[Mlir-commits] [mlir] 1087c10 - [mlir][bufferize] Add hoist-dynamic-allocs-option to buffer-results-to-out-params (#160985)

llvmlistbot at llvm.org llvmlistbot at llvm.org
Mon Oct 6 02:05:26 PDT 2025


Author: lonely eagle
Date: 2025-10-06T17:05:21+08:00
New Revision: 1087c1079f870518b6bf6e2f6ed764d3e90611ae

URL: https://github.com/llvm/llvm-project/commit/1087c1079f870518b6bf6e2f6ed764d3e90611ae
DIFF: https://github.com/llvm/llvm-project/commit/1087c1079f870518b6bf6e2f6ed764d3e90611ae.diff

LOG: [mlir][bufferize] Add hoist-dynamic-allocs-option to buffer-results-to-out-params (#160985)

Add hoist-dynamic-allocs-option to buffer-results-to-out-params. This PR
supported that obtain the size of the dynamic shape memref through the
caller-callee relationship.

Added: 
    mlir/test/Transforms/buffer-results-to-out-params-hosit-dynamic-allocs.mlir
    mlir/test/Transforms/buffer-results-to-out-params-hosit-static-allocs.mlir

Modified: 
    mlir/include/mlir/Dialect/Bufferization/Transforms/Passes.h
    mlir/include/mlir/Dialect/Bufferization/Transforms/Passes.td
    mlir/lib/Dialect/Bufferization/Transforms/BufferResultsToOutParams.cpp

Removed: 
    mlir/test/Transforms/buffer-results-to-out-params-elim.mlir


################################################################################
diff  --git a/mlir/include/mlir/Dialect/Bufferization/Transforms/Passes.h b/mlir/include/mlir/Dialect/Bufferization/Transforms/Passes.h
index a2409f2796b94..67ac487d8226d 100644
--- a/mlir/include/mlir/Dialect/Bufferization/Transforms/Passes.h
+++ b/mlir/include/mlir/Dialect/Bufferization/Transforms/Passes.h
@@ -131,8 +131,8 @@ struct BufferResultsToOutParamsOpts {
   /// Allocator function: Generate a memref allocation with the given type.
   /// Since `promoteBufferResultsToOutParams` doesn't allow dynamically shaped
   /// results, we don't allow passing a range of values for dynamic dims.
-  using AllocationFn =
-      std::function<FailureOr<Value>(OpBuilder &, Location, MemRefType)>;
+  using AllocationFn = std::function<FailureOr<Value>(OpBuilder &, Location,
+                                                      MemRefType, ValueRange)>;
 
   /// Memcpy function: Generate a memcpy between two memrefs.
   using MemCpyFn =
@@ -147,8 +147,9 @@ struct BufferResultsToOutParamsOpts {
   /// Allocation function; used to allocate a memref.
   /// Default memref.alloc is used
   AllocationFn allocationFn = [](OpBuilder &builder, Location loc,
-                                 MemRefType type) {
-    return memref::AllocOp::create(builder, loc, type).getResult();
+                                 MemRefType type, ValueRange dynamicSizes) {
+    return memref::AllocOp::create(builder, loc, type, dynamicSizes)
+        .getResult();
   };
 
   /// Memcpy function; used to create a copy between two memrefs.
@@ -166,6 +167,10 @@ struct BufferResultsToOutParamsOpts {
   /// If true, the pass eliminates the memref.alloc and memcpy if the returned
   /// memref is allocated in the current function.
   bool hoistStaticAllocs = false;
+
+  /// If true, the pass eliminates the memref.alloc and memcpy if the returned
+  /// memref is allocated in the current function and has dynamic shape.
+  bool hoistDynamicAllocs = false;
 };
 
 /// Replace buffers that are returned from a function with an out parameter.

