MemRefType>(src.getType());
-    Repeated<Value> loadIndices(srcType.getRank(), zero);
-    auto offsets = rc.getMixedOffsets();
-    assert(offsets.size() == 1 && "Expecting single offset");
-    OpFoldResult offset = offsets[0];
-    Value storeOffset = getValueOrCreateConstantIndexOp(rewriter, loc, offset);
-    unsigned offsetDim = dstType.getDimSize(0) == 1 ? dstRank - 1 : 0;
-    SmallVector<Value> storeIndices(dstRank, zero);
-    storeIndices[offsetDim] = storeOffset;
-    // If the only user of `rc` is the current Op (which is about to be erased),
-    // we can safely erase it.
-    if (rcOutput.hasOneUse())
-      rewriter.eraseOp(rc);
+    // Scope for OpBuilder::InsertionGuard.
+    {
+      OpBuilder::InsertionGuard guard(rewriter);
+      Value step;
+      if (!upperBounds.empty())
+        step = getOrCreateIndexConstant(1);
+
+      SmallVector<Value> loopIvs;
+      loopIvs.reserve(copyInfo->loopDims.size());
+
+      // Build one nested loop per non-unit copied view dimension.
+      for (Value upperBound : upperBounds) {
+        scf::ForOp loop =
+            scf::ForOp::create(rewriter, loc, zero, upperBound, step);
+        loopIvs.push_back(loop.getInductionVar());
+        rewriter.setInsertionPointToStart(loop.getBody());
+      }
+
+      // Load indices are zero except for copied view dimensions, which use the
+      // corresponding loop induction variables.
+      SmallVector<Value> loadIndices(srcType.getRank(), zero);
+      unsigned loopIndex = 0;
+      for (const CopyLoopDimInfo &loopDim : copyInfo->loopDims)
+        loadIndices[loopDim.viewDim] = loopIvs[loopIndex++];
+
+      // Store indices start from the offset-derived base indices. Add each loop
+      // IV to the mapped base dimension.
+      SmallVector<Value> storeIndices(baseStoreIndices);
+      loopIndex = 0;
+      for (const CopyLoopDimInfo &loopDim : copyInfo->loopDims) {
+        Value iv = loopIvs[loopIndex++];
+        if (storeIndices[loopDim.dstLoopDim] == zero) {
+          storeIndices[loopDim.dstLoopDim] = iv;
+        } else {
+          storeIndices[loopDim.dstLoopDim] = arith::AddIOp::create(
+              rewriter, loc, storeIndices[loopDim.dstLoopDim], iv);
+        }
+      }
 
-    Value val = memref::LoadOp::create(rewriter, loc, src, loadIndices);
-    memref::StoreOp::create(rewriter, loc, val, dst, storeIndices);
+      // Emit the scalar load/store at the innermost loop body, or directly at
+      // the original copy location for scalar copies.
+      Value val = memref::LoadOp::create(rewriter, loc, src, loadIndices);
+      memref::StoreOp::create(rewriter, loc, val, dst, storeIndices);
+    }
 
+    // If the only user of `rc` is the current Op (which is about to be erased),
+    // we can safely erase it.
+    bool eraseRc = rcOutput.hasOneUse();
     rewriter.eraseOp(op);
+    if (eraseRc)
+      rewriter.eraseOp(rc);
     return success();
   }
 };
@@ -466,7 +680,7 @@ struct ElideReinterpretCastPass
       auto rc = op.getTarget().getDefiningOp<memref::ReinterpretCastOp>();
       if (!rc)
         return true;
-      return !isScalarSlice(rc);
+      return !getCopyToLoadStoreInfo(op, rc);
     });
     target.addDynamicallyLegalOp<memref::LoadOp>([](memref::LoadOp op) {
       auto rc = op.getMemRef().getDefiningOp<memref::ReinterpretCastOp>();
@@ -474,7 +688,8 @@ struct ElideReinterpretCastPass
         return true;
       return !isPureRankExpansionOrCollapsingRC(rc);
     });
-    target.addLegalDialect<arith::ArithDialect, memref::MemRefDialect>();
+    target.addLegalDialect<arith::ArithDialect, memref::MemRefDialect,
+                           scf::SCFDialect>();
     if (failed(applyPartialConversion(getOperation(), target,
                                       std::move(patterns))))
       signalPassFailure();
@@ -485,6 +700,6 @@ struct ElideReinterpretCastPass
 
 void mlir::memref::populateElideReinterpretCastPatterns(
     RewritePatternSet &patterns) {
-  patterns.add<CopyToScalarLoadAndStore, RewriteLoadFromReinterpretCast>(
+  patterns.add<CopyToLoadAndStore, RewriteLoadFromReinterpretCast>(
       patterns.getContext());
 }
diff --git a/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir b/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
index 61b6d480ce7a0..90431fb507c1e 100644
--- a/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
+++ b/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
@@ -19,9 +19,8 @@ func.func private @concat_zero_offset(%src : memref<1x1xf32>,
   /// Ensure copy was replaced
   // CHECK-NOT:  memref.copy
   // CHECK:      %[[C0:.*]] = arith.constant 0 : index
-  // CHECK:      %[[C0_0:.*]] = arith.constant 0 : index
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]]] : memref<1x1xf32>
-  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0_0]]] : memref<1x108xf32>
+  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]]] : memref<1x108xf32>
   memref.copy %src, %reinterpret_cast
     : memref<1x1xf32> to memref<1x1xf32>
   return
@@ -85,14 +84,14 @@ func.func private @concat_strided(%src : memref<1x1xf32>,
 
   // CHECK-NOT:  memref.copy
   // CHECK:      %[[C0:.*]] = arith.constant 0 : index
-  // CHECK:      %[[C0_0:.*]] = arith.constant 0 : index
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]]] : memref<1x1xf32>
-  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0_0]]] : memref<1x108xf32>
+  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]]] : memref<1x108xf32>
   memref.copy %src, %reinterpret_cast
     : memref<1x1xf32> to memref<1x1xf32, strided<[107, 2]>>
   return
 }
 
+// Dynamic strides are irrelevant because all view indices are zero.
 // CHECK-LABEL: func.func private @concat_dynamic_stride(
 // CHECK-SAME:   %[[STR0:[A-Za-z][A-Za-z0-9-]*]]: index
 // CHECK-SAME:   %[[STR1:[A-Za-z][A-Za-z0-9-]*]]: index
@@ -108,10 +107,9 @@ func.func private @concat_dynamic_stride(%stride0: index,
 
   // CHECK-NOT:  memref.copy
   // CHECK:      %[[C0:.*]] = arith.constant 0 : index
-  // CHECK:      %[[C0_0:.*]] = arith.constant 0 : index
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]]] : memref<1x1xf32>
   /// Dynamic offset used in store
-  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0_0]]] : memref<1x108xf32>
+  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]]] : memref<1x108xf32>
   memref.copy %src, %reinterpret_cast
     : memref<1x1xf32>
       to memref<1x1xf32, strided<[?, ?]>>
@@ -129,9 +127,8 @@ func.func private @concat_rank1(%src : memref<1xf32>, %dst : memref<108xf32>) {
 
   // CHECK-NOT:  memref.copy
   // CHECK:      %[[C0:.*]] = arith.constant 0 : index
-  // CHECK:      %[[C0_0:.*]] = arith.constant 0 : index
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]]] : memref<1xf32>
-  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0_0]]] : memref<108xf32>
+  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]]] : memref<108xf32>
   memref.copy %src, %reinterpret_cast
     : memref<1xf32> to memref<1xf32>
   return
@@ -149,14 +146,165 @@ func.func private @concat_rank3(%src : memref<1x1x1xf32>,
 
   // CHECK-NOT:  memref.copy
   // CHECK:      %[[C0:.*]] = arith.constant 0 : index
-  // CHECK:      %[[C0_0:.*]] = arith.constant 0 : index
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]], %[[C0]]] : memref<1x1x1xf32>
-  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]], %[[C0_0]]] : memref<1x1x108xf32>
+  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]], %[[C0]]] : memref<1x1x108xf32>
   memref.copy %src, %reinterpret_cast
     : memref<1x1x1xf32> to memref<1x1x1xf32>
   return
 }
 
+// CHECK-LABEL: func.func private @concat_0d(
+// CHECK-SAME:   %[[SRC:.*]]: memref<1x1x1xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
+func.func private @concat_0d(
+  %src : memref<1x1x1xf32>, %dst : memref<1x33x42xf32>) {
+  // CHECK-NOT:  memref.reinterpret_cast
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [0], sizes: [1, 1, 1], strides: [1, 1, 1]
+    : memref<1x33x42xf32>
+      to memref<1x1x1xf32>
+  // CHECK-NOT:  memref.copy
+  // CHECK:      %[[C0:.*]] = arith.constant 0 : index
+  // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]], %[[C0]]] : memref<1x1x1xf32>
+  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]], %[[C0]]] : memref<1x33x42xf32>
+  memref.copy %src, %reinterpret_cast
+    : memref<1x1x1xf32> to memref<1x1x1xf32>
+  return
+}
+
+// CHECK-LABEL: func.func private @concat_1d_vector_zero_offset(
+// CHECK-SAME:   %[[SRC:.*]]: memref<1x33x1xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
+func.func private @concat_1d_vector_zero_offset(
+  %src : memref<1x33x1xf32>, %dst : memref<1x33x42xf32>) {
+  // CHECK-NOT:  memref.reinterpret_cast
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [0], sizes: [1, 33, 1], strides: [1386, 42, 1]
+    : memref<1x33x42xf32>
+      to memref<1x33x1xf32, strided<[1386, 42, 1]>>
+
+  // CHECK-NOT:  memref.copy
+  // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
+  // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
+  // CHECK-DAG:  %[[C33:.*]] = arith.constant 33 : index
+  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C33]] step %[[C1]] {
+  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x33x1xf32>
+  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x33x42xf32>
+  // CHECK:      }
+  memref.copy %src, %reinterpret_cast
+    : memref<1x33x1xf32>
+      to memref<1x33x1xf32, strided<[1386, 42, 1]>>
+  return
+}
+
+// CHECK-LABEL: func.func private @concat_1d_vector_nonzero_offset(
+// CHECK-SAME:   %[[SRC:.*]]: memref<1x33x1xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
+func.func private @concat_1d_vector_nonzero_offset(
+  %src : memref<1x33x1xf32>, %dst : memref<1x33x42xf32>) {
+  // CHECK-NOT:  memref.reinterpret_cast
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [41], sizes: [1, 33, 1], strides: [1386, 42, 1]
+    : memref<1x33x42xf32>
+      to memref<1x33x1xf32, strided<[1386, 42, 1], offset: 41>>
+
+  // CHECK-NOT:  memref.copy
+  // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
+  // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
+  // CHECK-DAG:  %[[C33:.*]] = arith.constant 33 : index
+  // CHECK-DAG:  %[[C41:.*]] = arith.constant 41 : index
+  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C33]] step %[[C1]] {
+  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x33x1xf32>
+  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[C41]]] : memref<1x33x42xf32>
+  // CHECK:      }
+  memref.copy %src, %reinterpret_cast
+    : memref<1x33x1xf32>
+      to memref<1x33x1xf32, strided<[1386, 42, 1], offset: 41>>
+  return
+}
+
+// CHECK-LABEL: func.func private @concat_1d_vector_dynamic_offset_same_dim(
+// CHECK-SAME:   %[[OFF:.*]]: index
+// CHECK-SAME:   %[[SRC:.*]]: memref<4xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<42xf32>
+func.func private @concat_1d_vector_dynamic_offset_same_dim(
+  %offset : index, %src : memref<4xf32>, %dst : memref<42xf32>) {
+  // CHECK-NOT:  memref.reinterpret_cast
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [%offset], sizes: [4], strides: [1]
+    : memref<42xf32> to memref<4xf32, strided<[1], offset: ?>>
+
+  // CHECK-NOT:  memref.copy
+  // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
+  // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
+  // CHECK-DAG:  %[[C4:.*]] = arith.constant 4 : index
+  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C4]] step %[[C1]] {
+  // CHECK:        %[[DST_IDX:.*]] = arith.addi %[[OFF]], %[[IDX]] : index
+  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[IDX]]] : memref<4xf32>
+  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[DST_IDX]]] : memref<42xf32>
+  // CHECK:      }
+  memref.copy %src, %reinterpret_cast
+    : memref<4xf32> to memref<4xf32, strided<[1], offset: ?>>
+  return
+}
+
+// CHECK-LABEL: func.func private @concat_1d_vector_dynamic_offset_separate_dim(
+// CHECK-SAME:   %[[OFF:.*]]: index
+// CHECK-SAME:   %[[SRC:.*]]: memref<1x33x1xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
+func.func private @concat_1d_vector_dynamic_offset_separate_dim(
+  %offset : index, %src : memref<1x33x1xf32>,
+  %dst : memref<1x33x42xf32>) {
+  // CHECK-NOT:  memref.reinterpret_cast
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [%offset], sizes: [1, 33, 1], strides: [1386, 42, 1]
+    : memref<1x33x42xf32>
+      to memref<1x33x1xf32, strided<[1386, 42, 1], offset: ?>>
+
+  // CHECK-NOT:  memref.copy
+  // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
+  // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
+  // CHECK-DAG:  %[[C33:.*]] = arith.constant 33 : index
+  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C33]] step %[[C1]] {
+  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x33x1xf32>
+  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[OFF]]] : memref<1x33x42xf32>
+  // CHECK:      }
+  memref.copy %src, %reinterpret_cast
+    : memref<1x33x1xf32>
+      to memref<1x33x1xf32, strided<[1386, 42, 1], offset: ?>>
+  return
+}
+
+// CHECK-LABEL: func.func private @concat_2d_vector_offset(
+// CHECK-SAME:   %[[SRC:.*]]: memref<1x33x4xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
+func.func private @concat_2d_vector_offset(
+  %src : memref<1x33x4xf32>, %dst : memref<1x33x42xf32>) {
+  // CHECK-NOT:  memref.reinterpret_cast
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [16], sizes: [1, 33, 4], strides: [1386, 42, 1]
+    : memref<1x33x42xf32>
+      to memref<1x33x4xf32, strided<[1386, 42, 1], offset: 16>>
+
+  // CHECK-NOT:  memref.copy
+  // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
+  // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
+  // CHECK-DAG:  %[[C33:.*]] = arith.constant 33 : index
+  // CHECK-DAG:  %[[C4:.*]] = arith.constant 4 : index
+  // CHECK-DAG:  %[[C16:.*]] = arith.constant 16 : index
+  // CHECK:      scf.for %[[IDX0:.*]] = %[[C0]] to %[[C33]] step %[[C1]] {
+  // CHECK:        scf.for %[[IDX1:.*]] = %[[C0]] to %[[C4]] step %[[C1]] {
+  // CHECK:          %[[DST_IDX:.*]] = arith.addi %[[C16]], %[[IDX1]] : index
+  // CHECK:          %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX0]], %[[IDX1]]] : memref<1x33x4xf32>
+  // CHECK:          memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX0]], %[[DST_IDX]]] : memref<1x33x42xf32>
+  // CHECK:        }
+  // CHECK:      }
+  memref.copy %src, %reinterpret_cast
+    : memref<1x33x4xf32>
+      to memref<1x33x4xf32, strided<[1386, 42, 1], offset: 16>>
+  return
+}
+
 //===----------------------------------------------------------------------===//
 // Negative tests (must NOT rewrite)
 //===----------------------------------------------------------------------===//
@@ -179,8 +327,8 @@ func.func private @negative_concat_strided_base(%src: memref<1x1xf32>,
   return
 }
 
-// CHECK-LABEL: func.func private @negative_rank_change(
-func.func private @negative_rank_change(%src : memref<2x3xf32>,
+// CHECK-LABEL: func.func private @negative_concat_rank_change(
+func.func private @negative_concat_rank_change(%src : memref<2x3xf32>,
   %dst : memref<6xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -195,19 +343,90 @@ func.func private @negative_rank_change(%src : memref<2x3xf32>,
   return
 }
 
-// CHECK-LABEL: func.func private @negative_concat_multiple_non_unit_dims(
-func.func private @negative_concat_multiple_non_unit_dims(
-  %src : memref<1x1xf32>, %dst : memref<2x108xf32>) {
+// CHECK-LABEL: func.func private @negative_concat_dynamic_copy_source_shape(
+func.func private @negative_concat_dynamic_copy_source_shape(%src : memref<?xf32>,
+  %dst : memref<4xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
   %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [0], sizes: [1, 1], strides: [1, 1]
-    : memref<2x108xf32>
-      to memref<1x1xf32>
+    to offset: [0], sizes: [4], strides: [1]
+    : memref<4xf32> to memref<4xf32>
+
   // CHECK:      memref.copy %arg0, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
   memref.copy %src, %reinterpret_cast
-    : memref<1x1xf32> to memref<1x1xf32>
+    : memref<?xf32> to memref<4xf32>
+  return
+}
+
+// CHECK-LABEL: func.func private @negative_concat_dynamic_rc_shapes(
+func.func private @negative_concat_dynamic_rc_shapes(%dim : index,
+  %src : memref<4xf32>, %dst : memref<?xf32>) {
+  // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [0], sizes: [%dim], strides: [1]
+    : memref<?xf32> to memref<?xf32, strided<[1]>>
+
+  // CHECK:      memref.copy %arg1, %reinterpret_cast
+  // CHECK-NOT:  memref.load
+  // CHECK-NOT:  memref.store
+  memref.copy %src, %reinterpret_cast
+    : memref<4xf32> to memref<?xf32, strided<[1]>>
+  return
+}
+
+// CHECK-LABEL: func.func private @negative_concat_dynamic_offset_multi_dim_base(
+func.func private @negative_concat_dynamic_offset_multi_dim_base(
+  %offset : index, %src : memref<1x1xf32>, %dst : memref<4x8xf32>) {
+  // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [%offset], sizes: [1, 1], strides: [8, 1]
+    : memref<4x8xf32> to memref<1x1xf32, strided<[8, 1], offset: ?>>
+
+  // CHECK:      memref.copy %arg1, %reinterpret_cast
+  // CHECK-NOT:  memref.load
+  // CHECK-NOT:  memref.store
+  memref.copy %src, %reinterpret_cast
+    : memref<1x1xf32>
+      to memref<1x1xf32, strided<[8, 1], offset: ?>>
+  return
+}
+
+// CHECK-LABEL: func.func private @negative_concat_2d_dynamic_offset(
+func.func private @negative_concat_2d_dynamic_offset(
+  %offset : index, %src : memref<1x33x4xf32>,
+  %dst : memref<1x33x42xf32>) {
+  // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [%offset], sizes: [1, 33, 4], strides: [1386, 42, 1]
+    : memref<1x33x42xf32>
+      to memref<1x33x4xf32, strided<[1386, 42, 1], offset: ?>>
+
+  // CHECK:      memref.copy %arg1, %reinterpret_cast
+  // CHECK-NOT:  memref.load
+  // CHECK-NOT:  memref.store
+  memref.copy %src, %reinterpret_cast
+    : memref<1x33x4xf32>
+      to memref<1x33x4xf32, strided<[1386, 42, 1], offset: ?>>
+  return
+}
+
+/// Non-unit copied dimension needs stride-based address computation.
+// CHECK-LABEL: func.func private @negative_concat_dynamic_rc_stride(
+func.func private @negative_concat_dynamic_rc_stride(%stride : index,
+  %src : memref<1x33x1xf32>, %dst : memref<1x33x42xf32>) {
+  // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [0], sizes: [1, 33, 1], strides: [1386, %stride, 1]
+    : memref<1x33x42xf32>
+      to memref<1x33x1xf32, strided<[1386, ?, 1]>>
+
+  // CHECK:      memref.copy %arg1, %reinterpret_cast
+  // CHECK-NOT:  memref.load
+  // CHECK-NOT:  memref.store
+  memref.copy %src, %reinterpret_cast
+    : memref<1x33x1xf32>
+      to memref<1x33x1xf32, strided<[1386, ?, 1]>>
   return
 }
 
@@ -222,7 +441,6 @@ func.func private @negative_plain_copy(%src : memref<1x1xf32>,
   return
 }
 
-
 // -----
 
 //===----------------------------------------------------------------------===//

>From d355a9b2dcfedb56f62a12eadf20de1d9c8b79a9 Mon Sep 17 00:00:00 2001
From: Ioana Ghiban <ioana.ghiban at arm.com>
Date: Wed, 17 Jun 2026 17:10:59 +0200
Subject: [PATCH 2/8] Address first round of comments

---
 .../Transforms/ElideReinterpretCast.cpp       | 268 ++++++++++--------
 .../MemRef/elide-reinterpret-cast.mlir        | 264 ++++++++---------
 2 files changed, 264 insertions(+), 268 deletions(-)

diff --git a/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp b/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
index 47aac6b64d092..e510ef9057b3f 100644
--- a/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
+++ b/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
@@ -15,6 +15,7 @@
 #include "mlir/IR/Matchers.h"
 #include "mlir/IR/TypeUtilities.h"
 #include "mlir/Transforms/DialectConversion.h"
+#include <array>
 #include <cassert>
 #include <optional>
 
@@ -29,6 +30,10 @@ using namespace mlir;
 
 namespace {
 
+/// Copy rewrite helpers
+
+/// The copy rewrite stores directly into the reinterpret_cast source, so it
+/// needs concrete base strides instead of layout-map reasoning.
 static std::optional<SmallVector<int64_t>> getIdentityStrides(MemRefType type) {
   if (!type.getLayout().isIdentity() || !type.hasStaticShape())
     return std::nullopt;
@@ -42,19 +47,22 @@ static std::optional<SmallVector<int64_t>> getIdentityStrides(MemRefType type) {
   return strides;
 }
 
+/// Non-unit strided memref dimensions are lowered to loops over base memref
+/// dimensions. Static reinterpret_cast strides connect those dimension spaces
+/// in the currently supported cases.
 static std::optional<unsigned>
-findBaseDimForViewStride(MemRefType baseType, ArrayRef<int64_t> baseStrides,
-                         ArrayRef<bool> usedBaseDims, int64_t viewStride,
-                         int64_t viewSize) {
+findBaseDimForResultStride(MemRefType baseType, ArrayRef<int64_t> baseStrides,
+                           ArrayRef<bool> usedBaseDims, int64_t resultStride,
+                           int64_t resultSize) {
   std::optional<unsigned> fallback;
   for (auto [idx, stride] : llvm::enumerate(baseStrides)) {
-    if (usedBaseDims[idx] || stride != viewStride ||
-        baseType.getDimSize(idx) < viewSize)
+    if (usedBaseDims[idx] || stride != resultStride ||
+        baseType.getDimSize(idx) < resultSize)
       continue;
 
     // Prefer an exact shape match. Otherwise, use the first dimension large
     // enough to contain the copied logical vector.
-    if (baseType.getDimSize(idx) == viewSize)
+    if (baseType.getDimSize(idx) == resultSize)
       return idx;
     if (!fallback)
       fallback = idx;
@@ -62,6 +70,8 @@ findBaseDimForViewStride(MemRefType baseType, ArrayRef<int64_t> baseStrides,
   return fallback;
 }
 
+/// reinterpret_cast offsets are linear element offsets, while `memref.store`
+/// needs one index per base dimension.
 static std::optional<SmallVector<int64_t>>
 delinearizeStaticOffset(int64_t offset, MemRefType baseType,
                         ArrayRef<int64_t> baseStrides) {
@@ -82,6 +92,8 @@ delinearizeStaticOffset(int64_t offset, MemRefType baseType,
   return indices;
 }
 
+/// Dynamic scalar offsets cannot be delinearized statically. They can be used
+/// directly only when the base has a single non-unit dimension to receive them.
 static std::optional<unsigned> getSingleNonUnitDim(MemRefType type) {
   if (!type.hasStaticShape() || type.getRank() == 0)
     return std::nullopt;
@@ -97,56 +109,48 @@ static std::optional<unsigned> getSingleNonUnitDim(MemRefType type) {
   return nonUnitDim;
 }
 
+/// Per-dimension loop nest info.
 struct CopyLoopDimInfo {
-  unsigned viewDim;
-  unsigned dstLoopDim;
-  int64_t loopSize;
+  unsigned copyDim;
+  unsigned baseDim;
+  int64_t size;
 };
 
-struct CopyToLoadStoreInfo {
+/// Rewrite info from reinterpret_cast layout, captured after passing legality
+/// checks.
+struct CopyFromReinterCastInfo {
   SmallVector<CopyLoopDimInfo> loopDims;
-  SmallVector<int64_t> staticOffsetIndices;
+  std::optional<SmallVector<int64_t>> staticOffsetIndices;
   std::optional<unsigned> dynamicOffsetDim;
 };
 
 /// Builds the index mapping needed to replace a copy into a reinterpret_cast
-/// view with scalar stores into the reinterpret_cast base.
-///
-/// Checklist:
-/// - The copy destination must be a `memref.reinterpret_cast`.
-/// - The copy source, reinterpret_cast source, and reinterpret_cast result must
-///   be ranked memrefs with static shapes.
-/// - The reinterpret_cast source/result ranks must match.
-/// - The reinterpret_cast source must have static identity layout.
-/// - Each non-unit copied view dimension must have a static stride that maps to
-///   an identity-layout base dimension.
-/// - Static offsets, dynamic only in scalar or effectively-1D copies
-///   where the offset can be used directly as one base index.
+/// strided memref with scalar stores into the reinterpret_cast base.
 ///
-/// Examples that return true:
+/// Examples that return rewrite info:
 ///
-///   // Scalar-shaped copy. There are no copied non-unit dimensions, so
-///   // dynamic strides in the scalar view do not affect index mapping.
-///   copy memref<1x...x1xf32>
+///   // Scalar-shaped copy. There are no copied non-unit dimensions, so dynamic
+///   // strides in the strided memref do not affect index mapping.
+///   copy memref<1 x ... x 1 x f32>
 ///     to reinterpret_cast memref<base-shape>
-///       to memref<1x...x1xf32, strided<[?, ..., ?], offset: ?>>
+///       to memref<1 x ... x 1 x f32, strided<[?, ..., ?], offset: ?>>
 ///
-///   // Effectively-1D copy. The single non-unit view dimension is mapped to
-///   // an identity-layout base dimension by its static stride.
-///   copy memref<1x...xNx...x1xf32>
+///   // Effectively-1D copy. The single non-unit strided memref dimension is
+///   // mapped to an identity-layout base dimension by its static stride.
+///   copy memref<1 x ... x N x ... x 1 x f32>
 ///     to reinterpret_cast memref<base-shape>
-///       to memref<1x...xNx...x1xf32, strided<[..., S, ...]>>
+///       to memref<1 x ... x N x ... x 1 x f32, strided<[..., S, ...]>>
 ///
-///   // Multidimensional copy with static offset. Each non-unit view dimension
-///   // is mapped independently by its static stride.
-///   copy memref<1x...xNx...xKx...x1xf32>
+///   // Multidimensional copy with static offset. Each non-unit strided memref
+///   // dimension is mapped independently by its static stride.
+///   copy memref<1 x ... x N_0 x ... x N_K x ... x 1 x f32>
 ///     to reinterpret_cast memref<base-shape>
-///       to memref<1x...xNx...xKx...x1xf32,
-///                 strided<[..., S0, ..., S1, ...], offset: O>>
+///       to memref<1 x ... x N_0 x ... x N_K x ... x 1 x f32,
+///                 strided<[..., S_0, ..., S_1, ...], offset: O>>
 ///
-/// Examples that return false:
+/// Examples that return no info:
 ///
-///   // Dynamic stride on a copied view dimension.
+///   // Dynamic stride on a copied strided memref dimension.
 ///   copy memref<1xNxf32>
 ///     to reinterpret_cast memref<1xNxMxf32>
 ///       to memref<1xNxf32, strided<[?, ?]>>
@@ -155,32 +159,35 @@ struct CopyToLoadStoreInfo {
 ///   copy memref<1xNxKxf32>
 ///     to reinterpret_cast memref<1xNxMxf32>
 ///       to memref<1xNxKxf32, strided<[N*M, M, 1], offset: ?>>
-static std::optional<CopyToLoadStoreInfo>
-getCopyToLoadStoreInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
+static std::optional<CopyFromReinterCastInfo>
+getCopyFromReinterCastInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
   MemRefType srcType = dyn_cast<MemRefType>(op.getSource().getType());
   MemRefType baseType = dyn_cast<MemRefType>(rc.getSource().getType());
-  MemRefType viewType = dyn_cast<MemRefType>(rc.getType());
-  // TODO: Support unranked copy sources or reinterpret_cast sources.
-  if (!srcType || !baseType || !viewType)
+  MemRefType resultType = dyn_cast<MemRefType>(rc.getType());
+
+  // Ranked memref types are required to statically build load/store index
+  // lists.
+  if (!srcType || !baseType || !resultType)
+    return std::nullopt;
+
+  if (srcType.getShape() != resultType.getShape())
     return std::nullopt;
 
   // TODO: Support rank-changing reinterpret_casts by converting the
-  // destination view indices to base indices. For example, a copy to a
-  // memref<2x3xf32> view of memref<6xf32> needs to linearize the view indices
-  // as `i * 3 + j`, then combine that with the reinterpret_cast offset before
-  // indexing the rank-1 base memref.
-  if (baseType.getRank() != viewType.getRank())
+  // strided memref indices to base indices. For example, a copy to
+  // a strided memref<2x3xf32> of base memref<6xf32> needs to linearize the
+  // strided memref indices as `i * 3 + j`, then combine that with the
+  // reinterpret_cast offset before indexing the rank-1 base memref.
+  if (baseType.getRank() != resultType.getRank())
     return std::nullopt;
 
   // TODO: Support dynamic shapes with mixed size operands as loop bounds.
   if (!(srcType.hasStaticShape() && baseType.hasStaticShape() &&
-        viewType.hasStaticShape()))
+        resultType.hasStaticShape()))
     return std::nullopt;
 
-  assert(srcType.getShape() == viewType.getShape() &&
-         "copy source and destination are expected to have the same shape");
-
-  // Store indices are formed in the reinterpret_cast source layout.
+  // Map reinterpret_cast strided memref dimensions to source dimensions by
+  // stride.
   std::optional<SmallVector<int64_t>> baseStrides =
       getIdentityStrides(baseType);
   // TODO: Support non-identity reinterpret_cast source layouts by using the
@@ -188,60 +195,68 @@ getCopyToLoadStoreInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
   if (!baseStrides)
     return std::nullopt;
 
-  CopyToLoadStoreInfo info;
+  CopyFromReinterCastInfo info;
   SmallVector<bool> usedBaseDims(baseType.getRank(), false);
 
-  // Non-unit view dimensions become loop dimensions in the scalar rewrite.
-  for (auto [viewDim, viewSize] : llvm::enumerate(viewType.getShape())) {
-    if (viewSize == 1)
+  for (auto [resultDim, resultSize] : llvm::enumerate(resultType.getShape())) {
+    if (resultSize == 1)
       continue;
 
-    // TODO: Support dynamic strides on copied view dimensions.
-    if (ShapedType::isDynamic(rc.getStaticStrides()[viewDim]))
+    // TODO: Support dynamic strides on copied dimensions.
+    if (ShapedType::isDynamic(rc.getStaticStrides()[resultDim]))
       return std::nullopt;
 
-    std::optional<unsigned> dstLoopDim =
-        findBaseDimForViewStride(baseType, *baseStrides, usedBaseDims,
-                                 rc.getStaticStrides()[viewDim], viewSize);
-    assert(dstLoopDim &&
+    // Non-unit strided memref dimensions become loop dimensions in the scalar
+    // rewrite.
+    std::optional<unsigned> baseDim = findBaseDimForResultStride(
+        baseType, *baseStrides, usedBaseDims, rc.getStaticStrides()[resultDim],
+        resultSize);
+    assert(baseDim &&
            "static reinterpret_cast stride must map to an identity base "
            "dimension");
 
-    usedBaseDims[*dstLoopDim] = true;
-    info.loopDims.push_back(
-        CopyLoopDimInfo{static_cast<unsigned>(viewDim), *dstLoopDim, viewSize});
+    usedBaseDims[*baseDim] = true;
+    info.loopDims.push_back(CopyLoopDimInfo{static_cast<unsigned>(resultDim),
+                                            *baseDim, resultSize});
   }
 
-  ArrayRef<int64_t> staticOffsets = rc.getStaticOffsets();
-  assert(staticOffsets.size() == 1 && "Expecting single offset");
-  if (!ShapedType::isDynamic(staticOffsets[0])) {
+  ArrayRef<int64_t> offsets = rc.getStaticOffsets();
+  // FIXME: Despite what `getStaticOffsets` implies, `reinterpret_cast` takes
+  // only a single offset. That should be fixed at the op definition level.
+  assert(offsets.size() == 1 && "Expecting single offset");
+  if (!ShapedType::isDynamic(offsets[0])) {
     // Static offsets are converted to base indices.
     std::optional<SmallVector<int64_t>> offsetIndices =
-        delinearizeStaticOffset(staticOffsets[0], baseType, *baseStrides);
+        delinearizeStaticOffset(offsets[0], baseType, *baseStrides);
     assert(offsetIndices &&
            "static reinterpret_cast offset must delinearize to in-bounds base "
            "indices");
 
     for (const CopyLoopDimInfo &loopDim : info.loopDims) {
-      assert((*offsetIndices)[loopDim.dstLoopDim] + loopDim.loopSize <=
-                 baseType.getDimSize(loopDim.dstLoopDim) &&
+      assert((*offsetIndices)[loopDim.baseDim] + loopDim.size <=
+                 baseType.getDimSize(loopDim.baseDim) &&
              "reinterpret_cast metadata describes an invalid accessible "
              "region");
     }
-    info.staticOffsetIndices = std::move(*offsetIndices);
+    info.staticOffsetIndices = std::move(offsetIndices);
     return info;
   }
 
   // Dynamic offsets are kept only when they can be used as a single base index.
-  // TODO: Support multidimensional dynamic offsets with div/mod
-  // delinearization.
+  // TODO: Support dynamic offsets for copies with multiple loop dimensions by
+  // delinearizing the offset into base start indices at runtime before adding
+  // loop IVs.
   if (info.loopDims.size() > 1)
     return std::nullopt;
 
   if (info.loopDims.empty()) {
-    // TODO: Support scalar dynamic offsets into bases with multiple non-unit
-    // dimensions, and all-unit bases with a provably zero offset.
+    // Scalar-shaped strided memrefs copy one element, so a dynamic linear
+    // offset can be used directly only when the base has exactly one non-unit
+    // dimension.
     std::optional<unsigned> nonUnitDim = getSingleNonUnitDim(baseType);
+    // TODO: Support scalar dynamic offsets into bases with multiple non-unit
+    // dimensions by delinearizing the single accessed element offset at
+    // runtime.
     if (!nonUnitDim)
       return std::nullopt;
 
@@ -249,9 +264,9 @@ getCopyToLoadStoreInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
     return info;
   }
 
-  unsigned dstLoopDim = info.loopDims.front().dstLoopDim;
+  unsigned baseDim = info.loopDims.front().baseDim;
   info.dynamicOffsetDim =
-      (*baseStrides)[dstLoopDim] == 1 ? dstLoopDim : baseStrides->size() - 1;
+      (*baseStrides)[baseDim] == 1 ? baseDim : baseStrides->size() - 1;
   return info;
 }
 
@@ -259,18 +274,18 @@ getCopyToLoadStoreInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
 /// scalar load/store operations.
 ///
 ///   // BEFORE (scalar copy)
-///   %view = memref.reinterpret_cast %dst
+///   %strided = memref.reinterpret_cast %dst
 ///     to offset: [O], sizes: [1, ..., 1], strides: [...]
-///   memref.copy %src, %view
+///   memref.copy %src, %strided
 ///
 ///   // AFTER
 ///   %v = memref.load %src[0, ..., 0]
 ///   memref.store %v, %dst[delinearized(O)]
 ///
 ///   // BEFORE (effectively-1D copy)
-///   %view = memref.reinterpret_cast %dst
+///   %strided = memref.reinterpret_cast %dst
 ///     to offset: [O], sizes: [1, N, 1], strides: [...]
-///   memref.copy %src, %view
+///   memref.copy %src, %strided
 ///
 ///   // AFTER
 ///   scf.for %i = 0 to N step 1 {
@@ -279,9 +294,9 @@ getCopyToLoadStoreInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
 ///   }
 ///
 ///   // BEFORE (multidimensional copy with static offset)
-///   %view = memref.reinterpret_cast %dst
+///   %strided = memref.reinterpret_cast %dst
 ///     to offset: [O], sizes: [1, N, K], strides: [...]
-///   memref.copy %src, %view
+///   memref.copy %src, %strided
 ///
 ///   // AFTER
 ///   scf.for %i = 0 to N step 1 {
@@ -302,8 +317,8 @@ struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
       return rewriter.notifyMatchFailure(
           op, "target is not a memref.reinterpret_cast");
 
-    std::optional<CopyToLoadStoreInfo> copyInfo =
-        getCopyToLoadStoreInfo(op, rc);
+    std::optional<CopyFromReinterCastInfo> copyInfo =
+        getCopyFromReinterCastInfo(op, rc);
     if (!copyInfo)
       return rewriter.notifyMatchFailure(
           op, "reinterpret_cast does not match scalar or loop copy region");
@@ -315,43 +330,51 @@ struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
     MemRefType srcType = cast<MemRefType>(src.getType());
     MemRefType dstType = cast<MemRefType>(dst.getType());
 
-    Value zero = arith::ConstantIndexOp::create(rewriter, loc, 0);
-    Value one;
-    // Reuse common index constants across bounds, steps, and static offsets.
-    // Keep `%c1` lazy so scalar copies without loops do not create an unused
-    // loop-step constant.
+    // Reuse common index constants across bounds, steps, and static offsets,
+    // but avoid creating them for rank-0 copies.
+    std::array<Value, 2> cachedIndexConstants;
     auto getOrCreateIndexConstant = [&](int64_t value) -> Value {
-      if (value == 0)
-        return zero;
-      if (value == 1) {
-        if (!one)
-          one = arith::ConstantIndexOp::create(rewriter, loc, 1);
-        return one;
+      if (value == 0 || value == 1) {
+        Value &cached = cachedIndexConstants[value];
+        if (!cached)
+          cached = arith::ConstantIndexOp::create(rewriter, loc, value);
+        return cached;
       }
       return arith::ConstantIndexOp::create(rewriter, loc, value);
     };
+    auto getZeroIndices = [&](int64_t rank) {
+      SmallVector<Value> indices;
+      indices.reserve(rank);
+      if (rank != 0)
+        indices.append(rank, getOrCreateIndexConstant(0));
+      return indices;
+    };
 
-    // Materialize all loop bounds before building the loop nest. Otherwise an
-    // inner-loop bound may be created inside an outer loop body.
+    // Create all loop bounds before building the loop nest. Otherwise an
+    // inner-loop bound can be inserted inside an outer loop body.
     SmallVector<Value> upperBounds;
     upperBounds.reserve(copyInfo->loopDims.size());
     for (const CopyLoopDimInfo &loopDim : copyInfo->loopDims)
-      upperBounds.push_back(getOrCreateIndexConstant(loopDim.loopSize));
+      upperBounds.push_back(getOrCreateIndexConstant(loopDim.size));
 
-    SmallVector<Value> baseStoreIndices(dstType.getRank(), zero);
-    // Static offsets were already delinearized into base indices. Materialize
-    // the non-zero starting indices before creating loop bodies.
-    if (!copyInfo->staticOffsetIndices.empty()) {
+    SmallVector<Value> baseStoreIndices = getZeroIndices(dstType.getRank());
+    // Static offsets were already delinearized into base indices. Fill the
+    // non-zero starting indices before creating loop bodies.
+    if (copyInfo->staticOffsetIndices) {
       for (auto [idx, offset] :
-           llvm::enumerate(copyInfo->staticOffsetIndices)) {
+           llvm::enumerate(*copyInfo->staticOffsetIndices)) {
         if (offset == 0)
           continue;
         baseStoreIndices[idx] = getOrCreateIndexConstant(offset);
       }
-    } else if (copyInfo->dynamicOffsetDim) {
+    } else {
       // Supported dynamic offsets are used directly in exactly one base
-      // dimension selected by getCopyToLoadStoreInfo.
+      // dimension selected by getCopyFromReinterCastInfo.
+      assert(copyInfo->dynamicOffsetDim &&
+             "expected dynamic offset dimension for dynamic offset");
       SmallVector<OpFoldResult> offsets = rc.getMixedOffsets();
+      // FIXME: Despite what `getMixedOffsets` implies, `reinterpret_cast` takes
+      // only a single offset. That should be fixed at the op definition level.
       assert(offsets.size() == 1 && "Expecting single offset");
       baseStoreIndices[*copyInfo->dynamicOffsetDim] =
           getValueOrCreateConstantIndexOp(rewriter, loc, offsets[0]);
@@ -360,27 +383,30 @@ struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
     // Scope for OpBuilder::InsertionGuard.
     {
       OpBuilder::InsertionGuard guard(rewriter);
+      Value lowerBound;
       Value step;
-      if (!upperBounds.empty())
+      if (!upperBounds.empty()) {
+        lowerBound = getOrCreateIndexConstant(0);
         step = getOrCreateIndexConstant(1);
+      }
 
       SmallVector<Value> loopIvs;
       loopIvs.reserve(copyInfo->loopDims.size());
 
-      // Build one nested loop per non-unit copied view dimension.
+      // Build one nested loop per non-unit copied strided memref dimension.
       for (Value upperBound : upperBounds) {
         scf::ForOp loop =
-            scf::ForOp::create(rewriter, loc, zero, upperBound, step);
+            scf::ForOp::create(rewriter, loc, lowerBound, upperBound, step);
         loopIvs.push_back(loop.getInductionVar());
         rewriter.setInsertionPointToStart(loop.getBody());
       }
 
-      // Load indices are zero except for copied view dimensions, which use the
-      // corresponding loop induction variables.
-      SmallVector<Value> loadIndices(srcType.getRank(), zero);
+      // Load indices are zero except for copied strided memref dimensions,
+      // which use the corresponding loop induction variables.
+      SmallVector<Value> loadIndices = getZeroIndices(srcType.getRank());
       unsigned loopIndex = 0;
       for (const CopyLoopDimInfo &loopDim : copyInfo->loopDims)
-        loadIndices[loopDim.viewDim] = loopIvs[loopIndex++];
+        loadIndices[loopDim.copyDim] = loopIvs[loopIndex++];
 
       // Store indices start from the offset-derived base indices. Add each loop
       // IV to the mapped base dimension.
@@ -388,11 +414,11 @@ struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
       loopIndex = 0;
       for (const CopyLoopDimInfo &loopDim : copyInfo->loopDims) {
         Value iv = loopIvs[loopIndex++];
-        if (storeIndices[loopDim.dstLoopDim] == zero) {
-          storeIndices[loopDim.dstLoopDim] = iv;
+        if (storeIndices[loopDim.baseDim] == getOrCreateIndexConstant(0)) {
+          storeIndices[loopDim.baseDim] = iv;
         } else {
-          storeIndices[loopDim.dstLoopDim] = arith::AddIOp::create(
-              rewriter, loc, storeIndices[loopDim.dstLoopDim], iv);
+          storeIndices[loopDim.baseDim] = arith::AddIOp::create(
+              rewriter, loc, storeIndices[loopDim.baseDim], iv);
         }
       }
 
@@ -680,7 +706,7 @@ struct ElideReinterpretCastPass
       auto rc = op.getTarget().getDefiningOp<memref::ReinterpretCastOp>();
       if (!rc)
         return true;
-      return !getCopyToLoadStoreInfo(op, rc);
+      return !getCopyFromReinterCastInfo(op, rc);
     });
     target.addDynamicallyLegalOp<memref::LoadOp>([](memref::LoadOp op) {
       auto rc = op.getMemRef().getDefiningOp<memref::ReinterpretCastOp>();
diff --git a/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir b/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
index 90431fb507c1e..044e12cec42af 100644
--- a/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
+++ b/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
@@ -5,10 +5,10 @@
 // Positive tests
 //===----------------------------------------------------------------------===//
 