diff  --git a/mlir/include/mlir/Dialect/Bufferization/Transforms/Passes.td b/mlir/include/mlir/Dialect/Bufferization/Transforms/Passes.td
index a0d113c150c5e..cad44cb15f479 100644
--- a/mlir/include/mlir/Dialect/Bufferization/Transforms/Passes.td
+++ b/mlir/include/mlir/Dialect/Bufferization/Transforms/Passes.td
@@ -256,6 +256,8 @@ def BufferResultsToOutParamsPass
               "Add the attribute 'bufferize.result' to all output parameters.">,
        Option<"hoistStaticAllocs", "hoist-static-allocs", "bool",
               /*default=*/"false", "Hoist static allocations to call sites.">,
+       Option<"hoistDynamicAllocs", "hoist-dynamic-allocs", "bool",
+              /*default=*/"false", "Hoist dynamic allocations to call sites.">,
   ];
   let dependentDialects = ["memref::MemRefDialect"];
 }

diff  --git a/mlir/lib/Dialect/Bufferization/Transforms/BufferResultsToOutParams.cpp b/mlir/lib/Dialect/Bufferization/Transforms/BufferResultsToOutParams.cpp
index e30e094c28467..25f941dc16516 100644
--- a/mlir/lib/Dialect/Bufferization/Transforms/BufferResultsToOutParams.cpp
+++ b/mlir/lib/Dialect/Bufferization/Transforms/BufferResultsToOutParams.cpp
@@ -23,6 +23,8 @@ namespace bufferization {
 using namespace mlir;
 using AllocationFn = bufferization::BufferResultsToOutParamsOpts::AllocationFn;
 using MemCpyFn = bufferization::BufferResultsToOutParamsOpts::MemCpyFn;
+using AllocDynamicSizesMap =
+    llvm::DenseMap<func::FuncOp, SmallVector<SmallVector<Value>>>;
 
 /// Return `true` if the given MemRef type has a fully dynamic layout.
 static bool hasFullyDynamicLayoutMap(MemRefType type) {
@@ -43,6 +45,50 @@ static bool hasStaticIdentityLayout(MemRefType type) {
   return type.getLayout().isIdentity();
 }
 