-// CHECK-LABEL: func.func private @concat_zero_offset(
+// CHECK-LABEL: func.func private @copy_to_strided_zero_offset(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x108xf32>
-func.func private @concat_zero_offset(%src : memref<1x1xf32>,
+func.func private @copy_to_strided_zero_offset(%src : memref<1x1xf32>,
   %dst : memref<1x108xf32>) {
   /// reinterpret_cast removed
   // CHECK-NOT:  memref.reinterpret_cast
@@ -23,13 +23,14 @@ func.func private @concat_zero_offset(%src : memref<1x1xf32>,
   // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]]] : memref<1x108xf32>
   memref.copy %src, %reinterpret_cast
     : memref<1x1xf32> to memref<1x1xf32>
+  // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @concat_nonzero_offset(
+// CHECK-LABEL: func.func private @copy_to_strided_nonzero_offset(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x108xf32>
-func.func private @concat_nonzero_offset(%src : memref<1x1xf32>,
+func.func private @copy_to_strided_nonzero_offset(%src : memref<1x1xf32>,
   %dst : memref<1x108xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -45,14 +46,15 @@ func.func private @concat_nonzero_offset(%src : memref<1x1xf32>,
   memref.copy %src, %reinterpret_cast
     : memref<1x1xf32>
       to memref<1x1xf32, strided<[1, 1], offset: 1>>
+  // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @concat_dynamic_offset(
+// CHECK-LABEL: func.func private @copy_to_strided_dynamic_offset(
 // CHECK-SAME:   %[[OFF:.*]]: index
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x108xf32>
-func.func private @concat_dynamic_offset(%offset: index, %src : memref<1x1xf32>,
+func.func private @copy_to_strided_dynamic_offset(%offset: index, %src : memref<1x1xf32>,
   %dst : memref<1x108xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -69,35 +71,17 @@ func.func private @concat_dynamic_offset(%offset: index, %src : memref<1x1xf32>,
   memref.copy %src, %reinterpret_cast
     : memref<1x1xf32>
       to memref<1x1xf32, strided<[1, 1], offset: ?>>
-  return
-}
-
-// CHECK-LABEL: func.func private @concat_strided(
-// CHECK-SAME:   %[[SRC:.*]]: memref<1x1xf32>
-// CHECK-SAME:   %[[DST:.*]]: memref<1x108xf32>
-func.func private @concat_strided(%src : memref<1x1xf32>,
-  %dst : memref<1x108xf32>) {
-  // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [0], sizes: [1, 1], strides: [107, 2]
-    : memref<1x108xf32> to memref<1x1xf32, strided<[107, 2]>>
-
   // CHECK-NOT:  memref.copy
-  // CHECK:      %[[C0:.*]] = arith.constant 0 : index
-  // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]]] : memref<1x1xf32>
-  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]]] : memref<1x108xf32>
-  memref.copy %src, %reinterpret_cast
-    : memref<1x1xf32> to memref<1x1xf32, strided<[107, 2]>>
   return
 }
 
-// Dynamic strides are irrelevant because all view indices are zero.
-// CHECK-LABEL: func.func private @concat_dynamic_stride(
+// Dynamic strides are irrelevant because all strided memref indices are zero.
+// CHECK-LABEL: func.func private @copy_to_strided_dynamic_stride(
 // CHECK-SAME:   %[[STR0:[A-Za-z][A-Za-z0-9-]*]]: index
 // CHECK-SAME:   %[[STR1:[A-Za-z][A-Za-z0-9-]*]]: index
 // CHECK-SAME:   %[[SRC:[A-Za-z][A-Za-z0-9-]*]]: memref<1x1xf32>
 // CHECK-SAME:   %[[DST:[A-Za-z][A-Za-z0-9-]*]]: memref<1x108xf32>
-func.func private @concat_dynamic_stride(%stride0: index,
+func.func private @copy_to_strided_dynamic_stride(%stride0: index,
   %stride1: index, %src : memref<1x1xf32>, %dst : memref<1x108xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -113,50 +97,30 @@ func.func private @concat_dynamic_stride(%stride0: index,
   memref.copy %src, %reinterpret_cast
     : memref<1x1xf32>
       to memref<1x1xf32, strided<[?, ?]>>
-  return
-}
-
-// CHECK-LABEL: func.func private @concat_rank1(
-// CHECK-SAME:   %[[SRC:.*]]: memref<1xf32>
-// CHECK-SAME:   %[[DST:.*]]: memref<108xf32>
-func.func private @concat_rank1(%src : memref<1xf32>, %dst : memref<108xf32>) {
-  // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [0], sizes: [1], strides: [1]
-    : memref<108xf32> to memref<1xf32>
-
   // CHECK-NOT:  memref.copy
-  // CHECK:      %[[C0:.*]] = arith.constant 0 : index
-  // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]]] : memref<1xf32>
-  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]]] : memref<108xf32>
-  memref.copy %src, %reinterpret_cast
-    : memref<1xf32> to memref<1xf32>
   return
 }
 
-// CHECK-LABEL: func.func private @concat_rank3(
-// CHECK-SAME:   %[[SRC:.*]]: memref<1x1x1xf32>
-// CHECK-SAME:   %[[DST:.*]]: memref<1x1x108xf32>
-func.func private @concat_rank3(%src : memref<1x1x1xf32>,
-  %dst : memref<1x1x108xf32>) {
+// CHECK-LABEL: func.func private @copy_to_strided_rank0(
+// CHECK-SAME:   %[[SRC:.*]]: memref<f32>, %[[DST:.*]]: memref<f32>
+func.func private @copy_to_strided_rank0(%src : memref<f32>, %dst : memref<f32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [0], sizes: [1, 1, 1], strides: [1, 1, 1]
-    : memref<1x1x108xf32> to memref<1x1x1xf32>
+    to offset: [0], sizes: [], strides: []
+    : memref<f32> to memref<f32>
 
   // CHECK-NOT:  memref.copy
-  // CHECK:      %[[C0:.*]] = arith.constant 0 : index
-  // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]], %[[C0]]] : memref<1x1x1xf32>
-  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]], %[[C0]]] : memref<1x1x108xf32>
-  memref.copy %src, %reinterpret_cast
-    : memref<1x1x1xf32> to memref<1x1x1xf32>
+  // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][] : memref<f32>
+  // CHECK:      memref.store %[[VAL]], %[[DST]][] : memref<f32>
+  memref.copy %src, %reinterpret_cast : memref<f32> to memref<f32>
+  // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @concat_0d(
+// CHECK-LABEL: func.func private @copy_to_strided_0d_2d_base(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x1x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
-func.func private @concat_0d(
+func.func private @copy_to_strided_0d_2d_base(
   %src : memref<1x1x1xf32>, %dst : memref<1x33x42xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -169,65 +133,68 @@ func.func private @concat_0d(
   // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]], %[[C0]]] : memref<1x33x42xf32>
   memref.copy %src, %reinterpret_cast
     : memref<1x1x1xf32> to memref<1x1x1xf32>
+  // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @concat_1d_vector_zero_offset(
-// CHECK-SAME:   %[[SRC:.*]]: memref<1x33x1xf32>
-// CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
-func.func private @concat_1d_vector_zero_offset(
-  %src : memref<1x33x1xf32>, %dst : memref<1x33x42xf32>) {
+// CHECK-LABEL: func.func private @copy_to_strided_1d_vector_zero_offset(
+// CHECK-SAME:   %[[SRC:.*]]: memref<1x3x1xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x3x11xf32>
+func.func private @copy_to_strided_1d_vector_zero_offset(
+  %src : memref<1x3x1xf32>, %dst : memref<1x3x11xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [0], sizes: [1, 33, 1], strides: [1386, 42, 1]
-    : memref<1x33x42xf32>
-      to memref<1x33x1xf32, strided<[1386, 42, 1]>>
+    to offset: [0], sizes: [1, 3, 1], strides: [33, 11, 1]
+    : memref<1x3x11xf32>
+      to memref<1x3x1xf32, strided<[33, 11, 1]>>
 
   // CHECK-NOT:  memref.copy
   // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
   // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
-  // CHECK-DAG:  %[[C33:.*]] = arith.constant 33 : index
-  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C33]] step %[[C1]] {
-  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x33x1xf32>
-  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x33x42xf32>
+  // CHECK-DAG:  %[[C3:.*]] = arith.constant 3 : index
+  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C3]] step %[[C1]] {
+  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x3x1xf32>
+  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x3x11xf32>
   // CHECK:      }
   memref.copy %src, %reinterpret_cast
-    : memref<1x33x1xf32>
-      to memref<1x33x1xf32, strided<[1386, 42, 1]>>
+    : memref<1x3x1xf32>
+      to memref<1x3x1xf32, strided<[33, 11, 1]>>
+  // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @concat_1d_vector_nonzero_offset(
-// CHECK-SAME:   %[[SRC:.*]]: memref<1x33x1xf32>
-// CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
-func.func private @concat_1d_vector_nonzero_offset(
-  %src : memref<1x33x1xf32>, %dst : memref<1x33x42xf32>) {
+// CHECK-LABEL: func.func private @copy_to_strided_1d_vector_nonzero_offset(
+// CHECK-SAME:   %[[SRC:.*]]: memref<1x3x1xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x3x11xf32>
+func.func private @copy_to_strided_1d_vector_nonzero_offset(
+  %src : memref<1x3x1xf32>, %dst : memref<1x3x11xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [41], sizes: [1, 33, 1], strides: [1386, 42, 1]
-    : memref<1x33x42xf32>
-      to memref<1x33x1xf32, strided<[1386, 42, 1], offset: 41>>
+    to offset: [10], sizes: [1, 3, 1], strides: [33, 11, 1]
+    : memref<1x3x11xf32>
+      to memref<1x3x1xf32, strided<[33, 11, 1], offset: 10>>
 
   // CHECK-NOT:  memref.copy
   // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
   // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
-  // CHECK-DAG:  %[[C33:.*]] = arith.constant 33 : index
-  // CHECK-DAG:  %[[C41:.*]] = arith.constant 41 : index
-  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C33]] step %[[C1]] {
-  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x33x1xf32>
-  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[C41]]] : memref<1x33x42xf32>
+  // CHECK-DAG:  %[[C3:.*]] = arith.constant 3 : index
+  // CHECK-DAG:  %[[C10:.*]] = arith.constant 10 : index
+  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C3]] step %[[C1]] {
+  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x3x1xf32>
+  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[C10]]] : memref<1x3x11xf32>
   // CHECK:      }
   memref.copy %src, %reinterpret_cast
-    : memref<1x33x1xf32>
-      to memref<1x33x1xf32, strided<[1386, 42, 1], offset: 41>>
+    : memref<1x3x1xf32>
+      to memref<1x3x1xf32, strided<[33, 11, 1], offset: 10>>
+  // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @concat_1d_vector_dynamic_offset_same_dim(
+// CHECK-LABEL: func.func private @copy_to_strided_1d_vector_dynamic_offset_in_loop_dim(
 // CHECK-SAME:   %[[OFF:.*]]: index
 // CHECK-SAME:   %[[SRC:.*]]: memref<4xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<42xf32>
-func.func private @concat_1d_vector_dynamic_offset_same_dim(
+func.func private @copy_to_strided_1d_vector_dynamic_offset_in_loop_dim(
   %offset : index, %src : memref<4xf32>, %dst : memref<42xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -245,63 +212,66 @@ func.func private @concat_1d_vector_dynamic_offset_same_dim(
   // CHECK:      }
   memref.copy %src, %reinterpret_cast
     : memref<4xf32> to memref<4xf32, strided<[1], offset: ?>>
+  // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @concat_1d_vector_dynamic_offset_separate_dim(
+// CHECK-LABEL: func.func private @copy_to_strided_1d_vector_dynamic_offset_not_in_loop_dim(
 // CHECK-SAME:   %[[OFF:.*]]: index
-// CHECK-SAME:   %[[SRC:.*]]: memref<1x33x1xf32>
-// CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
-func.func private @concat_1d_vector_dynamic_offset_separate_dim(
-  %offset : index, %src : memref<1x33x1xf32>,
-  %dst : memref<1x33x42xf32>) {
+// CHECK-SAME:   %[[SRC:.*]]: memref<1x3x1xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x3x11xf32>
+func.func private @copy_to_strided_1d_vector_dynamic_offset_not_in_loop_dim(
+  %offset : index, %src : memref<1x3x1xf32>,
+  %dst : memref<1x3x11xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [%offset], sizes: [1, 33, 1], strides: [1386, 42, 1]
-    : memref<1x33x42xf32>
-      to memref<1x33x1xf32, strided<[1386, 42, 1], offset: ?>>
+    to offset: [%offset], sizes: [1, 3, 1], strides: [33, 11, 1]
+    : memref<1x3x11xf32>
+      to memref<1x3x1xf32, strided<[33, 11, 1], offset: ?>>
 
   // CHECK-NOT:  memref.copy
   // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
   // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
-  // CHECK-DAG:  %[[C33:.*]] = arith.constant 33 : index
-  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C33]] step %[[C1]] {
-  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x33x1xf32>
-  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[OFF]]] : memref<1x33x42xf32>
+  // CHECK-DAG:  %[[C3:.*]] = arith.constant 3 : index
+  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C3]] step %[[C1]] {
+  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x3x1xf32>
+  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[OFF]]] : memref<1x3x11xf32>
   // CHECK:      }
   memref.copy %src, %reinterpret_cast
-    : memref<1x33x1xf32>
-      to memref<1x33x1xf32, strided<[1386, 42, 1], offset: ?>>
+    : memref<1x3x1xf32>
+      to memref<1x3x1xf32, strided<[33, 11, 1], offset: ?>>
+  // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @concat_2d_vector_offset(
-// CHECK-SAME:   %[[SRC:.*]]: memref<1x33x4xf32>
-// CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
-func.func private @concat_2d_vector_offset(
-  %src : memref<1x33x4xf32>, %dst : memref<1x33x42xf32>) {
+// CHECK-LABEL: func.func private @copy_to_strided_2d_vector_nonzero_offset(
+// CHECK-SAME:   %[[SRC:.*]]: memref<1x3x4xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x3x11xf32>
+func.func private @copy_to_strided_2d_vector_nonzero_offset(
+  %src : memref<1x3x4xf32>, %dst : memref<1x3x11xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [16], sizes: [1, 33, 4], strides: [1386, 42, 1]
-    : memref<1x33x42xf32>
-      to memref<1x33x4xf32, strided<[1386, 42, 1], offset: 16>>
+    to offset: [7], sizes: [1, 3, 4], strides: [33, 11, 1]
+    : memref<1x3x11xf32>
+      to memref<1x3x4xf32, strided<[33, 11, 1], offset: 7>>
 
   // CHECK-NOT:  memref.copy
   // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
   // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
-  // CHECK-DAG:  %[[C33:.*]] = arith.constant 33 : index
+  // CHECK-DAG:  %[[C3:.*]] = arith.constant 3 : index
   // CHECK-DAG:  %[[C4:.*]] = arith.constant 4 : index
-  // CHECK-DAG:  %[[C16:.*]] = arith.constant 16 : index
-  // CHECK:      scf.for %[[IDX0:.*]] = %[[C0]] to %[[C33]] step %[[C1]] {
+  // CHECK-DAG:  %[[C7:.*]] = arith.constant 7 : index
+  // CHECK:      scf.for %[[IDX0:.*]] = %[[C0]] to %[[C3]] step %[[C1]] {
   // CHECK:        scf.for %[[IDX1:.*]] = %[[C0]] to %[[C4]] step %[[C1]] {
-  // CHECK:          %[[DST_IDX:.*]] = arith.addi %[[C16]], %[[IDX1]] : index
-  // CHECK:          %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX0]], %[[IDX1]]] : memref<1x33x4xf32>
-  // CHECK:          memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX0]], %[[DST_IDX]]] : memref<1x33x42xf32>
+  // CHECK:          %[[DST_IDX:.*]] = arith.addi %[[C7]], %[[IDX1]] : index
+  // CHECK:          %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX0]], %[[IDX1]]] : memref<1x3x4xf32>
+  // CHECK:          memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX0]], %[[DST_IDX]]] : memref<1x3x11xf32>
   // CHECK:        }
   // CHECK:      }
   memref.copy %src, %reinterpret_cast
-    : memref<1x33x4xf32>
-      to memref<1x33x4xf32, strided<[1386, 42, 1], offset: 16>>
+    : memref<1x3x4xf32>
+      to memref<1x3x4xf32, strided<[33, 11, 1], offset: 7>>
+  // CHECK-NOT:  memref.copy
   return
 }
 
@@ -309,8 +279,8 @@ func.func private @concat_2d_vector_offset(
 // Negative tests (must NOT rewrite)
 //===----------------------------------------------------------------------===//
 
-// CHECK-LABEL: func.func private @negative_concat_strided_base(
-func.func private @negative_concat_strided_base(%src: memref<1x1xf32>,
+// CHECK-LABEL: func.func private @negative_copy_to_strided_non_identity_base(
+func.func private @negative_copy_to_strided_non_identity_base(%src: memref<1x1xf32>,
   %dst: memref<8x1xf32, strided<[10, 2]>>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -327,8 +297,8 @@ func.func private @negative_concat_strided_base(%src: memref<1x1xf32>,
   return
 }
 
-// CHECK-LABEL: func.func private @negative_concat_rank_change(
-func.func private @negative_concat_rank_change(%src : memref<2x3xf32>,
+// CHECK-LABEL: func.func private @negative_copy_to_strided_rank_change(
+func.func private @negative_copy_to_strided_rank_change(%src : memref<2x3xf32>,
   %dst : memref<6xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -343,8 +313,8 @@ func.func private @negative_concat_rank_change(%src : memref<2x3xf32>,
   return
 }
 
-// CHECK-LABEL: func.func private @negative_concat_dynamic_copy_source_shape(
-func.func private @negative_concat_dynamic_copy_source_shape(%src : memref<?xf32>,
+// CHECK-LABEL: func.func private @negative_copy_to_strided_dynamic_copy_source_shape(
+func.func private @negative_copy_to_strided_dynamic_copy_source_shape(%src : memref<?xf32>,
   %dst : memref<4xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -359,8 +329,8 @@ func.func private @negative_concat_dynamic_copy_source_shape(%src : memref<?xf32
   return
 }
 
-// CHECK-LABEL: func.func private @negative_concat_dynamic_rc_shapes(
-func.func private @negative_concat_dynamic_rc_shapes(%dim : index,
+// CHECK-LABEL: func.func private @negative_copy_to_strided_dynamic_rc_shapes(
+func.func private @negative_copy_to_strided_dynamic_rc_shapes(%dim : index,
   %src : memref<4xf32>, %dst : memref<?xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -375,8 +345,8 @@ func.func private @negative_concat_dynamic_rc_shapes(%dim : index,
   return
 }
 
-// CHECK-LABEL: func.func private @negative_concat_dynamic_offset_multi_dim_base(
-func.func private @negative_concat_dynamic_offset_multi_dim_base(
+// CHECK-LABEL: func.func private @negative_copy_to_strided_dynamic_offset_multi_dim_base(
+func.func private @negative_copy_to_strided_dynamic_offset_multi_dim_base(
   %offset : index, %src : memref<1x1xf32>, %dst : memref<4x8xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -392,41 +362,41 @@ func.func private @negative_concat_dynamic_offset_multi_dim_base(
   return
 }
 
-// CHECK-LABEL: func.func private @negative_concat_2d_dynamic_offset(
-func.func private @negative_concat_2d_dynamic_offset(
-  %offset : index, %src : memref<1x33x4xf32>,
-  %dst : memref<1x33x42xf32>) {
+// CHECK-LABEL: func.func private @negative_copy_to_strided_2d_dynamic_offset(
+func.func private @negative_copy_to_strided_2d_dynamic_offset(
+  %offset : index, %src : memref<1x3x4xf32>,
+  %dst : memref<1x3x11xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
   %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [%offset], sizes: [1, 33, 4], strides: [1386, 42, 1]
-    : memref<1x33x42xf32>
-      to memref<1x33x4xf32, strided<[1386, 42, 1], offset: ?>>
+    to offset: [%offset], sizes: [1, 3, 4], strides: [33, 11, 1]
+    : memref<1x3x11xf32>
+      to memref<1x3x4xf32, strided<[33, 11, 1], offset: ?>>
 
   // CHECK:      memref.copy %arg1, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
   memref.copy %src, %reinterpret_cast
-    : memref<1x33x4xf32>
-      to memref<1x33x4xf32, strided<[1386, 42, 1], offset: ?>>
+    : memref<1x3x4xf32>
+      to memref<1x3x4xf32, strided<[33, 11, 1], offset: ?>>
   return
 }
 
 /// Non-unit copied dimension needs stride-based address computation.
-// CHECK-LABEL: func.func private @negative_concat_dynamic_rc_stride(
-func.func private @negative_concat_dynamic_rc_stride(%stride : index,
-  %src : memref<1x33x1xf32>, %dst : memref<1x33x42xf32>) {
+// CHECK-LABEL: func.func private @negative_copy_to_strided_dynamic_rc_stride(
+func.func private @negative_copy_to_strided_dynamic_rc_stride(%stride : index,
+  %src : memref<1x3x1xf32>, %dst : memref<1x3x11xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
   %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [0], sizes: [1, 33, 1], strides: [1386, %stride, 1]
-    : memref<1x33x42xf32>
-      to memref<1x33x1xf32, strided<[1386, ?, 1]>>
+    to offset: [0], sizes: [1, 3, 1], strides: [33, %stride, 1]
+    : memref<1x3x11xf32>
+      to memref<1x3x1xf32, strided<[33, ?, 1]>>
 
   // CHECK:      memref.copy %arg1, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
   memref.copy %src, %reinterpret_cast
-    : memref<1x33x1xf32>
-      to memref<1x33x1xf32, strided<[1386, ?, 1]>>
+    : memref<1x3x1xf32>
+      to memref<1x3x1xf32, strided<[33, ?, 1]>>
   return
 }
 

>From 7399855abf4eaf455ae06282947c2345d41d5a41 Mon Sep 17 00:00:00 2001
From: Ioana Ghiban <ioana.ghiban at arm.com>
Date: Fri, 19 Jun 2026 10:45:19 +0200
Subject: [PATCH 3/8] Refine helper function comments

---
 .../Transforms/ElideReinterpretCast.cpp       | 108 ++++++++++--------
 1 file changed, 60 insertions(+), 48 deletions(-)

diff --git a/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp b/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
index e510ef9057b3f..95d7b1f1dc286 100644
--- a/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
+++ b/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
@@ -30,10 +30,11 @@ using namespace mlir;
 
 namespace {
 
-/// Copy rewrite helpers
+//===----------------------------------------------------------------------===//
+// Copy Rewrite Helpers
+//===----------------------------------------------------------------------===//
 
-/// The copy rewrite stores directly into the reinterpret_cast source, so it
-/// needs concrete base strides instead of layout-map reasoning.
+/// Returns row-major strides for static identity-layout memref type.
 static std::optional<SmallVector<int64_t>> getIdentityStrides(MemRefType type) {
   if (!type.getLayout().isIdentity() || !type.hasStaticShape())
     return std::nullopt;
@@ -47,42 +48,54 @@ static std::optional<SmallVector<int64_t>> getIdentityStrides(MemRefType type) {
   return strides;
 }
 
-/// Non-unit strided memref dimensions are lowered to loops over base memref
-/// dimensions. Static reinterpret_cast strides connect those dimension spaces
-/// in the currently supported cases.
-static std::optional<unsigned>
-findBaseDimForResultStride(MemRefType baseType, ArrayRef<int64_t> baseStrides,
-                           ArrayRef<bool> usedBaseDims, int64_t resultStride,
-                           int64_t resultSize) {
-  std::optional<unsigned> fallback;
-  for (auto [idx, stride] : llvm::enumerate(baseStrides)) {
-    if (usedBaseDims[idx] || stride != resultStride ||
-        baseType.getDimSize(idx) < resultSize)
+/// Finds the source dimension for a static reinterpret_cast result dimension.
+/// Dimensions marked in `usedSourceDims` are skipped. Returns the smallest
+/// source dimension whose size is at least the result dimension size, with the
+/// same stride.
+static std::optional<unsigned> findSourceDimForResultDim(
+    memref::ReinterpretCastOp rc, unsigned resultDim, MemRefType sourceType,
+    ArrayRef<int64_t> sourceStrides, ArrayRef<bool> usedSourceDims) {
+  MemRefType resultType = cast<MemRefType>(rc.getType());
+  assert(resultDim < resultType.getRank() && "result dimension out of range");
+  assert(sourceType.getRank() == static_cast<int64_t>(sourceStrides.size()) &&
+         sourceStrides.size() == usedSourceDims.size() &&
+         "expected same-rank source type, strides, and used-dimension mask");
+  assert(!ShapedType::isDynamic(rc.getStaticStrides()[resultDim]) &&
+         "expected static result stride");
+
+  int64_t resultStride = rc.getStaticStrides()[resultDim];
+  int64_t resultSize = resultType.getDimSize(resultDim);
+  std::optional<unsigned> sourceDim;
+  for (auto [idx, stride] : llvm::enumerate(sourceStrides)) {
+    if (usedSourceDims[idx] || stride != resultStride ||
+        sourceType.getDimSize(idx) < resultSize)
       continue;
 
-    // Prefer an exact shape match. Otherwise, use the first dimension large
-    // enough to contain the copied logical vector.
-    if (baseType.getDimSize(idx) == resultSize)
-      return idx;
-    if (!fallback)
-      fallback = idx;
+    if (!sourceDim ||
+        sourceType.getDimSize(idx) < sourceType.getDimSize(*sourceDim))
+      sourceDim = idx;
   }
-  return fallback;
+  return sourceDim;
 }
 
-/// reinterpret_cast offsets are linear element offsets, while `memref.store`
-/// needs one index per base dimension.
+/// Returns source indices for a static reinterpret_cast offset.
 static std::optional<SmallVector<int64_t>>
-delinearizeStaticOffset(int64_t offset, MemRefType baseType,
-                        ArrayRef<int64_t> baseStrides) {
-  if (offset < 0)
+delinearizeStaticOffset(memref::ReinterpretCastOp rc, MemRefType sourceType,
+                        ArrayRef<int64_t> sourceStrides) {
+  ArrayRef<int64_t> offsets = rc.getStaticOffsets();
+  // FIXME: Despite what `getStaticOffsets` implies, `reinterpret_cast` takes
+  // only a single offset. That should be fixed at the op definition level.
+  assert(offsets.size() == 1 && "Expecting single offset");
+  assert(!ShapedType::isDynamic(offsets[0]) && "expected static offset");
+
+  if (offsets[0] < 0)
     return std::nullopt;
 
-  SmallVector<int64_t> indices(baseType.getRank(), 0);
-  int64_t remainder = offset;
-  for (auto [idx, stride] : llvm::enumerate(baseStrides)) {
+  SmallVector<int64_t> indices(sourceType.getRank(), 0);
+  int64_t remainder = offsets[0];
+  for (auto [idx, stride] : llvm::enumerate(sourceStrides)) {
     indices[idx] = remainder / stride;
-    if (indices[idx] >= baseType.getDimSize(idx))
+    if (indices[idx] >= sourceType.getDimSize(idx))
       return std::nullopt;
     remainder %= stride;
   }
@@ -92,14 +105,15 @@ delinearizeStaticOffset(int64_t offset, MemRefType baseType,
   return indices;
 }
 
-/// Dynamic scalar offsets cannot be delinearized statically. They can be used
-/// directly only when the base has a single non-unit dimension to receive them.
+/// Returns the dimension whose static size is not one if it is unique.
 static std::optional<unsigned> getSingleNonUnitDim(MemRefType type) {
-  if (!type.hasStaticShape() || type.getRank() == 0)
+  assert(type.hasStaticShape() && "expected static shape");
+  ArrayRef<int64_t> shape = type.getShape();
+  if (shape.empty())
     return std::nullopt;
 
   std::optional<unsigned> nonUnitDim;
-  for (auto [idx, dim] : llvm::enumerate(type.getShape())) {
+  for (auto [idx, dim] : llvm::enumerate(shape)) {
     if (dim == 1)
       continue;
     if (nonUnitDim)
@@ -186,12 +200,10 @@ getCopyFromReinterCastInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
         resultType.hasStaticShape()))
     return std::nullopt;
 
-  // Map reinterpret_cast strided memref dimensions to source dimensions by
-  // stride.
   std::optional<SmallVector<int64_t>> baseStrides =
       getIdentityStrides(baseType);
-  // TODO: Support non-identity reinterpret_cast source layouts by using the
-  // source layout strides as base strides.
+  // TODO: Support non-identity source layouts by computing source strides from
+  // the layout map.
   if (!baseStrides)
     return std::nullopt;
 
@@ -206,11 +218,11 @@ getCopyFromReinterCastInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
     if (ShapedType::isDynamic(rc.getStaticStrides()[resultDim]))
       return std::nullopt;
 
-    // Non-unit strided memref dimensions become loop dimensions in the scalar
-    // rewrite.
-    std::optional<unsigned> baseDim = findBaseDimForResultStride(
-        baseType, *baseStrides, usedBaseDims, rc.getStaticStrides()[resultDim],
-        resultSize);
+    // Each copied result dimension must map by stride to a source dimension
+    // whose static size >= result dimension size.
+    std::optional<unsigned> baseDim =
+        findSourceDimForResultDim(rc, static_cast<unsigned>(resultDim),
+                                  baseType, *baseStrides, usedBaseDims);
     assert(baseDim &&
            "static reinterpret_cast stride must map to an identity base "
            "dimension");
@@ -225,9 +237,9 @@ getCopyFromReinterCastInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
   // only a single offset. That should be fixed at the op definition level.
   assert(offsets.size() == 1 && "Expecting single offset");
   if (!ShapedType::isDynamic(offsets[0])) {
-    // Static offsets are converted to base indices.
+    // Static offset must delinearize to in-bounds source indices.
     std::optional<SmallVector<int64_t>> offsetIndices =
-        delinearizeStaticOffset(offsets[0], baseType, *baseStrides);
+        delinearizeStaticOffset(rc, baseType, *baseStrides);
     assert(offsetIndices &&
            "static reinterpret_cast offset must delinearize to in-bounds base "
            "indices");
@@ -250,9 +262,9 @@ getCopyFromReinterCastInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
     return std::nullopt;
 
   if (info.loopDims.empty()) {
-    // Scalar-shaped strided memrefs copy one element, so a dynamic linear
-    // offset can be used directly only when the base has exactly one non-unit
-    // dimension.
+    // Dynamic scalar offsets cannot be delinearized statically. They can be
+    // used directly only when the base has a single non-unit dimension to
+    // receive them.
     std::optional<unsigned> nonUnitDim = getSingleNonUnitDim(baseType);
     // TODO: Support scalar dynamic offsets into bases with multiple non-unit
     // dimensions by delinearizing the single accessed element offset at

>From ec9d6848bd0b349da2436011bf7c9c6b1e15478f Mon Sep 17 00:00:00 2001
From: Ioana Ghiban <ioana.ghiban at arm.com>
Date: Fri, 19 Jun 2026 13:05:33 +0200
Subject: [PATCH 4/8] Remove redundant dialect dependency

---
 mlir/include/mlir/Dialect/MemRef/Transforms/Passes.td | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mlir/include/mlir/Dialect/MemRef/Transforms/Passes.td b/mlir/include/mlir/Dialect/MemRef/Transforms/Passes.td
index 7b54be85db340..c6be600247696 100644
--- a/mlir/include/mlir/Dialect/MemRef/Transforms/Passes.td
+++ b/mlir/include/mlir/Dialect/MemRef/Transforms/Passes.td
@@ -20,7 +20,7 @@ def ElideReinterpretCastPass : Pass<"memref-elide-reinterpret-cast"> {
     compatible shapes directly. This simplifies conversion to EmitC.
 }];
   let dependentDialects = [
-      "arith::ArithDialect", "memref::MemRefDialect", "scf::SCFDialect"
+      "arith::ArithDialect", "scf::SCFDialect"
   ];
 }
 

>From bb787ee565ccd81cdd5e29a086e2b26f80665431 Mon Sep 17 00:00:00 2001
From: Ioana Ghiban <ioana.ghiban at arm.com>
Date: Mon, 22 Jun 2026 18:01:38 +0200
Subject: [PATCH 5/8] Address second round of comments

---
 .../Transforms/ElideReinterpretCast.cpp       | 247 +++++++++---------
 .../MemRef/elide-reinterpret-cast.mlir        |  16 ++
 2 files changed, 135 insertions(+), 128 deletions(-)

diff --git a/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp b/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
index 95d7b1f1dc286..6d806b087bdb4 100644
--- a/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
+++ b/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
@@ -12,6 +12,7 @@
 #include "mlir/Dialect/MemRef/IR/MemRef.h"
 #include "mlir/Dialect/MemRef/Transforms/Transforms.h"
 #include "mlir/Dialect/SCF/IR/SCF.h"
+#include "mlir/Dialect/Utils/IndexingUtils.h"
 #include "mlir/IR/Matchers.h"
 #include "mlir/IR/TypeUtilities.h"
 #include "mlir/Transforms/DialectConversion.h"
@@ -34,68 +35,87 @@ namespace {
 // Copy Rewrite Helpers
 //===----------------------------------------------------------------------===//
 
-/// Returns row-major strides for static identity-layout memref type.
-static std::optional<SmallVector<int64_t>> getIdentityStrides(MemRefType type) {
-  if (!type.getLayout().isIdentity() || !type.hasStaticShape())
-    return std::nullopt;
+/// Per-dimension loop nest info.
+struct CopyLoopDimInfo {
+  unsigned copyDim;
+  unsigned baseDim;
+  int64_t size;
+};
 
-  SmallVector<int64_t> strides(type.getRank(), 1);
-  int64_t stride = 1;
-  for (int64_t dim = type.getRank() - 1; dim >= 0; --dim) {
-    strides[dim] = stride;
-    stride *= type.getDimSize(dim);
-  }
-  return strides;
-}
+/// Rewrite info from reinterpret_cast layout, captured after passing legality
+/// checks.
+struct CopyFromReinterCastInfo {
+  // Loop bounds that non-scalar loads "lower" to
+  SmallVector<CopyLoopDimInfo> loopDims;
+  // Deinearized offsets to in-bounds base indices.
+  std::optional<SmallVector<int64_t>> staticOffsetIdxs;
+  // reinterpret_cast dynamic offsets only supported for single non-unit
+  // dimension base, stored here to receive them.
+  std::optional<unsigned> dynamicOffsetDim;
+};
+
+/// Maps non-unit reinterpret_cast result dimensions to distinct base
+/// dimensions.
+static bool findBaseDimForResultDim(memref::ReinterpretCastOp rc,
+                                    CopyFromReinterCastInfo &info) {
+  MemRefType resType = dyn_cast<MemRefType>(rc.getType());
+  MemRefType baseType = dyn_cast<MemRefType>(rc.getSource().getType());
+  SmallVector<int64_t> baseIdentityStrides =
+      computeStrides(baseType.getShape());
 
-/// Finds the source dimension for a static reinterpret_cast result dimension.
-/// Dimensions marked in `usedSourceDims` are skipped. Returns the smallest
-/// source dimension whose size is at least the result dimension size, with the
-/// same stride.
-static std::optional<unsigned> findSourceDimForResultDim(
-    memref::ReinterpretCastOp rc, unsigned resultDim, MemRefType sourceType,
-    ArrayRef<int64_t> sourceStrides, ArrayRef<bool> usedSourceDims) {
-  MemRefType resultType = cast<MemRefType>(rc.getType());
-  assert(resultDim < resultType.getRank() && "result dimension out of range");
-  assert(sourceType.getRank() == static_cast<int64_t>(sourceStrides.size()) &&
-         sourceStrides.size() == usedSourceDims.size() &&
-         "expected same-rank source type, strides, and used-dimension mask");
-  assert(!ShapedType::isDynamic(rc.getStaticStrides()[resultDim]) &&
-         "expected static result stride");
-
-  int64_t resultStride = rc.getStaticStrides()[resultDim];
-  int64_t resultSize = resultType.getDimSize(resultDim);
-  std::optional<unsigned> sourceDim;
-  for (auto [idx, stride] : llvm::enumerate(sourceStrides)) {
-    if (usedSourceDims[idx] || stride != resultStride ||
-        sourceType.getDimSize(idx) < resultSize)
+  // Each result loop IV is added directly to one base index. Reusing a base
+  // dimension would require delinearizing the combined linear offset.
+  SmallVector<bool> usedBaseDims(baseType.getRank(), false);
+
+  // Populate one loop-dimension entry for each non-unit result dimension.
+  for (auto [resultDim, resultSize] : llvm::enumerate(resType.getShape())) {
+    if (resultSize == 1)
       continue;
 
-    if (!sourceDim ||
-        sourceType.getDimSize(idx) < sourceType.getDimSize(*sourceDim))
-      sourceDim = idx;
+    // TODO: Support dynamic strides on copied dimensions.
+    if (ShapedType::isDynamic(rc.getStaticStrides()[resultDim]))
+      return false;
+
+    int64_t resultStride = rc.getStaticStrides()[resultDim];
+    std::optional<unsigned> baseDim;
+    // Find an unused base dimension with matching stride and enough elements.
+    for (auto [idx, stride] : llvm::enumerate(baseIdentityStrides)) {
+      if (usedBaseDims[idx] || stride != resultStride ||
+          baseType.getDimSize(idx) < resultSize)
+        continue;
+
+      if (!baseDim || baseType.getDimSize(idx) < baseType.getDimSize(*baseDim))
+        baseDim = idx;
+    }
+    if (!baseDim)
+      return false;
+
+    usedBaseDims[*baseDim] = true;
+    info.loopDims.push_back(CopyLoopDimInfo{static_cast<unsigned>(resultDim),
+                                            *baseDim, resultSize});
   }
-  return sourceDim;
+  return true;
 }
 
-/// Returns source indices for a static reinterpret_cast offset.
+/// Returns base indices for a static reinterpret_cast offset.
 static std::optional<SmallVector<int64_t>>
-delinearizeStaticOffset(memref::ReinterpretCastOp rc, MemRefType sourceType,
-                        ArrayRef<int64_t> sourceStrides) {
-  ArrayRef<int64_t> offsets = rc.getStaticOffsets();
+delinearizeStaticRCOffset(memref::ReinterpretCastOp rc) {
+  ArrayRef<int64_t> rcOffsets = rc.getStaticOffsets();
   // FIXME: Despite what `getStaticOffsets` implies, `reinterpret_cast` takes
   // only a single offset. That should be fixed at the op definition level.
-  assert(offsets.size() == 1 && "Expecting single offset");
-  assert(!ShapedType::isDynamic(offsets[0]) && "expected static offset");
+  assert(rcOffsets.size() == 1 && "Expecting single offset");
+  assert(!ShapedType::isDynamic(rcOffsets[0]) && "expected static offset");
 
-  if (offsets[0] < 0)
+  if (rcOffsets[0] < 0)
     return std::nullopt;
 
-  SmallVector<int64_t> indices(sourceType.getRank(), 0);
-  int64_t remainder = offsets[0];
-  for (auto [idx, stride] : llvm::enumerate(sourceStrides)) {
+  MemRefType baseType = dyn_cast<MemRefType>(rc.getSource().getType());
+  SmallVector<int64_t> indices(baseType.getRank(), 0);
+  int64_t remainder = rcOffsets[0];
+  SmallVector<int64_t> baseStrides = computeStrides(baseType.getShape());
+  for (auto [idx, stride] : llvm::enumerate(baseStrides)) {
     indices[idx] = remainder / stride;
-    if (indices[idx] >= sourceType.getDimSize(idx))
+    if (indices[idx] >= baseType.getDimSize(idx))
       return std::nullopt;
     remainder %= stride;
   }
@@ -123,21 +143,6 @@ static std::optional<unsigned> getSingleNonUnitDim(MemRefType type) {
   return nonUnitDim;
 }
 
-/// Per-dimension loop nest info.
-struct CopyLoopDimInfo {
-  unsigned copyDim;
-  unsigned baseDim;
-  int64_t size;
-};
-
-/// Rewrite info from reinterpret_cast layout, captured after passing legality
-/// checks.
-struct CopyFromReinterCastInfo {
-  SmallVector<CopyLoopDimInfo> loopDims;
-  std::optional<SmallVector<int64_t>> staticOffsetIndices;
-  std::optional<unsigned> dynamicOffsetDim;
-};
-
 /// Builds the index mapping needed to replace a copy into a reinterpret_cast
 /// strided memref with scalar stores into the reinterpret_cast base.
 ///
@@ -174,86 +179,70 @@ struct CopyFromReinterCastInfo {
 ///     to reinterpret_cast memref<1xNxMxf32>
 ///       to memref<1xNxKxf32, strided<[N*M, M, 1], offset: ?>>
 static std::optional<CopyFromReinterCastInfo>
-getCopyFromReinterCastInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
-  MemRefType srcType = dyn_cast<MemRefType>(op.getSource().getType());
-  MemRefType baseType = dyn_cast<MemRefType>(rc.getSource().getType());
-  MemRefType resultType = dyn_cast<MemRefType>(rc.getType());
+getCopyFromReinterCastInfo(memref::CopyOp copy, memref::ReinterpretCastOp rc) {
+  MemRefType cpSrcType = dyn_cast<MemRefType>(copy.getSource().getType());
+  MemRefType rcBaseType = dyn_cast<MemRefType>(rc.getSource().getType());
+  MemRefType rcResType = dyn_cast<MemRefType>(rc.getType());
 
   // Ranked memref types are required to statically build load/store index
   // lists.
-  if (!srcType || !baseType || !resultType)
+  if (!cpSrcType || !rcBaseType || !rcResType)
     return std::nullopt;
 
-  if (srcType.getShape() != resultType.getShape())
+  if (cpSrcType.getShape() != rcResType.getShape())
     return std::nullopt;
 
-  // TODO: Support rank-changing reinterpret_casts by converting the
+  // TODO: Support rank-modifying reinterpret_casts by converting the
   // strided memref indices to base indices. For example, a copy to
   // a strided memref<2x3xf32> of base memref<6xf32> needs to linearize the
   // strided memref indices as `i * 3 + j`, then combine that with the
   // reinterpret_cast offset before indexing the rank-1 base memref.
-  if (baseType.getRank() != resultType.getRank())
+  if (rcBaseType.getRank() != rcResType.getRank())
     return std::nullopt;
 
   // TODO: Support dynamic shapes with mixed size operands as loop bounds.
-  if (!(srcType.hasStaticShape() && baseType.hasStaticShape() &&
-        resultType.hasStaticShape()))
+  if (!(cpSrcType.hasStaticShape() && rcBaseType.hasStaticShape() &&
+        rcResType.hasStaticShape()))
     return std::nullopt;
 
-  std::optional<SmallVector<int64_t>> baseStrides =
-      getIdentityStrides(baseType);
-  // TODO: Support non-identity source layouts by computing source strides from
+  // TODO: Support non-identity base layouts by computing base strides from
   // the layout map.
-  if (!baseStrides)
+  if (!rcBaseType.getLayout().isIdentity())
     return std::nullopt;
 
   CopyFromReinterCastInfo info;
-  SmallVector<bool> usedBaseDims(baseType.getRank(), false);
 
-  for (auto [resultDim, resultSize] : llvm::enumerate(resultType.getShape())) {
-    if (resultSize == 1)
-      continue;
-
-    // TODO: Support dynamic strides on copied dimensions.
-    if (ShapedType::isDynamic(rc.getStaticStrides()[resultDim]))
-      return std::nullopt;
-
-    // Each copied result dimension must map by stride to a source dimension
-    // whose static size >= result dimension size.
-    std::optional<unsigned> baseDim =
-        findSourceDimForResultDim(rc, static_cast<unsigned>(resultDim),
-                                  baseType, *baseStrides, usedBaseDims);
-    assert(baseDim &&
-           "static reinterpret_cast stride must map to an identity base "
-           "dimension");
-
-    usedBaseDims[*baseDim] = true;
-    info.loopDims.push_back(CopyLoopDimInfo{static_cast<unsigned>(resultDim),
-                                            *baseDim, resultSize});
-  }
+  // reinterpret_cast result dimensions must map to distinct base dimensions.
+  // The rewrite emits one loop per copied dimension and adds each IV to one
+  // base index.
+  if (!findBaseDimForResultDim(rc, info))
+    return std::nullopt;
 
-  ArrayRef<int64_t> offsets = rc.getStaticOffsets();
+  ArrayRef<int64_t> rcOffsets = rc.getStaticOffsets();
   // FIXME: Despite what `getStaticOffsets` implies, `reinterpret_cast` takes
   // only a single offset. That should be fixed at the op definition level.
-  assert(offsets.size() == 1 && "Expecting single offset");
-  if (!ShapedType::isDynamic(offsets[0])) {
-    // Static offset must delinearize to in-bounds source indices.
-    std::optional<SmallVector<int64_t>> offsetIndices =
-        delinearizeStaticOffset(rc, baseType, *baseStrides);
-    assert(offsetIndices &&
+  assert(rcOffsets.size() == 1 && "Expecting single offset");
+  // CASE 1: Static ReinterpretCast offset
+  if (!ShapedType::isDynamic(rcOffsets[0])) {
+    // Delinearize static ReinterpretCast offset as in-bounds indices (one for
+    // every base dimension).
+    std::optional<SmallVector<int64_t>> offsetIdxs =
+        delinearizeStaticRCOffset(rc);
+    assert(offsetIdxs &&
            "static reinterpret_cast offset must delinearize to in-bounds base "
            "indices");
 