+/// Return the dynamic shapes of the `memref` based on the defining op. If the
+/// complete dynamic shape fails to be captured, return an empty value.
+/// Currently, only function block arguments are supported for capturing.
+static SmallVector<Value> getDynamicSize(Value memref, func::FuncOp funcOp) {
+  Operation *defOp = memref.getDefiningOp();
+  if (!defOp)
+    return {};
+  auto operands = defOp->getOperands();
+  SmallVector<Value> dynamicSizes;
+  for (Value size : operands) {
+    if (!isa<IndexType>(size.getType()))
+      continue;
+
+    BlockArgument sizeSrc = dyn_cast<BlockArgument>(size);
+    if (!sizeSrc)
+      return {};
+    auto arguments = funcOp.getArguments();
+    auto iter = llvm::find(arguments, sizeSrc);
+    if (iter == arguments.end())
+      return {};
+    dynamicSizes.push_back(*iter);
+  }
+  return dynamicSizes;
+}
+
+/// Returns the dynamic sizes at the callee, through the call relationship
+/// between the caller and callee.
+static SmallVector<Value> mapDynamicSizeAtCaller(func::CallOp call,
+                                                 func::FuncOp callee,
+                                                 ValueRange dynamicSizes) {
+  SmallVector<Value> mappedDynamicSizes;
+  for (Value size : dynamicSizes) {
+    for (auto [src, dst] :
+         llvm::zip_first(call.getOperands(), callee.getArguments())) {
+      if (size != dst)
+        continue;
+      mappedDynamicSizes.push_back(src);
+    }
+  }
+  assert(mappedDynamicSizes.size() == dynamicSizes.size() &&
+         "could not find all dynamic sizes");
+  return mappedDynamicSizes;
+}
+
 // Updates the func op and entry block.
 //
 // Any args appended to the entry block are added to `appendedEntryArgs`.
@@ -109,6 +155,7 @@ updateFuncOp(func::FuncOp func,
 // the given out-params.
 static LogicalResult
 updateReturnOps(func::FuncOp func, ArrayRef<BlockArgument> appendedEntryArgs,
+                AllocDynamicSizesMap &map,
                 const bufferization::BufferResultsToOutParamsOpts &options) {
   auto res = func.walk([&](func::ReturnOp op) {
     SmallVector<Value, 6> copyIntoOutParams;
@@ -120,12 +167,22 @@ updateReturnOps(func::FuncOp func, ArrayRef<BlockArgument> appendedEntryArgs,
         keepAsReturnOperands.push_back(operand);
     }
     OpBuilder builder(op);
+    SmallVector<SmallVector<Value>> dynamicSizes;
     for (auto [orig, arg] : llvm::zip(copyIntoOutParams, appendedEntryArgs)) {
-      if (options.hoistStaticAllocs &&
+      bool hoistStaticAllocs =
+          options.hoistStaticAllocs &&
+          cast<MemRefType>(orig.getType()).hasStaticShape();
+      bool hoistDynamicAllocs =
+          options.hoistDynamicAllocs &&
+          !cast<MemRefType>(orig.getType()).hasStaticShape();
+      if ((hoistStaticAllocs || hoistDynamicAllocs) &&
           isa_and_nonnull<bufferization::AllocationOpInterface>(
-              orig.getDefiningOp()) &&
-          mlir::cast<MemRefType>(orig.getType()).hasStaticShape()) {
+              orig.getDefiningOp())) {
         orig.replaceAllUsesWith(arg);
+        if (hoistDynamicAllocs) {
+          SmallVector<Value> dynamicSize = getDynamicSize(orig, func);
+          dynamicSizes.push_back(dynamicSize);
+        }
         orig.getDefiningOp()->erase();
       } else {
         if (failed(options.memCpyFn(builder, op.getLoc(), orig, arg)))
@@ -134,6 +191,10 @@ updateReturnOps(func::FuncOp func, ArrayRef<BlockArgument> appendedEntryArgs,
     }
     func::ReturnOp::create(builder, op.getLoc(), keepAsReturnOperands);