-    for (const CopyLoopDimInfo &loopDim : info.loopDims) {
-      assert((*offsetIndices)[loopDim.baseDim] + loopDim.size <=
-                 baseType.getDimSize(loopDim.baseDim) &&
-             "reinterpret_cast metadata describes an invalid accessible "
-             "region");
-    }
-    info.staticOffsetIndices = std::move(offsetIndices);
+    assert(llvm::all_of(info.loopDims,
+                        [&](const CopyLoopDimInfo &loopDim) {
+                          return (*offsetIdxs)[loopDim.baseDim] +
+                                     loopDim.size <=
+                                 rcBaseType.getDimSize(loopDim.baseDim);
+                        }) &&
+           "reinterpret_cast metadata describes an invalid accessible region");
+    info.staticOffsetIdxs = std::move(offsetIdxs);
     return info;
   }
-
+  // CASE 2: Dynamic ReinterpretCast offset
   // Dynamic offsets are kept only when they can be used as a single base index.
   // TODO: Support dynamic offsets for copies with multiple loop dimensions by
   // delinearizing the offset into base start indices at runtime before adding
@@ -265,7 +254,7 @@ getCopyFromReinterCastInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
     // Dynamic scalar offsets cannot be delinearized statically. They can be
     // used directly only when the base has a single non-unit dimension to
     // receive them.
-    std::optional<unsigned> nonUnitDim = getSingleNonUnitDim(baseType);
+    std::optional<unsigned> nonUnitDim = getSingleNonUnitDim(rcBaseType);
     // TODO: Support scalar dynamic offsets into bases with multiple non-unit
     // dimensions by delinearizing the single accessed element offset at
     // runtime.
@@ -276,9 +265,12 @@ getCopyFromReinterCastInfo(memref::CopyOp op, memref::ReinterpretCastOp rc) {
     return info;
   }
 
-  unsigned baseDim = info.loopDims.front().baseDim;
-  info.dynamicOffsetDim =
-      (*baseStrides)[baseDim] == 1 ? baseDim : baseStrides->size() - 1;
+  unsigned rcBaseDim = info.loopDims.front().baseDim;
+  SmallVector<int64_t> rcBaseIdentityStrides =
+      computeStrides(rcBaseType.getShape());
+  info.dynamicOffsetDim = rcBaseIdentityStrides[rcBaseDim] == 1
+                              ? rcBaseDim
+                              : rcBaseIdentityStrides.size() - 1;
   return info;
 }
 
@@ -339,7 +331,7 @@ struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
     Value src = op.getSource();
     Value dst = rc.getSource();
 
-    MemRefType srcType = cast<MemRefType>(src.getType());
+    MemRefType cpSrcType = cast<MemRefType>(src.getType());
     MemRefType dstType = cast<MemRefType>(dst.getType());
 
     // Reuse common index constants across bounds, steps, and static offsets,
@@ -372,9 +364,8 @@ struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
     SmallVector<Value> baseStoreIndices = getZeroIndices(dstType.getRank());
     // Static offsets were already delinearized into base indices. Fill the
     // non-zero starting indices before creating loop bodies.
-    if (copyInfo->staticOffsetIndices) {
-      for (auto [idx, offset] :
-           llvm::enumerate(*copyInfo->staticOffsetIndices)) {
+    if (copyInfo->staticOffsetIdxs) {
+      for (auto [idx, offset] : llvm::enumerate(*copyInfo->staticOffsetIdxs)) {
         if (offset == 0)
           continue;
         baseStoreIndices[idx] = getOrCreateIndexConstant(offset);
@@ -384,12 +375,12 @@ struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
       // dimension selected by getCopyFromReinterCastInfo.
       assert(copyInfo->dynamicOffsetDim &&
              "expected dynamic offset dimension for dynamic offset");
-      SmallVector<OpFoldResult> offsets = rc.getMixedOffsets();
+      SmallVector<OpFoldResult> rcOffsets = rc.getMixedOffsets();
       // FIXME: Despite what `getMixedOffsets` implies, `reinterpret_cast` takes
       // only a single offset. That should be fixed at the op definition level.
-      assert(offsets.size() == 1 && "Expecting single offset");
+      assert(rcOffsets.size() == 1 && "Expecting single offset");
       baseStoreIndices[*copyInfo->dynamicOffsetDim] =
-          getValueOrCreateConstantIndexOp(rewriter, loc, offsets[0]);
+          getValueOrCreateConstantIndexOp(rewriter, loc, rcOffsets[0]);
     }
 
     // Scope for OpBuilder::InsertionGuard.
@@ -415,7 +406,7 @@ struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
 
       // Load indices are zero except for copied strided memref dimensions,
       // which use the corresponding loop induction variables.
-      SmallVector<Value> loadIndices = getZeroIndices(srcType.getRank());
+      SmallVector<Value> loadIndices = getZeroIndices(cpSrcType.getRank());
       unsigned loopIndex = 0;
       for (const CopyLoopDimInfo &loopDim : copyInfo->loopDims)
         loadIndices[loopDim.copyDim] = loopIvs[loopIndex++];
@@ -548,7 +539,7 @@ static bool isPureRankExpansionOrCollapsingRC(memref::ReinterpretCastOp rc) {
   if (!inputNonUnitDim || !outputNonUnitDim)
     return false;
 
-  // The source and result must either both have a single non-unit dimension
+  // The base and result must either both have a single non-unit dimension
   // or both be all-ones.
   if (inputNonUnitDim->allOnes != outputNonUnitDim->allOnes)
     return false;
@@ -592,7 +583,7 @@ static bool isPureRankExpansionOrCollapsingRC(memref::ReinterpretCastOp rc) {
 }
 
 /// Rewrites `memref.load` through a pure rank-only `reinterpret_cast` by
-/// mapping the load indices directly onto the source MemRef.
+/// mapping the load indices directly onto the base MemRef.
 
 /// Shape restriction gated by isPureRankExpansionOrCollapsingRC().
 ///
diff --git a/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir b/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
index 044e12cec42af..34678871e8cfe 100644
--- a/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
+++ b/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
@@ -297,6 +297,22 @@ func.func private @negative_copy_to_strided_non_identity_base(%src: memref<1x1xf
   return
 }
 
+// CHECK-LABEL: func.func private @negative_copy_to_strided_overlapping_result_dims(
+func.func private @negative_copy_to_strided_overlapping_result_dims(%src : memref<3x3xf32>,
+  %dst : memref<4x4xf32>) {
+  // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [0], sizes: [3, 3], strides: [1, 1]
+    : memref<4x4xf32> to memref<3x3xf32, strided<[1, 1]>>
+
+  // CHECK:      memref.copy %arg0, %reinterpret_cast
+  // CHECK-NOT:  memref.load
+  // CHECK-NOT:  memref.store
+  memref.copy %src, %reinterpret_cast
+    : memref<3x3xf32> to memref<3x3xf32, strided<[1, 1]>>
+  return
+}
+
 // CHECK-LABEL: func.func private @negative_copy_to_strided_rank_change(
 func.func private @negative_copy_to_strided_rank_change(%src : memref<2x3xf32>,
   %dst : memref<6xf32>) {

>From c11bb46b611739656cf1229dfc5191b416a53a96 Mon Sep 17 00:00:00 2001
From: Ioana Ghiban <ioana.ghiban at arm.com>
Date: Thu, 25 Jun 2026 09:41:58 +0200
Subject: [PATCH 6/8] Address third round of comments

---
 .../Transforms/ElideReinterpretCast.cpp       | 378 +++++++++---------
 .../MemRef/elide-reinterpret-cast.mlir        |  76 ++--
 2 files changed, 230 insertions(+), 224 deletions(-)

diff --git a/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp b/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
index 6d806b087bdb4..435600f58f7fa 100644
--- a/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
+++ b/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
@@ -35,141 +35,154 @@ namespace {
 // Copy Rewrite Helpers
 //===----------------------------------------------------------------------===//
 
-/// Per-dimension loop nest info.
-struct CopyLoopDimInfo {
-  unsigned copyDim;
-  unsigned baseDim;
-  int64_t size;
+/// Non-unit reinterpret_cast result dimension and the source dimension it
+/// advances through.
+struct NonUnitDimAssocMapForRC {
+  unsigned resultDimPos;
+  unsigned sourceDimPos;
 };
 
-/// Rewrite info from reinterpret_cast layout, captured after passing legality
-/// checks.
-struct CopyFromReinterCastInfo {
-  // Loop bounds that non-scalar loads "lower" to
-  SmallVector<CopyLoopDimInfo> loopDims;
-  // Deinearized offsets to in-bounds base indices.
-  std::optional<SmallVector<int64_t>> staticOffsetIdxs;
-  // reinterpret_cast dynamic offsets only supported for single non-unit
-  // dimension base, stored here to receive them.
-  std::optional<unsigned> dynamicOffsetDim;
+/// Copy-relevant information derived from a reinterpret_cast.
+struct AssocMapAndOffsetsForRC {
+  // Non-unit dimensions of the reinterpret_cast result.
+  SmallVector<NonUnitDimAssocMapForRC> assocMap;
+  // Delinearized offsets to in-bounds reinterpret_cast source indices.
+  // Optional since it is only supported for static offsets.
+  std::optional<SmallVector<int64_t>> delinearizedOffsets;
 };
 
-/// Maps non-unit reinterpret_cast result dimensions to distinct base
-/// dimensions.
-static bool findBaseDimForResultDim(memref::ReinterpretCastOp rc,
-                                    CopyFromReinterCastInfo &info) {
+/// Records the reinterpret_cast result dimensions that span more than one
+/// element and maps each one to its corresponding source dimension.
+static bool findSourceDimForResultDim(memref::ReinterpretCastOp rc,
+                                      AssocMapAndOffsetsForRC &mapAndOffs) {
   MemRefType resType = dyn_cast<MemRefType>(rc.getType());
-  MemRefType baseType = dyn_cast<MemRefType>(rc.getSource().getType());
-  SmallVector<int64_t> baseIdentityStrides =
-      computeStrides(baseType.getShape());
+  MemRefType srcType = dyn_cast<MemRefType>(rc.getSource().getType());
+  assert(srcType.getLayout().isIdentity() &&
+         "Expecting identity source layout.");
 
-  // Each result loop IV is added directly to one base index. Reusing a base
-  // dimension would require delinearizing the combined linear offset.
-  SmallVector<bool> usedBaseDims(baseType.getRank(), false);
+  SmallVector<int64_t> srcIdentityStrides = computeStrides(srcType.getShape());
+
+  // Reusing a source dimension would require delinearizing the combined linear
+  // offset, which is TODO.
+  SmallVector<bool> usedSrcDims(srcType.getRank(), false);
 
-  // Populate one loop-dimension entry for each non-unit result dimension.
   for (auto [resultDim, resultSize] : llvm::enumerate(resType.getShape())) {
     if (resultSize == 1)
       continue;
 
-    // TODO: Support dynamic strides on copied dimensions.
+    // TODO: Support dynamic strides on non-unit result dimensions.
     if (ShapedType::isDynamic(rc.getStaticStrides()[resultDim]))
       return false;
 
     int64_t resultStride = rc.getStaticStrides()[resultDim];
-    std::optional<unsigned> baseDim;
-    // Find an unused base dimension with matching stride and enough elements.
-    for (auto [idx, stride] : llvm::enumerate(baseIdentityStrides)) {
-      if (usedBaseDims[idx] || stride != resultStride ||
-          baseType.getDimSize(idx) < resultSize)
+    std::optional<unsigned> srcDim;
+    // Find an unused source dimension with matching stride and enough elements.
+    for (auto [idx, stride] : llvm::enumerate(srcIdentityStrides)) {
+      if (usedSrcDims[idx] || stride != resultStride ||
+          srcType.getDimSize(idx) < resultSize)
         continue;
 
-      if (!baseDim || baseType.getDimSize(idx) < baseType.getDimSize(*baseDim))
-        baseDim = idx;
+      if (!srcDim || srcType.getDimSize(idx) < srcType.getDimSize(*srcDim))
+        srcDim = idx;
     }
-    if (!baseDim)
+    if (!srcDim)
       return false;
 
-    usedBaseDims[*baseDim] = true;
-    info.loopDims.push_back(CopyLoopDimInfo{static_cast<unsigned>(resultDim),
-                                            *baseDim, resultSize});
+    usedSrcDims[*srcDim] = true;
+    mapAndOffs.assocMap.push_back(
+        NonUnitDimAssocMapForRC{static_cast<unsigned>(resultDim), *srcDim});
   }
   return true;
 }
 
-/// Returns base indices for a static reinterpret_cast offset.
+/// Returns source indices for a static reinterpret_cast offset of an
+/// identity-layout source.
 static std::optional<SmallVector<int64_t>>
 delinearizeStaticRCOffset(memref::ReinterpretCastOp rc) {
   ArrayRef<int64_t> rcOffsets = rc.getStaticOffsets();
   // FIXME: Despite what `getStaticOffsets` implies, `reinterpret_cast` takes
   // only a single offset. That should be fixed at the op definition level.
   assert(rcOffsets.size() == 1 && "Expecting single offset");
-  assert(!ShapedType::isDynamic(rcOffsets[0]) && "expected static offset");
-
-  if (rcOffsets[0] < 0)
-    return std::nullopt;
+  assert(ShapedType::isStatic(rcOffsets[0]) && "expected static offset");
+
+  assert(rcOffsets[0] >= 0 &&
+         "static reinterpret_cast offset must be non-negative");
+
+  MemRefType srcType = dyn_cast<MemRefType>(rc.getSource().getType());
+  assert(srcType.getLayout().isIdentity() &&
+         "Expecting identity source layout.");
+  if (srcType.getRank() == 0) {
+    assert(rcOffsets[0] == 0 &&
+           "non-zero static offset is invalid for rank-0 source memref");
+    return SmallVector<int64_t>{};
+  }
 
-  MemRefType baseType = dyn_cast<MemRefType>(rc.getSource().getType());
-  SmallVector<int64_t> indices(baseType.getRank(), 0);
+  SmallVector<int64_t> offsetIdxs(srcType.getRank(), 0);
   int64_t remainder = rcOffsets[0];
-  SmallVector<int64_t> baseStrides = computeStrides(baseType.getShape());
-  for (auto [idx, stride] : llvm::enumerate(baseStrides)) {
-    indices[idx] = remainder / stride;
-    if (indices[idx] >= baseType.getDimSize(idx))
-      return std::nullopt;
+  SmallVector<int64_t> srcStrides = computeStrides(srcType.getShape());
+  // Convert the linear reinterpret_cast offset to per-dimension source starting
+  // indices.
+  for (auto [dim, stride] : llvm::enumerate(srcStrides)) {
+    offsetIdxs[dim] = remainder / stride;
+    assert(offsetIdxs[dim] < srcType.getDimSize(dim) &&
+           "static reinterpret_cast offset must delinearize to in-bounds "
+           "source indices");
     remainder %= stride;
   }
 
-  if (remainder != 0)
-    return std::nullopt;
-  return indices;
+  assert(remainder == 0 &&
+         "Assuming identity source layout, the trailing stride == 1 "
+         "so, the remainder should be 0 at the end of index calculation.");
+  return offsetIdxs;
 }
 
-/// Returns the dimension whose static size is not one if it is unique.
+/// Returns the unique non-unit dim or nullopt of # non-unit-dims != 1.
 static std::optional<unsigned> getSingleNonUnitDim(MemRefType type) {
   assert(type.hasStaticShape() && "expected static shape");
   ArrayRef<int64_t> shape = type.getShape();
-  if (shape.empty())
+
+  // Find all non-unit dims
+  auto nonUnitDims = llvm::make_filter_range(
+      llvm::enumerate(shape), [](auto it) { return it.value() != 1; });
+
+  // Expect single non-unit dims
+  if (llvm::range_size(nonUnitDims) != 1)
     return std::nullopt;
 
-  std::optional<unsigned> nonUnitDim;
-  for (auto [idx, dim] : llvm::enumerate(shape)) {
-    if (dim == 1)
-      continue;
-    if (nonUnitDim)
-      return std::nullopt;
-    nonUnitDim = idx;
-  }
-  return nonUnitDim;
+  // Return the index of the unique non-unit dim.
+  return (*nonUnitDims.begin()).index();
 }
 
-/// Builds the index mapping needed to replace a copy into a reinterpret_cast
-/// strided memref with scalar stores into the reinterpret_cast base.
+/// Returns the copy-relevant reinterpret_cast information: non-unit result
+/// dimensions, their source-dimension mapping, and optional source starting
+/// indices for a static offset.
 ///
 /// Examples that return rewrite info:
 ///
-///   // Scalar-shaped copy. There are no copied non-unit dimensions, so dynamic
-///   // strides in the strided memref do not affect index mapping.
+///   // Scalar-shaped copy into a source with at most one non-unit dimension.
+///   There are
+///   // no non-unit result dimensions, so dynamic strides in the strided memref
+///   // do not affect index mapping.
 ///   copy memref<1 x ... x 1 x f32>
-///     to reinterpret_cast memref<base-shape>
+///     to reinterpret_cast memref<source-shape>
 ///       to memref<1 x ... x 1 x f32, strided<[?, ..., ?], offset: ?>>
 ///
 ///   // Effectively-1D copy. The single non-unit strided memref dimension is
-///   // mapped to an identity-layout base dimension by its static stride.
+///   // mapped to an identity-layout source dimension by its static stride.
 ///   copy memref<1 x ... x N x ... x 1 x f32>
-///     to reinterpret_cast memref<base-shape>
+///     to reinterpret_cast memref<source-shape>
 ///       to memref<1 x ... x N x ... x 1 x f32, strided<[..., S, ...]>>
 ///
 ///   // Multidimensional copy with static offset. Each non-unit strided memref
 ///   // dimension is mapped independently by its static stride.
 ///   copy memref<1 x ... x N_0 x ... x N_K x ... x 1 x f32>
-///     to reinterpret_cast memref<base-shape>
+///     to reinterpret_cast memref<source-shape>
 ///       to memref<1 x ... x N_0 x ... x N_K x ... x 1 x f32,
 ///                 strided<[..., S_0, ..., S_1, ...], offset: O>>
 ///
 /// Examples that return no info:
 ///
-///   // Dynamic stride on a copied strided memref dimension.
+///   // Dynamic stride on a non-unit strided memref dimension.
 ///   copy memref<1xNxf32>
 ///     to reinterpret_cast memref<1xNxMxf32>
 ///       to memref<1xNxf32, strided<[?, ?]>>
@@ -178,100 +191,73 @@ static std::optional<unsigned> getSingleNonUnitDim(MemRefType type) {
 ///   copy memref<1xNxKxf32>
 ///     to reinterpret_cast memref<1xNxMxf32>
 ///       to memref<1xNxKxf32, strided<[N*M, M, 1], offset: ?>>
-static std::optional<CopyFromReinterCastInfo>
-getCopyFromReinterCastInfo(memref::CopyOp copy, memref::ReinterpretCastOp rc) {
-  MemRefType cpSrcType = dyn_cast<MemRefType>(copy.getSource().getType());
-  MemRefType rcBaseType = dyn_cast<MemRefType>(rc.getSource().getType());
-  MemRefType rcResType = dyn_cast<MemRefType>(rc.getType());
+static std::optional<AssocMapAndOffsetsForRC>
+getAssocMapAndOffsetsForRC(memref::ReinterpretCastOp rc) {
+  MemRefType srcType = dyn_cast<MemRefType>(rc.getSource().getType());
+  MemRefType resType = dyn_cast<MemRefType>(rc.getType());
 
   // Ranked memref types are required to statically build load/store index
   // lists.
-  if (!cpSrcType || !rcBaseType || !rcResType)
-    return std::nullopt;
-
-  if (cpSrcType.getShape() != rcResType.getShape())
+  if (!srcType || !resType)
     return std::nullopt;
 
-  // TODO: Support rank-modifying reinterpret_casts by converting the
-  // strided memref indices to base indices. For example, a copy to
-  // a strided memref<2x3xf32> of base memref<6xf32> needs to linearize the
-  // strided memref indices as `i * 3 + j`, then combine that with the
-  // reinterpret_cast offset before indexing the rank-1 base memref.
-  if (rcBaseType.getRank() != rcResType.getRank())
+  // TODO: Support rank-modifying reinterpret_casts
+  if (srcType.getRank() != resType.getRank())
     return std::nullopt;
 
   // TODO: Support dynamic shapes with mixed size operands as loop bounds.
-  if (!(cpSrcType.hasStaticShape() && rcBaseType.hasStaticShape() &&
-        rcResType.hasStaticShape()))
+  if (!(srcType.hasStaticShape() && resType.hasStaticShape()))
     return std::nullopt;
 
-  // TODO: Support non-identity base layouts by computing base strides from
+  // TODO: Support non-identity source layouts by computing source strides from
   // the layout map.
-  if (!rcBaseType.getLayout().isIdentity())
+  if (!srcType.getLayout().isIdentity())
     return std::nullopt;
 
-  CopyFromReinterCastInfo info;
+  AssocMapAndOffsetsForRC mapAndOffs;
 
-  // reinterpret_cast result dimensions must map to distinct base dimensions.
-  // The rewrite emits one loop per copied dimension and adds each IV to one
-  // base index.
-  if (!findBaseDimForResultDim(rc, info))
+  // reinterpret_cast result dimensions must map to distinct source dimensions.
+  if (!findSourceDimForResultDim(rc, mapAndOffs))
     return std::nullopt;
 
   ArrayRef<int64_t> rcOffsets = rc.getStaticOffsets();
   // FIXME: Despite what `getStaticOffsets` implies, `reinterpret_cast` takes
   // only a single offset. That should be fixed at the op definition level.
   assert(rcOffsets.size() == 1 && "Expecting single offset");
-  // CASE 1: Static ReinterpretCast offset
-  if (!ShapedType::isDynamic(rcOffsets[0])) {
+  // Static ReinterpretCast offset
+  if (ShapedType::isStatic(rcOffsets[0])) {
     // Delinearize static ReinterpretCast offset as in-bounds indices (one for
-    // every base dimension).
-    std::optional<SmallVector<int64_t>> offsetIdxs =
-        delinearizeStaticRCOffset(rc);
-    assert(offsetIdxs &&
-           "static reinterpret_cast offset must delinearize to in-bounds base "
-           "indices");
-
-    assert(llvm::all_of(info.loopDims,
-                        [&](const CopyLoopDimInfo &loopDim) {
-                          return (*offsetIdxs)[loopDim.baseDim] +
-                                     loopDim.size <=
-                                 rcBaseType.getDimSize(loopDim.baseDim);
-                        }) &&
-           "reinterpret_cast metadata describes an invalid accessible region");
-    info.staticOffsetIdxs = std::move(offsetIdxs);
-    return info;
+    // every source dimension).
+    mapAndOffs.delinearizedOffsets = delinearizeStaticRCOffset(rc);
+    assert(
+        mapAndOffs.delinearizedOffsets &&
+        "static reinterpret_cast offset must delinearize to in-bounds source "
+        "indices");
+
+    assert(
+        llvm::all_of(
+            mapAndOffs.assocMap,
+            [&](const NonUnitDimAssocMapForRC &assocMap) {
+              return (*mapAndOffs.delinearizedOffsets)[assocMap.sourceDimPos] +
+                         resType.getDimSize(assocMap.resultDimPos) <=
+                     srcType.getDimSize(assocMap.sourceDimPos);
+            }) &&
+        "reinterpret_cast metadata describes an invalid accessible region");
+    return mapAndOffs;
   }
-  // CASE 2: Dynamic ReinterpretCast offset
-  // Dynamic offsets are kept only when they can be used as a single base index.
-  // TODO: Support dynamic offsets for copies with multiple loop dimensions by
-  // delinearizing the offset into base start indices at runtime before adding
-  // loop IVs.
-  if (info.loopDims.size() > 1)
-    return std::nullopt;
 
-  if (info.loopDims.empty()) {
-    // Dynamic scalar offsets cannot be delinearized statically. They can be
-    // used directly only when the base has a single non-unit dimension to
-    // receive them.
-    std::optional<unsigned> nonUnitDim = getSingleNonUnitDim(rcBaseType);
-    // TODO: Support scalar dynamic offsets into bases with multiple non-unit
-    // dimensions by delinearizing the single accessed element offset at
-    // runtime.
-    if (!nonUnitDim)
-      return std::nullopt;
-
-    info.dynamicOffsetDim = *nonUnitDim;
-    return info;
-  }
+  // Dynamic ReinterpretCast offset.
+  // TODO: Support dynamic offsets into sources with multiple non-unit
+  // dimensions by delinearizing the offset into source start indices at runtime
+  // before adding loop IVs.
+  if (mapAndOffs.assocMap.size() > 1)
+    return std::nullopt;
+  // Only sources with a single non-unit dimension can receive a dynamic offset
+  // directly.
+  if (!getSingleNonUnitDim(srcType))
+    return std::nullopt;
 
-  unsigned rcBaseDim = info.loopDims.front().baseDim;
-  SmallVector<int64_t> rcBaseIdentityStrides =
-      computeStrides(rcBaseType.getShape());
-  info.dynamicOffsetDim = rcBaseIdentityStrides[rcBaseDim] == 1
-                              ? rcBaseDim
-                              : rcBaseIdentityStrides.size() - 1;
-  return info;
+  return mapAndOffs;
 }
 
 /// Rewrites supported copy operations through `memref.reinterpret_cast` to
@@ -315,23 +301,25 @@ struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
 
   LogicalResult matchAndRewrite(memref::CopyOp op,
                                 PatternRewriter &rewriter) const final {
+    Value src = op.getSource();
+    MemRefType cpSrcType = cast<MemRefType>(src.getType());
+    if (!cpSrcType || !cpSrcType.hasStaticShape())
+      return rewriter.notifyMatchFailure(
+          op, "only ranked, static copy sources are supported.");
     Value rcOutput = op.getTarget();
     auto rc = rcOutput.getDefiningOp<memref::ReinterpretCastOp>();
     if (!rc)
       return rewriter.notifyMatchFailure(
           op, "target is not a memref.reinterpret_cast");
 
-    std::optional<CopyFromReinterCastInfo> copyInfo =
-        getCopyFromReinterCastInfo(op, rc);
-    if (!copyInfo)
+    std::optional<AssocMapAndOffsetsForRC> mapAndOffs =
+        getAssocMapAndOffsetsForRC(rc);
+    if (!mapAndOffs)
       return rewriter.notifyMatchFailure(
           op, "reinterpret_cast does not match scalar or loop copy region");
 
     Location loc = op.getLoc();
-    Value src = op.getSource();
     Value dst = rc.getSource();
-
-    MemRefType cpSrcType = cast<MemRefType>(src.getType());
     MemRefType dstType = cast<MemRefType>(dst.getType());
 
     // Reuse common index constants across bounds, steps, and static offsets,
@@ -346,40 +334,48 @@ struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
       }
       return arith::ConstantIndexOp::create(rewriter, loc, value);
     };
-    auto getZeroIndices = [&](int64_t rank) {
-      SmallVector<Value> indices;
-      indices.reserve(rank);
+    auto getZeroIdxs = [&](int64_t rank) {
+      SmallVector<Value> idxs;
+      idxs.reserve(rank);
       if (rank != 0)
-        indices.append(rank, getOrCreateIndexConstant(0));
-      return indices;
+        idxs.append(rank, getOrCreateIndexConstant(0));
+      return idxs;
     };
 
-    // Create all loop bounds before building the loop nest. Otherwise an
-    // inner-loop bound can be inserted inside an outer loop body.
+    // Create loop bounds before moving the insertion point into the loop nest,
+    // so loop-invariant constants are emitted outside the generated loops.
     SmallVector<Value> upperBounds;
-    upperBounds.reserve(copyInfo->loopDims.size());
-    for (const CopyLoopDimInfo &loopDim : copyInfo->loopDims)
-      upperBounds.push_back(getOrCreateIndexConstant(loopDim.size));
-
-    SmallVector<Value> baseStoreIndices = getZeroIndices(dstType.getRank());
-    // Static offsets were already delinearized into base indices. Fill the
-    // non-zero starting indices before creating loop bodies.
-    if (copyInfo->staticOffsetIdxs) {
-      for (auto [idx, offset] : llvm::enumerate(*copyInfo->staticOffsetIdxs)) {
+    upperBounds.reserve(mapAndOffs->assocMap.size());
+    MemRefType rcResType = dyn_cast<MemRefType>(rc.getType());
+    for (const NonUnitDimAssocMapForRC &assocMap : mapAndOffs->assocMap)
+      upperBounds.push_back(getOrCreateIndexConstant(
+          rcResType.getDimSize(assocMap.resultDimPos)));
+
+    SmallVector<Value> rcSrcStoreIdxs = getZeroIdxs(dstType.getRank());
+    std::optional<unsigned> srcNonUnitDimPos;
+    // Static offset has been delinearized in function gating rewrite.
+    if (mapAndOffs->delinearizedOffsets) {
+      for (auto [idx, offset] :
+           llvm::enumerate(*mapAndOffs->delinearizedOffsets)) {
         if (offset == 0)
           continue;
-        baseStoreIndices[idx] = getOrCreateIndexConstant(offset);
+        rcSrcStoreIdxs[idx] = getOrCreateIndexConstant(offset);
       }
     } else {
-      // Supported dynamic offsets are used directly in exactly one base
-      // dimension selected by getCopyFromReinterCastInfo.
-      assert(copyInfo->dynamicOffsetDim &&
-             "expected dynamic offset dimension for dynamic offset");
+      // Without runtime delinearization, use the dynamic offset directly only
+      // when the source has a single non-unit dimension.
+      assert(mapAndOffs->assocMap.size() <= 1 &&
+             "Expecting single non-unit dimension mapping.");
+      srcNonUnitDimPos = getSingleNonUnitDim(dstType);
+      assert(srcNonUnitDimPos &&
+             "Expecting single non-unit dimension source to receive the "
+             "dynamic offset.");
+
       SmallVector<OpFoldResult> rcOffsets = rc.getMixedOffsets();
       // FIXME: Despite what `getMixedOffsets` implies, `reinterpret_cast` takes
       // only a single offset. That should be fixed at the op definition level.
       assert(rcOffsets.size() == 1 && "Expecting single offset");
-      baseStoreIndices[*copyInfo->dynamicOffsetDim] =
+      rcSrcStoreIdxs[*srcNonUnitDimPos] =
           getValueOrCreateConstantIndexOp(rewriter, loc, rcOffsets[0]);
     }
 
@@ -392,11 +388,10 @@ struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
         lowerBound = getOrCreateIndexConstant(0);
         step = getOrCreateIndexConstant(1);
       }
-
       SmallVector<Value> loopIvs;
-      loopIvs.reserve(copyInfo->loopDims.size());
+      loopIvs.reserve(mapAndOffs->assocMap.size());
 
-      // Build one nested loop per non-unit copied strided memref dimension.
+      // Build one nested loop per non-unit strided memref dimension.
       for (Value upperBound : upperBounds) {
         scf::ForOp loop =
             scf::ForOp::create(rewriter, loc, lowerBound, upperBound, step);
@@ -404,31 +399,32 @@ struct CopyToLoadAndStore : public OpRewritePattern<memref::CopyOp> {
         rewriter.setInsertionPointToStart(loop.getBody());
       }
 
-      // Load indices are zero except for copied strided memref dimensions,
+      // Load indices are zero except for non-unit strided memref dimensions,
       // which use the corresponding loop induction variables.
-      SmallVector<Value> loadIndices = getZeroIndices(cpSrcType.getRank());
+      SmallVector<Value> loadIdxs = getZeroIdxs(cpSrcType.getRank());
       unsigned loopIndex = 0;
-      for (const CopyLoopDimInfo &loopDim : copyInfo->loopDims)
-        loadIndices[loopDim.copyDim] = loopIvs[loopIndex++];
+      for (const NonUnitDimAssocMapForRC &assocMap : mapAndOffs->assocMap)
+        loadIdxs[assocMap.resultDimPos] = loopIvs[loopIndex++];
 
-      // Store indices start from the offset-derived base indices. Add each loop
-      // IV to the mapped base dimension.
-      SmallVector<Value> storeIndices(baseStoreIndices);
+      // Store indices start from the offset-derived source indices. Add each
+      // loop IV to the mapped source dimension.
+      SmallVector<Value> storeIdxs(rcSrcStoreIdxs);
       loopIndex = 0;
-      for (const CopyLoopDimInfo &loopDim : copyInfo->loopDims) {
+      for (const NonUnitDimAssocMapForRC &assocMap : mapAndOffs->assocMap) {
         Value iv = loopIvs[loopIndex++];
-        if (storeIndices[loopDim.baseDim] == getOrCreateIndexConstant(0)) {
-          storeIndices[loopDim.baseDim] = iv;
+        // Add each IV to one source index.
+        if (storeIdxs[assocMap.sourceDimPos] == getOrCreateIndexConstant(0)) {
+          storeIdxs[assocMap.sourceDimPos] = iv;
         } else {
-          storeIndices[loopDim.baseDim] = arith::AddIOp::create(
-              rewriter, loc, storeIndices[loopDim.baseDim], iv);
+          storeIdxs[assocMap.sourceDimPos] = arith::AddIOp::create(
+              rewriter, loc, storeIdxs[assocMap.sourceDimPos], iv);
         }
       }
 
       // Emit the scalar load/store at the innermost loop body, or directly at
       // the original copy location for scalar copies.
-      Value val = memref::LoadOp::create(rewriter, loc, src, loadIndices);
-      memref::StoreOp::create(rewriter, loc, val, dst, storeIndices);
+      Value val = memref::LoadOp::create(rewriter, loc, src, loadIdxs);
+      memref::StoreOp::create(rewriter, loc, val, dst, storeIdxs);
     }
 
     // If the only user of `rc` is the current Op (which is about to be erased),
@@ -709,7 +705,11 @@ struct ElideReinterpretCastPass
       auto rc = op.getTarget().getDefiningOp<memref::ReinterpretCastOp>();
       if (!rc)
         return true;
-      return !getCopyFromReinterCastInfo(op, rc);
+      // Pattern applies only when the copy source shape is static and the
+      // reinterpret_cast result can be mapped back to base memref indices.
+      MemRefType cpSrcType = dyn_cast<MemRefType>(op.getSource().getType());
+      return !(cpSrcType && cpSrcType.hasStaticShape() &&
+               getAssocMapAndOffsetsForRC(rc));
     });
     target.addDynamicallyLegalOp<memref::LoadOp>([](memref::LoadOp op) {
       auto rc = op.getMemRef().getDefiningOp<memref::ReinterpretCastOp>();
diff --git a/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir b/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
index 34678871e8cfe..4a879a916c625 100644
--- a/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
+++ b/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
@@ -92,7 +92,6 @@ func.func private @copy_to_strided_dynamic_stride(%stride0: index,
   // CHECK-NOT:  memref.copy
   // CHECK:      %[[C0:.*]] = arith.constant 0 : index
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]]] : memref<1x1xf32>
-  /// Dynamic offset used in store
   // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]]] : memref<1x108xf32>
   memref.copy %src, %reinterpret_cast
     : memref<1x1xf32>
@@ -117,10 +116,10 @@ func.func private @copy_to_strided_rank0(%src : memref<f32>, %dst : memref<f32>)
   return
 }
 
-// CHECK-LABEL: func.func private @copy_to_strided_0d_2d_base(
+// CHECK-LABEL: func.func private @copy_to_strided_0d_base_2d(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x1x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
-func.func private @copy_to_strided_0d_2d_base(
+func.func private @copy_to_strided_0d_base_2d(
   %src : memref<1x1x1xf32>, %dst : memref<1x33x42xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -190,11 +189,11 @@ func.func private @copy_to_strided_1d_vector_nonzero_offset(
   return
 }
 
-// CHECK-LABEL: func.func private @copy_to_strided_1d_vector_dynamic_offset_in_loop_dim(
+// CHECK-LABEL: func.func private @copy_to_strided_1d_vector_1d_base_dynamic_offset(
 // CHECK-SAME:   %[[OFF:.*]]: index
 // CHECK-SAME:   %[[SRC:.*]]: memref<4xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<42xf32>
-func.func private @copy_to_strided_1d_vector_dynamic_offset_in_loop_dim(
+func.func private @copy_to_strided_1d_vector_1d_base_dynamic_offset(
   %offset : index, %src : memref<4xf32>, %dst : memref<42xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -216,34 +215,6 @@ func.func private @copy_to_strided_1d_vector_dynamic_offset_in_loop_dim(
   return
 }
 
-// CHECK-LABEL: func.func private @copy_to_strided_1d_vector_dynamic_offset_not_in_loop_dim(
-// CHECK-SAME:   %[[OFF:.*]]: index
-// CHECK-SAME:   %[[SRC:.*]]: memref<1x3x1xf32>
-// CHECK-SAME:   %[[DST:.*]]: memref<1x3x11xf32>
-func.func private @copy_to_strided_1d_vector_dynamic_offset_not_in_loop_dim(
-  %offset : index, %src : memref<1x3x1xf32>,
-  %dst : memref<1x3x11xf32>) {
-  // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [%offset], sizes: [1, 3, 1], strides: [33, 11, 1]
-    : memref<1x3x11xf32>
-      to memref<1x3x1xf32, strided<[33, 11, 1], offset: ?>>
-
-  // CHECK-NOT:  memref.copy
-  // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
-  // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
-  // CHECK-DAG:  %[[C3:.*]] = arith.constant 3 : index
-  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C3]] step %[[C1]] {
-  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x3x1xf32>
-  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[OFF]]] : memref<1x3x11xf32>
-  // CHECK:      }
-  memref.copy %src, %reinterpret_cast
-    : memref<1x3x1xf32>
-      to memref<1x3x1xf32, strided<[33, 11, 1], offset: ?>>
-  // CHECK-NOT:  memref.copy
-  return
-}
-
 // CHECK-LABEL: func.func private @copy_to_strided_2d_vector_nonzero_offset(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x3x4xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x3x11xf32>
@@ -361,8 +332,24 @@ func.func private @negative_copy_to_strided_dynamic_rc_shapes(%dim : index,
   return
 }
 
-// CHECK-LABEL: func.func private @negative_copy_to_strided_dynamic_offset_multi_dim_base(
-func.func private @negative_copy_to_strided_dynamic_offset_multi_dim_base(
+// CHECK-LABEL: func.func private @negative_copy_to_strided_unranked_rc_base(
+func.func private @negative_copy_to_strided_unranked_rc_base(
+  %src : memref<4xf32>, %dst : memref<*xf32>) {
+  // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [0], sizes: [4], strides: [1]
+    : memref<*xf32> to memref<4xf32>
+
+  // CHECK:      memref.copy %arg0, %reinterpret_cast
+  // CHECK-NOT:  memref.load
+  // CHECK-NOT:  memref.store
+  memref.copy %src, %reinterpret_cast
+    : memref<4xf32> to memref<4xf32>
+  return
+}
+
+// CHECK-LABEL: func.func private @negative_copy_to_strided_0d_base_2d_dynamic_offset(
+func.func private @negative_copy_to_strided_0d_base_2d_dynamic_offset(
   %offset : index, %src : memref<1x1xf32>, %dst : memref<4x8xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
   %reinterpret_cast = memref.reinterpret_cast %dst
@@ -378,6 +365,25 @@ func.func private @negative_copy_to_strided_dynamic_offset_multi_dim_base(
   return
 }
 
+// CHECK-LABEL: func.func private @negative_copy_to_strided_1d_base_2d_dynamic_offset(
+func.func private @negative_copy_to_strided_1d_base_2d_dynamic_offset(
+  %offset : index, %src : memref<1x3x1xf32>,
+  %dst : memref<1x3x11xf32>) {
+  // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [%offset], sizes: [1, 3, 1], strides: [33, 11, 1]
+    : memref<1x3x11xf32>
+      to memref<1x3x1xf32, strided<[33, 11, 1], offset: ?>>
+
+  // CHECK:      memref.copy %arg1, %reinterpret_cast
+  // CHECK-NOT:  memref.load
+  // CHECK-NOT:  memref.store
+  memref.copy %src, %reinterpret_cast
+    : memref<1x3x1xf32>
+      to memref<1x3x1xf32, strided<[33, 11, 1], offset: ?>>
+  return
+}
+
 // CHECK-LABEL: func.func private @negative_copy_to_strided_2d_dynamic_offset(
 func.func private @negative_copy_to_strided_2d_dynamic_offset(
   %offset : index, %src : memref<1x3x4xf32>,

>From 8c90ec715552457fc2676af41000a7b008719197 Mon Sep 17 00:00:00 2001
From: Ioana Ghiban <ioana.ghiban at arm.com>
Date: Fri, 26 Jun 2026 17:50:06 +0200
Subject: [PATCH 7/8] Fixup tests

---
 .../MemRef/elide-reinterpret-cast.mlir        | 245 +++++++++++-------
 1 file changed, 145 insertions(+), 100 deletions(-)

diff --git a/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir b/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
index 4a879a916c625..eaa823e4afd3d 100644
--- a/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
+++ b/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
@@ -5,14 +5,16 @@
 // Positive tests
 //===----------------------------------------------------------------------===//
 
-// CHECK-LABEL: func.func private @copy_to_strided_zero_offset(
+/// Effectively copied scalar within a MemRef with rank >= 0
+/// to practically a 1D array within a MemRef with rank >= 1
+// CHECK-LABEL: func.func private @copy_scalar_into_1D_strided_zero_offset(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x108xf32>
-func.func private @copy_to_strided_zero_offset(%src : memref<1x1xf32>,
+func.func private @copy_scalar_into_1D_strided_zero_offset(%src : memref<1x1xf32>,
   %dst : memref<1x108xf32>) {
   /// reinterpret_cast removed
   // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [1, 1], strides: [1, 1]
     : memref<1x108xf32> to memref<1x1xf32>
 
@@ -21,19 +23,19 @@ func.func private @copy_to_strided_zero_offset(%src : memref<1x1xf32>,
   // CHECK:      %[[C0:.*]] = arith.constant 0 : index
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]]] : memref<1x1xf32>
   // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]]] : memref<1x108xf32>
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<1x1xf32> to memref<1x1xf32>
   // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @copy_to_strided_nonzero_offset(
+// CHECK-LABEL: func.func private @copy_scalar_into_1D_strided_nonzero_offset(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x108xf32>
-func.func private @copy_to_strided_nonzero_offset(%src : memref<1x1xf32>,
+func.func private @copy_scalar_into_1D_strided_nonzero_offset(%src : memref<1x1xf32>,
   %dst : memref<1x108xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [1], sizes: [1, 1], strides: [1, 1]
     : memref<1x108xf32>
       to memref<1x1xf32, strided<[1, 1], offset: 1>>
@@ -43,21 +45,21 @@ func.func private @copy_to_strided_nonzero_offset(%src : memref<1x1xf32>,
   // CHECK:      %[[C1:.*]] = arith.constant 1 : index
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]]] : memref<1x1xf32>
   // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C1]]] : memref<1x108xf32>
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<1x1xf32>
       to memref<1x1xf32, strided<[1, 1], offset: 1>>
   // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @copy_to_strided_dynamic_offset(
+// CHECK-LABEL: func.func private @copy_scalar_into_1D_strided_dynamic_offset(
 // CHECK-SAME:   %[[OFF:.*]]: index
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x108xf32>
-func.func private @copy_to_strided_dynamic_offset(%offset: index, %src : memref<1x1xf32>,
+func.func private @copy_scalar_into_1D_strided_dynamic_offset(%offset: index, %src : memref<1x1xf32>,
   %dst : memref<1x108xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [%offset], sizes: [1, 1], strides: [1, 1]
     : memref<1x108xf32>
       to memref<1x1xf32, strided<[1, 1], offset: ?>>
@@ -68,7 +70,7 @@ func.func private @copy_to_strided_dynamic_offset(%offset: index, %src : memref<
   // CHECK-SAME: : memref<1x1xf32>
   /// Dynamic offset used in store
   // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[OFF]]] : memref<1x108xf32>
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<1x1xf32>
       to memref<1x1xf32, strided<[1, 1], offset: ?>>
   // CHECK-NOT:  memref.copy
@@ -76,15 +78,15 @@ func.func private @copy_to_strided_dynamic_offset(%offset: index, %src : memref<
 }
 
 // Dynamic strides are irrelevant because all strided memref indices are zero.
-// CHECK-LABEL: func.func private @copy_to_strided_dynamic_stride(
+// CHECK-LABEL: func.func private @copy_scalar_into_1D_strided_dynamic_stride(
 // CHECK-SAME:   %[[STR0:[A-Za-z][A-Za-z0-9-]*]]: index
 // CHECK-SAME:   %[[STR1:[A-Za-z][A-Za-z0-9-]*]]: index
 // CHECK-SAME:   %[[SRC:[A-Za-z][A-Za-z0-9-]*]]: memref<1x1xf32>
 // CHECK-SAME:   %[[DST:[A-Za-z][A-Za-z0-9-]*]]: memref<1x108xf32>
-func.func private @copy_to_strided_dynamic_stride(%stride0: index,
+func.func private @copy_scalar_into_1D_strided_dynamic_stride(%stride0: index,
   %stride1: index, %src : memref<1x1xf32>, %dst : memref<1x108xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [1, 1], strides: [%stride0, %stride1]
     : memref<1x108xf32>
       to memref<1x1xf32, strided<[?, ?]>>
@@ -93,36 +95,37 @@ func.func private @copy_to_strided_dynamic_stride(%stride0: index,
   // CHECK:      %[[C0:.*]] = arith.constant 0 : index
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]]] : memref<1x1xf32>
   // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]]] : memref<1x108xf32>
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<1x1xf32>
       to memref<1x1xf32, strided<[?, ?]>>
   // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @copy_to_strided_rank0(
+// CHECK-LABEL: func.func private @copy_0D_into_0D_strided(
 // CHECK-SAME:   %[[SRC:.*]]: memref<f32>, %[[DST:.*]]: memref<f32>
-func.func private @copy_to_strided_rank0(%src : memref<f32>, %dst : memref<f32>) {
+func.func private @copy_0D_into_0D_strided(%src : memref<f32>, %dst : memref<f32>) {
   // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [], strides: []
     : memref<f32> to memref<f32>
 