     op.erase();
+    auto dynamicSizePair =
+        std::pair<func::FuncOp, SmallVector<SmallVector<Value>>>(func,
+                                                                 dynamicSizes);
+    map.insert(dynamicSizePair);
     return WalkResult::advance();
   });
   return failure(res.wasInterrupted());
@@ -142,7 +203,7 @@ updateReturnOps(func::FuncOp func, ArrayRef<BlockArgument> appendedEntryArgs,
 // Updates all CallOps in the scope of the given ModuleOp by allocating
 // temporary buffers for newly introduced out params.
 static LogicalResult
-updateCalls(ModuleOp module,
+updateCalls(ModuleOp module, const AllocDynamicSizesMap &map,
             const bufferization::BufferResultsToOutParamsOpts &options) {
   bool didFail = false;
   SymbolTable symtab(module);
@@ -166,8 +227,15 @@ updateCalls(ModuleOp module,
     }
     SmallVector<Value, 6> outParams;
     OpBuilder builder(op);
+    SmallVector<SmallVector<Value>> dynamicSizes = map.lookup(callee);
+    size_t dynamicSizesIndex = 0;
     for (Value memref : replaceWithOutParams) {
-      if (!cast<MemRefType>(memref.getType()).hasStaticShape()) {
+      SmallVector<Value> dynamicSize = dynamicSizes.size() > dynamicSizesIndex
+                                           ? dynamicSizes[dynamicSizesIndex]
+                                           : SmallVector<Value>();
+      bool memrefStaticShape =
+          cast<MemRefType>(memref.getType()).hasStaticShape();
+      if (!memrefStaticShape && dynamicSize.empty()) {
         op.emitError()
             << "cannot create out param for dynamically shaped result";
         didFail = true;
@@ -177,8 +245,15 @@ updateCalls(ModuleOp module,
       auto allocType =
           MemRefType::get(memrefType.getShape(), memrefType.getElementType(),
                           AffineMap(), memrefType.getMemorySpace());
+
+      if (memrefStaticShape) {
+        dynamicSize = {};
+      } else {
+        ++dynamicSizesIndex;
+        dynamicSize = mapDynamicSizeAtCaller(op, callee, dynamicSize);
+      }
       auto maybeOutParam =
-          options.allocationFn(builder, op.getLoc(), allocType);
+          options.allocationFn(builder, op.getLoc(), allocType, dynamicSize);
       if (failed(maybeOutParam)) {
         op.emitError() << "failed to create allocation op";
         didFail = true;
@@ -213,6 +288,9 @@ updateCalls(ModuleOp module,
 LogicalResult mlir::bufferization::promoteBufferResultsToOutParams(
     ModuleOp module,
     const bufferization::BufferResultsToOutParamsOpts &options) {
+  // It maps the shape source of the dynamic shape memref returned by each
+  // function.
+  AllocDynamicSizesMap map;
   for (auto func : module.getOps<func::FuncOp>()) {
     if (!options.filterFn(&func))
       continue;
@@ -222,11 +300,11 @@ LogicalResult mlir::bufferization::promoteBufferResultsToOutParams(
       return failure();
     if (func.isExternal())
       continue;
-    if (failed(updateReturnOps(func, appendedEntryArgs, options))) {
+    if (failed(updateReturnOps(func, appendedEntryArgs, map, options))) {
       return failure();
     }
   }
-  if (failed(updateCalls(module, options)))
+  if (failed(updateCalls(module, map, options)))
     return failure();
   return success();
 }
@@ -243,6 +321,8 @@ struct BufferResultsToOutParamsPass
       options.addResultAttribute = true;
     if (hoistStaticAllocs)
       options.hoistStaticAllocs = true;
+    if (hoistDynamicAllocs)
+      options.hoistDynamicAllocs = true;
 