   // CHECK-NOT:  memref.copy
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][] : memref<f32>
   // CHECK:      memref.store %[[VAL]], %[[DST]][] : memref<f32>
-  memref.copy %src, %reinterpret_cast : memref<f32> to memref<f32>
+  memref.copy %src, %rc : memref<f32> to memref<f32>
   // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @copy_to_strided_0d_base_2d(
+/// Effectively a 2D array within a MemRef with rank >= 2
+// CHECK-LABEL: func.func private @copy_scalar_into_2D_strided(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x1x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
-func.func private @copy_to_strided_0d_base_2d(
+func.func private @copy_scalar_into_2D_strided(
   %src : memref<1x1x1xf32>, %dst : memref<1x33x42xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [1, 1, 1], strides: [1, 1, 1]
     : memref<1x33x42xf32>
       to memref<1x1x1xf32>
@@ -130,19 +133,19 @@ func.func private @copy_to_strided_0d_base_2d(
   // CHECK:      %[[C0:.*]] = arith.constant 0 : index
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]], %[[C0]]] : memref<1x1x1xf32>
   // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]], %[[C0]]] : memref<1x33x42xf32>
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<1x1x1xf32> to memref<1x1x1xf32>
   // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @copy_to_strided_1d_vector_zero_offset(
+// CHECK-LABEL: func.func private @copy_1D_into_1D_strided_zero_offset(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x3x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x3x11xf32>
-func.func private @copy_to_strided_1d_vector_zero_offset(
+func.func private @copy_1D_into_1D_strided_zero_offset(
   %src : memref<1x3x1xf32>, %dst : memref<1x3x11xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [1, 3, 1], strides: [33, 11, 1]
     : memref<1x3x11xf32>
       to memref<1x3x1xf32, strided<[33, 11, 1]>>
@@ -155,20 +158,20 @@ func.func private @copy_to_strided_1d_vector_zero_offset(
   // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x3x1xf32>
   // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x3x11xf32>
   // CHECK:      }
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<1x3x1xf32>
       to memref<1x3x1xf32, strided<[33, 11, 1]>>
   // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @copy_to_strided_1d_vector_nonzero_offset(
+// CHECK-LABEL: func.func private @copy_1D_into_2D_strided_nonzero_offset(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x3x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x3x11xf32>
-func.func private @copy_to_strided_1d_vector_nonzero_offset(
+func.func private @copy_1D_into_2D_strided_nonzero_offset(
   %src : memref<1x3x1xf32>, %dst : memref<1x3x11xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [10], sizes: [1, 3, 1], strides: [33, 11, 1]
     : memref<1x3x11xf32>
       to memref<1x3x1xf32, strided<[33, 11, 1], offset: 10>>
@@ -182,21 +185,21 @@ func.func private @copy_to_strided_1d_vector_nonzero_offset(
   // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x3x1xf32>
   // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[C10]]] : memref<1x3x11xf32>
   // CHECK:      }
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<1x3x1xf32>
       to memref<1x3x1xf32, strided<[33, 11, 1], offset: 10>>
   // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @copy_to_strided_1d_vector_1d_base_dynamic_offset(
+// CHECK-LABEL: func.func private @copy_1D_into_1D_strided_dynamic_offset(
 // CHECK-SAME:   %[[OFF:.*]]: index
 // CHECK-SAME:   %[[SRC:.*]]: memref<4xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<42xf32>
-func.func private @copy_to_strided_1d_vector_1d_base_dynamic_offset(
+func.func private @copy_1D_into_1D_strided_dynamic_offset(
   %offset : index, %src : memref<4xf32>, %dst : memref<42xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [%offset], sizes: [4], strides: [1]
     : memref<42xf32> to memref<4xf32, strided<[1], offset: ?>>
 
@@ -209,19 +212,19 @@ func.func private @copy_to_strided_1d_vector_1d_base_dynamic_offset(
   // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[IDX]]] : memref<4xf32>
   // CHECK:        memref.store %[[VAL]], %[[DST]][%[[DST_IDX]]] : memref<42xf32>
   // CHECK:      }
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<4xf32> to memref<4xf32, strided<[1], offset: ?>>
   // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @copy_to_strided_2d_vector_nonzero_offset(
+// CHECK-LABEL: func.func private @copy_2D_into_2D_strided_nonzero_offset(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x3x4xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x3x11xf32>
-func.func private @copy_to_strided_2d_vector_nonzero_offset(
+func.func private @copy_2D_into_2D_strided_nonzero_offset(
   %src : memref<1x3x4xf32>, %dst : memref<1x3x11xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [7], sizes: [1, 3, 4], strides: [33, 11, 1]
     : memref<1x3x11xf32>
       to memref<1x3x4xf32, strided<[33, 11, 1], offset: 7>>
@@ -239,7 +242,7 @@ func.func private @copy_to_strided_2d_vector_nonzero_offset(
   // CHECK:          memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX0]], %[[DST_IDX]]] : memref<1x3x11xf32>
   // CHECK:        }
   // CHECK:      }
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<1x3x4xf32>
       to memref<1x3x4xf32, strided<[33, 11, 1], offset: 7>>
   // CHECK-NOT:  memref.copy
@@ -250,11 +253,11 @@ func.func private @copy_to_strided_2d_vector_nonzero_offset(
 // Negative tests (must NOT rewrite)
 //===----------------------------------------------------------------------===//
 
-// CHECK-LABEL: func.func private @negative_copy_to_strided_non_identity_base(
-func.func private @negative_copy_to_strided_non_identity_base(%src: memref<1x1xf32>,
+// CHECK-LABEL: func.func private @negative_copy_into_strided_non_identity(
+func.func private @negative_copy_into_strided_non_identity(%src: memref<1x1xf32>,
   %dst: memref<8x1xf32, strided<[10, 2]>>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [6], sizes: [1, 1], strides: [11, 80]
     : memref<8x1xf32, strided<[10, 2]>>
       to memref<1x1xf32, strided<[11, 80], offset: 6>>
@@ -262,153 +265,195 @@ func.func private @negative_copy_to_strided_non_identity_base(%src: memref<1x1xf
   // CHECK:      memref.copy %arg0, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<1x1xf32> to memref<1x1xf32, strided<[11, 80], offset: 6>>
 
   return
 }
 
-// CHECK-LABEL: func.func private @negative_copy_to_strided_overlapping_result_dims(
-func.func private @negative_copy_to_strided_overlapping_result_dims(%src : memref<3x3xf32>,
+// CHECK-LABEL: func.func private @negative_copy_into_strided_overlapping_result_dims(
+func.func private @negative_copy_into_strided_overlapping_result_dims(%src : memref<3x3xf32>,
   %dst : memref<4x4xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [3, 3], strides: [1, 1]
     : memref<4x4xf32> to memref<3x3xf32, strided<[1, 1]>>
 
   // CHECK:      memref.copy %arg0, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<3x3xf32> to memref<3x3xf32, strided<[1, 1]>>
   return
 }
 
-// CHECK-LABEL: func.func private @negative_copy_to_strided_rank_change(
-func.func private @negative_copy_to_strided_rank_change(%src : memref<2x3xf32>,
+// CHECK-LABEL: func.func private @negative_copy_1D_into_2D_strided_unmatched_strides(
+func.func private @negative_copy_1D_into_2D_strided_unmatched_strides(
+  %src : memref<1x3x1xf32>, %dst : memref<1x4x8xf32>) {
+  // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
+  %rc = memref.reinterpret_cast %dst
+    to offset: [0], sizes: [1, 3, 1], strides: [32, 5, 1]
+    : memref<1x4x8xf32>
+      to memref<1x3x1xf32, strided<[32, 5, 1]>>
+
+  // CHECK:      memref.copy %arg0, %reinterpret_cast
+  // CHECK-NOT:  memref.load
+  // CHECK-NOT:  memref.store
+  memref.copy %src, %rc
+    : memref<1x3x1xf32>
+      to memref<1x3x1xf32, strided<[32, 5, 1]>>
+  return
+}
+
+// CHECK-LABEL: func.func private @negative_copy_2D_into_2D_strided_unmatched_strides(
+func.func private @negative_copy_2D_into_2D_strided_unmatched_strides(
+  %src : memref<1x3x4xf32>, %dst : memref<1x4x3xf32>) {
+  // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
+  %rc = memref.reinterpret_cast %dst
+    to offset: [0], sizes: [1, 3, 4], strides: [12, 4, 1]
+    : memref<1x4x3xf32>
+      to memref<1x3x4xf32, strided<[12, 4, 1]>>
+
+  // CHECK:      memref.copy %arg0, %reinterpret_cast
+  // CHECK-NOT:  memref.load
+  // CHECK-NOT:  memref.store
+  memref.copy %src, %rc
+    : memref<1x3x4xf32>
+      to memref<1x3x4xf32, strided<[12, 4, 1]>>
+  return
+}
+
+/// The linear accessed region is in-bounds, but result dim 1 has size 5 while
+/// the matching source dim has size 4. Directly using the loop IV as the source
+/// dim index would be out-of-bounds. Each loop IV value would need to be
+/// linearized with the result stride and then delinearized into source indices.
+// CHECK-LABEL: func.func private @negative_copy_into_strided_crosses_source_dim_boundary(
+func.func private @negative_copy_into_strided_crosses_source_dim_boundary(
+  %src : memref<1x5xf32>, %dst : memref<2x4xf32>) {
+  // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
+  %rc = memref.reinterpret_cast %dst
+    to offset: [0], sizes: [1, 5], strides: [4, 1]
+    : memref<2x4xf32>
+      to memref<1x5xf32, strided<[4, 1]>>
+
+  // CHECK:      memref.copy %arg0, %reinterpret_cast
+  // CHECK-NOT:  memref.load
+  // CHECK-NOT:  memref.store
+  memref.copy %src, %rc
+    : memref<1x5xf32>
+      to memref<1x5xf32, strided<[4, 1]>>
+  return
+}
+
+// CHECK-LABEL: func.func private @negative_copy_into_strided_rank_change(
+func.func private @negative_copy_into_strided_rank_change(%src : memref<2x3xf32>,
   %dst : memref<6xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [2, 3], strides: [3, 1]
     : memref<6xf32> to memref<2x3xf32>
 
   // CHECK:      memref.copy %arg0, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<2x3xf32> to memref<2x3xf32>
   return
 }
 
-// CHECK-LABEL: func.func private @negative_copy_to_strided_dynamic_copy_source_shape(
-func.func private @negative_copy_to_strided_dynamic_copy_source_shape(%src : memref<?xf32>,
+// CHECK-LABEL: func.func private @negative_copy_into_strided_dynamic_copy_source_shape(
+func.func private @negative_copy_into_strided_dynamic_copy_source_shape(%src : memref<?xf32>,
   %dst : memref<4xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [4], strides: [1]
     : memref<4xf32> to memref<4xf32>
 
   // CHECK:      memref.copy %arg0, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<?xf32> to memref<4xf32>
   return
 }
 
-// CHECK-LABEL: func.func private @negative_copy_to_strided_dynamic_rc_shapes(
-func.func private @negative_copy_to_strided_dynamic_rc_shapes(%dim : index,
+// CHECK-LABEL: func.func private @negative_copy_into_strided_dynamic_rc_shapes(
+func.func private @negative_copy_into_strided_dynamic_rc_shapes(%dim : index,
   %src : memref<4xf32>, %dst : memref<?xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [%dim], strides: [1]
     : memref<?xf32> to memref<?xf32, strided<[1]>>
 
   // CHECK:      memref.copy %arg1, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<4xf32> to memref<?xf32, strided<[1]>>
   return
 }
 
-// CHECK-LABEL: func.func private @negative_copy_to_strided_unranked_rc_base(
-func.func private @negative_copy_to_strided_unranked_rc_base(
+// CHECK-LABEL: func.func private @negative_copy_into_strided_unranked_rc_base(
+func.func private @negative_copy_into_strided_unranked_rc_base(
   %src : memref<4xf32>, %dst : memref<*xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [4], strides: [1]
     : memref<*xf32> to memref<4xf32>
 
   // CHECK:      memref.copy %arg0, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<4xf32> to memref<4xf32>
   return
 }
 
-// CHECK-LABEL: func.func private @negative_copy_to_strided_0d_base_2d_dynamic_offset(
-func.func private @negative_copy_to_strided_0d_base_2d_dynamic_offset(
+// CHECK-LABEL: func.func private @negative_copy_into_multidim_strided_dynamic_offset(
+func.func private @negative_copy_into_multidim_strided_dynamic_offset(
   %offset : index, %src : memref<1x1xf32>, %dst : memref<4x8xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [%offset], sizes: [1, 1], strides: [8, 1]
     : memref<4x8xf32> to memref<1x1xf32, strided<[8, 1], offset: ?>>
 
   // CHECK:      memref.copy %arg1, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<1x1xf32>
       to memref<1x1xf32, strided<[8, 1], offset: ?>>
   return
 }
 
-// CHECK-LABEL: func.func private @negative_copy_to_strided_1d_base_2d_dynamic_offset(
-func.func private @negative_copy_to_strided_1d_base_2d_dynamic_offset(
-  %offset : index, %src : memref<1x3x1xf32>,
-  %dst : memref<1x3x11xf32>) {
-  // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
-  %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [%offset], sizes: [1, 3, 1], strides: [33, 11, 1]
-    : memref<1x3x11xf32>
-      to memref<1x3x1xf32, strided<[33, 11, 1], offset: ?>>
-
-  // CHECK:      memref.copy %arg1, %reinterpret_cast
-  // CHECK-NOT:  memref.load
-  // CHECK-NOT:  memref.store
-  memref.copy %src, %reinterpret_cast
-    : memref<1x3x1xf32>
-      to memref<1x3x1xf32, strided<[33, 11, 1], offset: ?>>
-  return
-}
-
-// CHECK-LABEL: func.func private @negative_copy_to_strided_2d_dynamic_offset(
-func.func private @negative_copy_to_strided_2d_dynamic_offset(
+/// For effectively-1D copies with dynamic offsets, the single non-unit result
+/// dimension must map to the single non-unit source dimension. Otherwise the
+/// dynamic linear offset would need runtime delinearization before adding IVs.
+// CHECK-LABEL: func.func private @negative_copy_multidim_into_1D_strided_dynamic_offset(
+func.func private @negative_copy_multidim_into_1D_strided_dynamic_offset(
   %offset : index, %src : memref<1x3x4xf32>,
-  %dst : memref<1x3x11xf32>) {
+  %dst : memref<1x12x1xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
-  %reinterpret_cast = memref.reinterpret_cast %dst
-    to offset: [%offset], sizes: [1, 3, 4], strides: [33, 11, 1]
-    : memref<1x3x11xf32>
-      to memref<1x3x4xf32, strided<[33, 11, 1], offset: ?>>
+  %rc = memref.reinterpret_cast %dst
+    to offset: [%offset], sizes: [1, 3, 4], strides: [12, 4, 1]
+    : memref<1x12x1xf32>
+      to memref<1x3x4xf32, strided<[12, 4, 1], offset: ?>>
 
   // CHECK:      memref.copy %arg1, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<1x3x4xf32>
-      to memref<1x3x4xf32, strided<[33, 11, 1], offset: ?>>
+      to memref<1x3x4xf32, strided<[12, 4, 1], offset: ?>>
   return
 }
 
 /// Non-unit copied dimension needs stride-based address computation.
-// CHECK-LABEL: func.func private @negative_copy_to_strided_dynamic_rc_stride(
-func.func private @negative_copy_to_strided_dynamic_rc_stride(%stride : index,
+// CHECK-LABEL: func.func private @negative_copy_into_strided_dynamic_rc_stride(
+func.func private @negative_copy_into_strided_dynamic_rc_stride(%stride : index,
   %src : memref<1x3x1xf32>, %dst : memref<1x3x11xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
-  %reinterpret_cast = memref.reinterpret_cast %dst
+  %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [1, 3, 1], strides: [33, %stride, 1]
     : memref<1x3x11xf32>
       to memref<1x3x1xf32, strided<[33, ?, 1]>>
@@ -416,7 +461,7 @@ func.func private @negative_copy_to_strided_dynamic_rc_stride(%stride : index,
   // CHECK:      memref.copy %arg1, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
-  memref.copy %src, %reinterpret_cast
+  memref.copy %src, %rc
     : memref<1x3x1xf32>
       to memref<1x3x1xf32, strided<[33, ?, 1]>>
   return

>From ae4bd445afa3c6a31d7ed3468d05240209c5eed8 Mon Sep 17 00:00:00 2001
From: Ioana Ghiban <ioana.ghiban at arm.com>
Date: Mon, 29 Jun 2026 15:04:44 +0200
Subject: [PATCH 8/8] Address fourth round of comments

---
 .../Transforms/ElideReinterpretCast.cpp       |  23 +-
 .../MemRef/elide-reinterpret-cast.mlir        | 270 +++++++++++-------
 2 files changed, 181 insertions(+), 112 deletions(-)

diff --git a/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp b/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
index 435600f58f7fa..6cd56eefb9562 100644
--- a/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
+++ b/mlir/lib/Dialect/MemRef/Transforms/ElideReinterpretCast.cpp
@@ -51,8 +51,8 @@ struct AssocMapAndOffsetsForRC {
   std::optional<SmallVector<int64_t>> delinearizedOffsets;
 };
 
-/// Records the reinterpret_cast result dimensions that span more than one
-/// element and maps each one to its corresponding source dimension.
+/// Maps each non-unit result dimension to a source dimension. Returns false if
+/// a stride is dynamic or no distinct source dimension matches.
 static bool findSourceDimForResultDim(memref::ReinterpretCastOp rc,
                                       AssocMapAndOffsetsForRC &mapAndOffs) {
   MemRefType resType = dyn_cast<MemRefType>(rc.getType());
@@ -62,8 +62,9 @@ static bool findSourceDimForResultDim(memref::ReinterpretCastOp rc,
 
   SmallVector<int64_t> srcIdentityStrides = computeStrides(srcType.getShape());
 
-  // Reusing a source dimension would require delinearizing the combined linear
-  // offset, which is TODO.
+  // Each non-unit result dimension needs one source dimension to receive its
+  // loop IV. Combining multiple IVs into one source index would require
+  // linearizing the result position which is TODO.
   SmallVector<bool> usedSrcDims(srcType.getRank(), false);
 
   for (auto [resultDim, resultSize] : llvm::enumerate(resType.getShape())) {
@@ -76,14 +77,16 @@ static bool findSourceDimForResultDim(memref::ReinterpretCastOp rc,
 
     int64_t resultStride = rc.getStaticStrides()[resultDim];
     std::optional<unsigned> srcDim;
-    // Find an unused source dimension with matching stride and enough elements.
+    // Pick the first unused source dimension with the same stride.
     for (auto [idx, stride] : llvm::enumerate(srcIdentityStrides)) {
-      if (usedSrcDims[idx] || stride != resultStride ||
-          srcType.getDimSize(idx) < resultSize)
+      if (usedSrcDims[idx] || stride != resultStride)
         continue;
 
-      if (!srcDim || srcType.getDimSize(idx) < srcType.getDimSize(*srcDim))
-        srcDim = idx;
+      assert(srcType.getDimSize(idx) >= resultSize &&
+             "reinterpret_cast result dimension does not fit in the matching "
+             "source dimension");
+      srcDim = idx;
+      break;
     }
     if (!srcDim)
       return false;
@@ -120,7 +123,7 @@ delinearizeStaticRCOffset(memref::ReinterpretCastOp rc) {
   SmallVector<int64_t> offsetIdxs(srcType.getRank(), 0);
   int64_t remainder = rcOffsets[0];
   SmallVector<int64_t> srcStrides = computeStrides(srcType.getShape());
-  // Convert the linear reinterpret_cast offset to per-dimension source starting
+  // Convert the scalar reinterpret_cast offset to per-dimension source starting
   // indices.
   for (auto [dim, stride] : llvm::enumerate(srcStrides)) {
     offsetIdxs[dim] = remainder / stride;
diff --git a/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir b/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
index eaa823e4afd3d..d622705a18025 100644
--- a/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
+++ b/mlir/test/Dialect/MemRef/elide-reinterpret-cast.mlir
@@ -3,10 +3,10 @@
 
 //===----------------------------------------------------------------------===//
 // Positive tests
+//
+// The destination is effectively a 1D array within a MemRef with rank >= 1 
 //===----------------------------------------------------------------------===//
 
-/// Effectively copied scalar within a MemRef with rank >= 0
-/// to practically a 1D array within a MemRef with rank >= 1
 // CHECK-LABEL: func.func private @copy_scalar_into_1D_strided_zero_offset(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x108xf32>
@@ -42,9 +42,9 @@ func.func private @copy_scalar_into_1D_strided_nonzero_offset(%src : memref<1x1x
 
   // CHECK-NOT:  memref.copy
   // CHECK:      %[[C0:.*]] = arith.constant 0 : index
-  // CHECK:      %[[C1:.*]] = arith.constant 1 : index
+  // CHECK:      %[[OFF:.*]] = arith.constant 1 : index
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]]] : memref<1x1xf32>
-  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C1]]] : memref<1x108xf32>
+  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[OFF]]] : memref<1x108xf32>
   memref.copy %src, %rc
     : memref<1x1xf32>
       to memref<1x1xf32, strided<[1, 1], offset: 1>>
@@ -77,7 +77,26 @@ func.func private @copy_scalar_into_1D_strided_dynamic_offset(%offset: index, %s
   return
 }
 
-// Dynamic strides are irrelevant because all strided memref indices are zero.
+// Strides are irrelevant because all strided memref indices are zero.
+// CHECK-LABEL: func.func private @copy_scalar_into_1D_strided_static_stride(
+// CHECK-SAME:   %[[SRC:.*]]: memref<1x1xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x108xf32>
+func.func private @copy_scalar_into_1D_strided_static_stride(%src : memref<1x1xf32>,
+  %dst : memref<1x108xf32>) {
+  // CHECK-NOT:  memref.reinterpret_cast
+  %reinterpret_cast = memref.reinterpret_cast %dst
+    to offset: [0], sizes: [1, 1], strides: [107, 2]
+    : memref<1x108xf32> to memref<1x1xf32, strided<[107, 2]>>
+
+  // CHECK-NOT:  memref.copy
+  // CHECK:      %[[C0:.*]] = arith.constant 0 : index
+  // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]]] : memref<1x1xf32>
+  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]]] : memref<1x108xf32>
+  memref.copy %src, %reinterpret_cast
+    : memref<1x1xf32> to memref<1x1xf32, strided<[107, 2]>>
+  return
+}
+
 // CHECK-LABEL: func.func private @copy_scalar_into_1D_strided_dynamic_stride(
 // CHECK-SAME:   %[[STR0:[A-Za-z][A-Za-z0-9-]*]]: index
 // CHECK-SAME:   %[[STR1:[A-Za-z][A-Za-z0-9-]*]]: index
@@ -102,9 +121,41 @@ func.func private @copy_scalar_into_1D_strided_dynamic_stride(%stride0: index,
   return
 }
 
-// CHECK-LABEL: func.func private @copy_0D_into_0D_strided(
+// CHECK-LABEL: func.func private @copy_1D_into_1D_strided_dynamic_offset(
+// CHECK-SAME:   %[[OFF:.*]]: index
+// CHECK-SAME:   %[[SRC:.*]]: memref<4xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<108xf32>
+func.func private @copy_1D_into_1D_strided_dynamic_offset(
+  %offset : index, %src : memref<4xf32>, %dst : memref<108xf32>) {
+  // CHECK-NOT:  memref.reinterpret_cast
+  %rc = memref.reinterpret_cast %dst
+    to offset: [%offset], sizes: [4], strides: [1]
+    : memref<108xf32> to memref<4xf32, strided<[1], offset: ?>>
+
+  // CHECK-NOT:  memref.copy
+  // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
+  // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
+  // CHECK-DAG:  %[[UB:.*]] = arith.constant 4 : index
+  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[UB]] step %[[C1]] {
+  // CHECK:        %[[DST_IDX:.*]] = arith.addi %[[OFF]], %[[IDX]] : index
+  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[IDX]]] : memref<4xf32>
+  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[DST_IDX]]] : memref<108xf32>
+  // CHECK:      }
+  memref.copy %src, %rc
+    : memref<4xf32> to memref<4xf32, strided<[1], offset: ?>>
+  // CHECK-NOT:  memref.copy
+  return
+}
+
+//===----------------------------------------------------------------------===//
+// Positive tests
+//
+// The destination is effectively a scalar within a MemRef with rank == 0 
+//===----------------------------------------------------------------------===//
+
+// CHECK-LABEL: func.func private @copy_scalar_into_0D_strided_zero_offset(
 // CHECK-SAME:   %[[SRC:.*]]: memref<f32>, %[[DST:.*]]: memref<f32>
-func.func private @copy_0D_into_0D_strided(%src : memref<f32>, %dst : memref<f32>) {
+func.func private @copy_scalar_into_0D_strided_zero_offset(%src : memref<f32>, %dst : memref<f32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [], strides: []
@@ -118,31 +169,36 @@ func.func private @copy_0D_into_0D_strided(%src : memref<f32>, %dst : memref<f32
   return
 }
 
-/// Effectively a 2D array within a MemRef with rank >= 2
+//===----------------------------------------------------------------------===//
+// Positive tests
+//
+// The destination is effectively a 2D array within a MemRef with rank >= 2 
+//===----------------------------------------------------------------------===//
+
 // CHECK-LABEL: func.func private @copy_scalar_into_2D_strided(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x1x1xf32>
-// CHECK-SAME:   %[[DST:.*]]: memref<1x33x42xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x3x11xf32>
 func.func private @copy_scalar_into_2D_strided(
-  %src : memref<1x1x1xf32>, %dst : memref<1x33x42xf32>) {
+  %src : memref<1x1x1xf32>, %dst : memref<1x3x11xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [1, 1, 1], strides: [1, 1, 1]
-    : memref<1x33x42xf32>
+    : memref<1x3x11xf32>
       to memref<1x1x1xf32>
   // CHECK-NOT:  memref.copy
   // CHECK:      %[[C0:.*]] = arith.constant 0 : index
   // CHECK:      %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[C0]], %[[C0]]] : memref<1x1x1xf32>
-  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]], %[[C0]]] : memref<1x33x42xf32>
+  // CHECK:      memref.store %[[VAL]], %[[DST]][%[[C0]], %[[C0]], %[[C0]]] : memref<1x3x11xf32>
   memref.copy %src, %rc
     : memref<1x1x1xf32> to memref<1x1x1xf32>
   // CHECK-NOT:  memref.copy
   return
 }
 
-// CHECK-LABEL: func.func private @copy_1D_into_1D_strided_zero_offset(
+// CHECK-LABEL: func.func private @copy_1D_into_2D_strided_zero_offset(
 // CHECK-SAME:   %[[SRC:.*]]: memref<1x3x1xf32>
 // CHECK-SAME:   %[[DST:.*]]: memref<1x3x11xf32>
-func.func private @copy_1D_into_1D_strided_zero_offset(
+func.func private @copy_1D_into_2D_strided_zero_offset(
   %src : memref<1x3x1xf32>, %dst : memref<1x3x11xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %rc = memref.reinterpret_cast %dst
@@ -153,8 +209,8 @@ func.func private @copy_1D_into_1D_strided_zero_offset(
   // CHECK-NOT:  memref.copy
   // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
   // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
-  // CHECK-DAG:  %[[C3:.*]] = arith.constant 3 : index
-  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C3]] step %[[C1]] {
+  // CHECK-DAG:  %[[UB:.*]] = arith.constant 3 : index
+  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[UB]] step %[[C1]] {
   // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x3x1xf32>
   // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x3x11xf32>
   // CHECK:      }
@@ -179,11 +235,11 @@ func.func private @copy_1D_into_2D_strided_nonzero_offset(
   // CHECK-NOT:  memref.copy
   // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
   // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
-  // CHECK-DAG:  %[[C3:.*]] = arith.constant 3 : index
-  // CHECK-DAG:  %[[C10:.*]] = arith.constant 10 : index
-  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C3]] step %[[C1]] {
+  // CHECK-DAG:  %[[UB:.*]] = arith.constant 3 : index
+  // CHECK-DAG:  %[[OFF:.*]] = arith.constant 10 : index
+  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[UB]] step %[[C1]] {
   // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX]], %[[C0]]] : memref<1x3x1xf32>
-  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[C10]]] : memref<1x3x11xf32>
+  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX]], %[[OFF]]] : memref<1x3x11xf32>
   // CHECK:      }
   memref.copy %src, %rc
     : memref<1x3x1xf32>
@@ -192,28 +248,31 @@ func.func private @copy_1D_into_2D_strided_nonzero_offset(
   return
 }
 
-// CHECK-LABEL: func.func private @copy_1D_into_1D_strided_dynamic_offset(
-// CHECK-SAME:   %[[OFF:.*]]: index
-// CHECK-SAME:   %[[SRC:.*]]: memref<4xf32>
-// CHECK-SAME:   %[[DST:.*]]: memref<42xf32>
-func.func private @copy_1D_into_1D_strided_dynamic_offset(
-  %offset : index, %src : memref<4xf32>, %dst : memref<42xf32>) {
+// CHECK-LABEL: func.func private @copy_2D_into_2D_strided_zero_offset(
+// CHECK-SAME:   %[[SRC:.*]]: memref<1x3x4xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x3x11xf32>
+func.func private @copy_2D_into_2D_strided_zero_offset(
+  %src : memref<1x3x4xf32>, %dst : memref<1x3x11xf32>) {
   // CHECK-NOT:  memref.reinterpret_cast
   %rc = memref.reinterpret_cast %dst
-    to offset: [%offset], sizes: [4], strides: [1]
-    : memref<42xf32> to memref<4xf32, strided<[1], offset: ?>>
+    to offset: [0], sizes: [1, 3, 4], strides: [33, 11, 1]
+    : memref<1x3x11xf32>
+      to memref<1x3x4xf32, strided<[33, 11, 1]>>
 
   // CHECK-NOT:  memref.copy
   // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
   // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
-  // CHECK-DAG:  %[[C4:.*]] = arith.constant 4 : index
-  // CHECK:      scf.for %[[IDX:.*]] = %[[C0]] to %[[C4]] step %[[C1]] {
-  // CHECK:        %[[DST_IDX:.*]] = arith.addi %[[OFF]], %[[IDX]] : index
-  // CHECK:        %[[VAL:.*]] = memref.load %[[SRC]][%[[IDX]]] : memref<4xf32>
-  // CHECK:        memref.store %[[VAL]], %[[DST]][%[[DST_IDX]]] : memref<42xf32>
+  // CHECK-DAG:  %[[UB0:.*]] = arith.constant 3 : index
+  // CHECK-DAG:  %[[UB1:.*]] = arith.constant 4 : index
+  // CHECK:      scf.for %[[IDX0:.*]] = %[[C0]] to %[[UB0]] step %[[C1]] {
+  // CHECK:        scf.for %[[IDX1:.*]] = %[[C0]] to %[[UB1]] step %[[C1]] {
+  // CHECK:          %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX0]], %[[IDX1]]] : memref<1x3x4xf32>
+  // CHECK:          memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX0]], %[[IDX1]]] : memref<1x3x11xf32>
+  // CHECK:        }
   // CHECK:      }
   memref.copy %src, %rc
-    : memref<4xf32> to memref<4xf32, strided<[1], offset: ?>>
+    : memref<1x3x4xf32>
+      to memref<1x3x4xf32, strided<[33, 11, 1]>>
   // CHECK-NOT:  memref.copy
   return
 }
@@ -232,12 +291,12 @@ func.func private @copy_2D_into_2D_strided_nonzero_offset(
   // CHECK-NOT:  memref.copy
   // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
   // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
-  // CHECK-DAG:  %[[C3:.*]] = arith.constant 3 : index
-  // CHECK-DAG:  %[[C4:.*]] = arith.constant 4 : index
-  // CHECK-DAG:  %[[C7:.*]] = arith.constant 7 : index
-  // CHECK:      scf.for %[[IDX0:.*]] = %[[C0]] to %[[C3]] step %[[C1]] {
-  // CHECK:        scf.for %[[IDX1:.*]] = %[[C0]] to %[[C4]] step %[[C1]] {
-  // CHECK:          %[[DST_IDX:.*]] = arith.addi %[[C7]], %[[IDX1]] : index
+  // CHECK-DAG:  %[[UB0:.*]] = arith.constant 3 : index
+  // CHECK-DAG:  %[[UB1:.*]] = arith.constant 4 : index
+  // CHECK-DAG:  %[[OFF:.*]] = arith.constant 7 : index
+  // CHECK:      scf.for %[[IDX0:.*]] = %[[C0]] to %[[UB0]] step %[[C1]] {
+  // CHECK:        scf.for %[[IDX1:.*]] = %[[C0]] to %[[UB1]] step %[[C1]] {
+  // CHECK:          %[[DST_IDX:.*]] = arith.addi %[[OFF]], %[[IDX1]] : index
   // CHECK:          %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX0]], %[[IDX1]]] : memref<1x3x4xf32>
   // CHECK:          memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX0]], %[[DST_IDX]]] : memref<1x3x11xf32>
   // CHECK:        }
@@ -249,59 +308,72 @@ func.func private @copy_2D_into_2D_strided_nonzero_offset(
   return
 }
 
+// CHECK-LABEL: func.func private @copy_2D_into_2D_strided_rc_non_identity_strides(
+// CHECK-SAME:   %[[SRC:.*]]: memref<1x4x3xf32>
+// CHECK-SAME:   %[[DST:.*]]: memref<1x3x4xf32>
+func.func private @copy_2D_into_2D_strided_rc_non_identity_strides(
+  %src : memref<1x4x3xf32>, %dst : memref<1x3x4xf32>) {
+  // CHECK-NOT:  memref.reinterpret_cast
+  %rc = memref.reinterpret_cast %dst
+    to offset: [0], sizes: [1, 4, 3], strides: [12, 1, 4]
+    : memref<1x3x4xf32>
+      to memref<1x4x3xf32, strided<[12, 1, 4]>>
+
+  // CHECK-NOT:  memref.copy
+  // CHECK-DAG:  %[[C0:.*]] = arith.constant 0 : index
+  // CHECK-DAG:  %[[C1:.*]] = arith.constant 1 : index
+  // CHECK-DAG:  %[[UB0:.*]] = arith.constant 3 : index
+  // CHECK-DAG:  %[[UB1:.*]] = arith.constant 4 : index
+  // CHECK:      scf.for %[[IDX0:.*]] = %[[C0]] to %[[UB1]] step %[[C1]] {
+  // CHECK:        scf.for %[[IDX1:.*]] = %[[C0]] to %[[UB0]] step %[[C1]] {
+  // CHECK:          %[[VAL:.*]] = memref.load %[[SRC]][%[[C0]], %[[IDX0]], %[[IDX1]]] : memref<1x4x3xf32>
+  // CHECK:          memref.store %[[VAL]], %[[DST]][%[[C0]], %[[IDX1]], %[[IDX0]]] : memref<1x3x4xf32>
+  // CHECK:        }
+  // CHECK:      }
+  memref.copy %src, %rc
+    : memref<1x4x3xf32>
+      to memref<1x4x3xf32, strided<[12, 1, 4]>>
+  // CHECK-NOT:  memref.copy
+  return
+}
+
 //===----------------------------------------------------------------------===//
 // Negative tests (must NOT rewrite)
 //===----------------------------------------------------------------------===//
 
 // CHECK-LABEL: func.func private @negative_copy_into_strided_non_identity(
 func.func private @negative_copy_into_strided_non_identity(%src: memref<1x1xf32>,
-  %dst: memref<8x1xf32, strided<[10, 2]>>) {
+  %dst: memref<108x1xf32, strided<[10, 2]>>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
   %rc = memref.reinterpret_cast %dst
-    to offset: [6], sizes: [1, 1], strides: [11, 80]
-    : memref<8x1xf32, strided<[10, 2]>>
-      to memref<1x1xf32, strided<[11, 80], offset: 6>>
+    to offset: [6], sizes: [1, 1], strides: [10, 2]
+    : memref<108x1xf32, strided<[10, 2]>>
+      to memref<1x1xf32, strided<[10, 2], offset: 6>>
 
   // CHECK:      memref.copy %arg0, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
   memref.copy %src, %rc
-    : memref<1x1xf32> to memref<1x1xf32, strided<[11, 80], offset: 6>>
+    : memref<1x1xf32> to memref<1x1xf32, strided<[10, 2], offset: 6>>
 
   return
 }
 
-// CHECK-LABEL: func.func private @negative_copy_into_strided_overlapping_result_dims(
-func.func private @negative_copy_into_strided_overlapping_result_dims(%src : memref<3x3xf32>,
-  %dst : memref<4x4xf32>) {
-  // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
-  %rc = memref.reinterpret_cast %dst
-    to offset: [0], sizes: [3, 3], strides: [1, 1]
-    : memref<4x4xf32> to memref<3x3xf32, strided<[1, 1]>>
-
-  // CHECK:      memref.copy %arg0, %reinterpret_cast
-  // CHECK-NOT:  memref.load
-  // CHECK-NOT:  memref.store
-  memref.copy %src, %rc
-    : memref<3x3xf32> to memref<3x3xf32, strided<[1, 1]>>
-  return
-}
-
 // CHECK-LABEL: func.func private @negative_copy_1D_into_2D_strided_unmatched_strides(
 func.func private @negative_copy_1D_into_2D_strided_unmatched_strides(
-  %src : memref<1x3x1xf32>, %dst : memref<1x4x8xf32>) {
+  %src : memref<1x3x1xf32>, %dst : memref<1x3x11xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
   %rc = memref.reinterpret_cast %dst
-    to offset: [0], sizes: [1, 3, 1], strides: [32, 5, 1]
-    : memref<1x4x8xf32>
-      to memref<1x3x1xf32, strided<[32, 5, 1]>>
+    to offset: [0], sizes: [1, 3, 1], strides: [33, 10, 1]
+    : memref<1x3x11xf32>
+      to memref<1x3x1xf32, strided<[33, 10, 1]>>
 
   // CHECK:      memref.copy %arg0, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
   memref.copy %src, %rc
     : memref<1x3x1xf32>
-      to memref<1x3x1xf32, strided<[32, 5, 1]>>
+      to memref<1x3x1xf32, strided<[33, 10, 1]>>
   return
 }
 
@@ -323,67 +395,61 @@ func.func private @negative_copy_2D_into_2D_strided_unmatched_strides(
   return
 }
 
-/// The linear accessed region is in-bounds, but result dim 1 has size 5 while
-/// the matching source dim has size 4. Directly using the loop IV as the source
-/// dim index would be out-of-bounds. Each loop IV value would need to be
-/// linearized with the result stride and then delinearized into source indices.
-// CHECK-LABEL: func.func private @negative_copy_into_strided_crosses_source_dim_boundary(
-func.func private @negative_copy_into_strided_crosses_source_dim_boundary(
-  %src : memref<1x5xf32>, %dst : memref<2x4xf32>) {
+// CHECK-LABEL: func.func private @negative_copy_into_strided_rank_change(
+func.func private @negative_copy_into_strided_rank_change(%src : memref<3x4xf32>,
+  %dst : memref<12xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
   %rc = memref.reinterpret_cast %dst
-    to offset: [0], sizes: [1, 5], strides: [4, 1]
-    : memref<2x4xf32>
-      to memref<1x5xf32, strided<[4, 1]>>
+    to offset: [0], sizes: [3, 4], strides: [1, 1]
+    : memref<12xf32> to memref<3x4xf32, strided<[1, 1]>>
 
   // CHECK:      memref.copy %arg0, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
   memref.copy %src, %rc
-    : memref<1x5xf32>
-      to memref<1x5xf32, strided<[4, 1]>>
+    : memref<3x4xf32> to memref<3x4xf32, strided<[1, 1]>>
   return
 }
 
-// CHECK-LABEL: func.func private @negative_copy_into_strided_rank_change(
-func.func private @negative_copy_into_strided_rank_change(%src : memref<2x3xf32>,
-  %dst : memref<6xf32>) {
+// CHECK-LABEL: func.func private @negative_copy_into_strided_dynamic_copy_source_shape(
+func.func private @negative_copy_into_strided_dynamic_copy_source_shape(%src : memref<?xf32>,
+  %dst : memref<4xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
   %rc = memref.reinterpret_cast %dst
-    to offset: [0], sizes: [2, 3], strides: [3, 1]
-    : memref<6xf32> to memref<2x3xf32>
+    to offset: [0], sizes: [4], strides: [1]
+    : memref<4xf32> to memref<4xf32>
 
   // CHECK:      memref.copy %arg0, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
   memref.copy %src, %rc
-    : memref<2x3xf32> to memref<2x3xf32>
+    : memref<?xf32> to memref<4xf32>
   return
 }
 
-// CHECK-LABEL: func.func private @negative_copy_into_strided_dynamic_copy_source_shape(
-func.func private @negative_copy_into_strided_dynamic_copy_source_shape(%src : memref<?xf32>,
-  %dst : memref<4xf32>) {
+// CHECK-LABEL: func.func private @negative_copy_into_strided_dynamic_rc_source_shape(
+func.func private @negative_copy_into_strided_dynamic_rc_source_shape(
+  %src : memref<4xf32>, %dst : memref<?xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg1
   %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [4], strides: [1]
-    : memref<4xf32> to memref<4xf32>
+    : memref<?xf32> to memref<4xf32, strided<[1]>>
 
   // CHECK:      memref.copy %arg0, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
   memref.copy %src, %rc
-    : memref<?xf32> to memref<4xf32>
+    : memref<4xf32> to memref<4xf32, strided<[1]>>
   return
 }
 
-// CHECK-LABEL: func.func private @negative_copy_into_strided_dynamic_rc_shapes(
-func.func private @negative_copy_into_strided_dynamic_rc_shapes(%dim : index,
-  %src : memref<4xf32>, %dst : memref<?xf32>) {
+// CHECK-LABEL: func.func private @negative_copy_into_strided_dynamic_rc_result_shape(
+func.func private @negative_copy_into_strided_dynamic_rc_result_shape(%dim : index,
+  %src : memref<4xf32>, %dst : memref<12xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
   %rc = memref.reinterpret_cast %dst
     to offset: [0], sizes: [%dim], strides: [1]
-    : memref<?xf32> to memref<?xf32, strided<[1]>>
+    : memref<12xf32> to memref<?xf32, strided<[1]>>
 
   // CHECK:      memref.copy %arg1, %reinterpret_cast
   // CHECK-NOT:  memref.load
@@ -411,18 +477,18 @@ func.func private @negative_copy_into_strided_unranked_rc_base(
 
 // CHECK-LABEL: func.func private @negative_copy_into_multidim_strided_dynamic_offset(
 func.func private @negative_copy_into_multidim_strided_dynamic_offset(
-  %offset : index, %src : memref<1x1xf32>, %dst : memref<4x8xf32>) {
+  %offset : index, %src : memref<1x1xf32>, %dst : memref<3x4xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
   %rc = memref.reinterpret_cast %dst
-    to offset: [%offset], sizes: [1, 1], strides: [8, 1]
-    : memref<4x8xf32> to memref<1x1xf32, strided<[8, 1], offset: ?>>
+    to offset: [%offset], sizes: [1, 1], strides: [12, 1]
+    : memref<3x4xf32> to memref<1x1xf32, strided<[12, 1], offset: ?>>
 
   // CHECK:      memref.copy %arg1, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
   memref.copy %src, %rc
     : memref<1x1xf32>
-      to memref<1x1xf32, strided<[8, 1], offset: ?>>
+      to memref<1x1xf32, strided<[12, 1], offset: ?>>
   return
 }
 
@@ -451,19 +517,19 @@ func.func private @negative_copy_multidim_into_1D_strided_dynamic_offset(
 /// Non-unit copied dimension needs stride-based address computation.
 // CHECK-LABEL: func.func private @negative_copy_into_strided_dynamic_rc_stride(
 func.func private @negative_copy_into_strided_dynamic_rc_stride(%stride : index,
-  %src : memref<1x3x1xf32>, %dst : memref<1x3x11xf32>) {
+  %src : memref<1x3x1xf32>, %dst : memref<1x3x4xf32>) {
   // CHECK:      %reinterpret_cast = memref.reinterpret_cast %arg2
   %rc = memref.reinterpret_cast %dst
-    to offset: [0], sizes: [1, 3, 1], strides: [33, %stride, 1]
-    : memref<1x3x11xf32>
-      to memref<1x3x1xf32, strided<[33, ?, 1]>>
+    to offset: [0], sizes: [1, 3, 1], strides: [12, %stride, 1]
+    : memref<1x3x4xf32>
+      to memref<1x3x1xf32, strided<[12, ?, 1]>>
 
   // CHECK:      memref.copy %arg1, %reinterpret_cast
   // CHECK-NOT:  memref.load
   // CHECK-NOT:  memref.store
   memref.copy %src, %rc
     : memref<1x3x1xf32>
-      to memref<1x3x1xf32, strided<[33, ?, 1]>>
+      to memref<1x3x1xf32, strided<[12, ?, 1]>>
   return
 }
 



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