     if (failed(bufferization::promoteBufferResultsToOutParams(getOperation(),
                                                               options)))

diff  --git a/mlir/test/Transforms/buffer-results-to-out-params-hosit-dynamic-allocs.mlir b/mlir/test/Transforms/buffer-results-to-out-params-hosit-dynamic-allocs.mlir
new file mode 100644
index 0000000000000..f33eb8e26fbce
--- /dev/null
+++ b/mlir/test/Transforms/buffer-results-to-out-params-hosit-dynamic-allocs.mlir
@@ -0,0 +1,79 @@
+// RUN: mlir-opt -allow-unregistered-dialect -p 'builtin.module(buffer-results-to-out-params{hoist-dynamic-allocs})' %s -split-input-file | FileCheck %s
+
+func.func private @single_alloc(%size : index) -> (memref<?xf32>) {
+  %alloc = memref.alloc(%size) : memref<?xf32>
+  return %alloc : memref<?xf32>
+}
+
+func.func @single_alloc_test(%size : index) {
+  %alloc = call @single_alloc(%size) : (index) -> (memref<?xf32>)
+  "test.sink"(%alloc) : (memref<?xf32>) -> ()
+}
+
+// CHECK-LABEL: func.func private @single_alloc(
+//  CHECK-SAME:   %{{.*}}: index,
+//  CHECK-SAME:   %{{.*}}: memref<?xf32>) {
+
+// CHECK-LABEL: func.func @single_alloc_test(
+//  CHECK-SAME:   %[[size:.*]]: index) {
+//       CHECK:   %[[alloc:.*]] = memref.alloc(%[[size]]) : memref<?xf32>
+//       CHECK:   call @single_alloc(%[[size]], %[[alloc]]) : (index, memref<?xf32>) -> ()
+//       CHECK:   "test.sink"(%[[alloc]]) : (memref<?xf32>) -> ()
+//       CHECK: }
+
+// -----
+
+func.func private @mult_alloc(%size0 : index, %size1 : index) -> (memref<?x?xf32>, memref<?xf32>) {
+  %alloc0 = memref.alloc(%size0, %size1) : memref<?x?xf32>
+  %alloc1 = memref.alloc(%size1) : memref<?xf32>
+  return %alloc0, %alloc1 : memref<?x?xf32>, memref<?xf32>
+}
+
+func.func @mult_alloc_test(%size0 : index, %size1: index) {
+  %alloc0, %alloc1 = call @mult_alloc(%size0, %size1) : (index, index) -> (memref<?x?xf32>, memref<?xf32>)
+  "test.sink"(%alloc0, %alloc1) : (memref<?x?xf32>, memref<?xf32>) -> ()
+}
+
+// CHECK-LABEL: func private @mult_alloc(
+//  CHECK-SAME:    %{{.*}}: index,  %{{.*}}: index,
+//  CHECK-SAME:    %{{.*}}: memref<?x?xf32>, %{{.*}}: memref<?xf32>) {
+
+// CHECK-LABEL: func @mult_alloc_test(
+//  CHECK-SAME:   %[[size0:.*]]: index,
+//  CHECK-SAME:   %[[size1:.*]]: index) {
+//       CHECK:   %[[alloc0:.*]] = memref.alloc(%[[size0]], %[[size1]]) : memref<?x?xf32>
+//       CHECK:   %[[alloc1:.*]] = memref.alloc(%[[size1]]) : memref<?xf32>
+//       CHECK:   call @mult_alloc(%[[size0]], %[[size1]], %[[alloc0]], %[[alloc1]]) : (index, index, memref<?x?xf32>, memref<?xf32>) -> ()
+//       CHECK:   "test.sink"(%[[alloc0]], %[[alloc1]]) : (memref<?x?xf32>, memref<?xf32>) -> ()
+//       CHECK: }
+
+
+// -----
+
+func.func private @complex_alloc(%size0 : index, %size1 : index) -> (memref<?x?xf32>, memref<4xf32>, memref<?xf32>) {
+  %alloc0 = memref.alloc(%size0, %size1) : memref<?x?xf32>
+  %alloc1 = memref.alloc() : memref<4xf32>
+  %alloc2 = memref.alloc(%size1) : memref<?xf32>
+  return %alloc0, %alloc1, %alloc2 : memref<?x?xf32>, memref<4xf32>, memref<?xf32>
+}
+
+func.func @complex_alloc_test(%size0 : index, %size1: index) {
+  %alloc0, %alloc1, %alloc2 = call @complex_alloc(%size0, %size1) : (index, index) -> (memref<?x?xf32>, memref<4xf32>, memref<?xf32>)
+  "test.sink"(%alloc0, %alloc1, %alloc2) : (memref<?x?xf32>, memref<4xf32>, memref<?xf32>) -> ()
+}
+
+// CHECK-LABEL: func private @complex_alloc(
+//  CHECK-SAME:   %{{.*}}: index, %{{.*}}: index,
+//  CHECK-SAME:   %{{.*}}: memref<?x?xf32>,
+//  CHECK-SAME:   %{{.*}}: memref<4xf32>,
+//  CHECK-SAME:   %{{.*}}: memref<?xf32>) {
+
+// CHECK-LABEL: func @complex_alloc_test(
+//  CHECK-SAME:   %[[size0:.*]]: index,
+//  CHECK-SAME:   %[[size1:.*]]: index) {
+//       CHECK:   %[[alloc0:.*]] = memref.alloc(%[[size0]], %[[size1]]) : memref<?x?xf32>
+//       CHECK:   %[[alloc1:.*]] = memref.alloc() : memref<4xf32>
+//       CHECK:   %[[alloc2:.*]] = memref.alloc(%[[size1]]) : memref<?xf32>
+//       CHECK:   call @complex_alloc(%[[size0]], %[[size1]], %[[alloc0]], %[[alloc1]], %[[alloc2]]) : (index, index, memref<?x?xf32>, memref<4xf32>, memref<?xf32>) -> ()
+//       CHECK:   "test.sink"(%[[alloc0]], %[[alloc1]], %[[alloc2]]) : (memref<?x?xf32>, memref<4xf32>, memref<?xf32>) -> ()
+//       CHECK: }

diff  --git a/mlir/test/Transforms/buffer-results-to-out-params-elim.mlir b/mlir/test/Transforms/buffer-results-to-out-params-hosit-static-allocs.mlir
similarity index 100%
rename from mlir/test/Transforms/buffer-results-to-out-params-elim.mlir
rename to mlir/test/Transforms/buffer-results-to-out-params-hosit-static-allocs.mlir


        


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