[Mlir-commits] [mlir] [mlir][Vector] Update VectorEmulateNarrowType.cpp (3/N) (PR #123528)

llvmlistbot at llvm.org llvmlistbot at llvm.org
Sun Jan 19 13:00:20 PST 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-mlir

Author: Andrzej WarzyƄski (banach-space)

<details>
<summary>Changes</summary>

This is PR 3 in a series of N patches aimed at improving
"VectorEmulateNarrowType.cpp". This is mainly minor refactoring, no
major functional changes are made/added.

1. Replaces `isUnalignedEmulation` with `isFullyAligned`

Note, `isUnalignedEmulation` is always computed following a
"per-element-alignment" condition:
```cpp
// Check per-element alignment.
if (newBits % oldBits != 0) {
  return rewriter.notifyMatchFailure(op, "unalagined element types");
}

// (...)

bool isUnalignedEmulation = origElements % elementsPerContainerType != 0;
```

Given that `isUnalignedEmulation` captures only one of two conditions
required for "full alignment", it should be re-named as
`isPartiallyUnalignedEmulation`. Instead, I've flipped the condition and
renamed it as `isFullyAligned`:

```cpp
bool isFullyAligned = origElements % elementsPerContainerType == 0;
```

2. In addition:
  * Unifies various comments throughout the file (for consistency).
  * Adds new comments throughout the file and adds TODOs where high-level
    comments are missing.

---

Patch is 26.11 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/123528.diff


1 Files Affected:

- (modified) mlir/lib/Dialect/Vector/Transforms/VectorEmulateNarrowType.cpp (+133-105) 


``````````diff
diff --git a/mlir/lib/Dialect/Vector/Transforms/VectorEmulateNarrowType.cpp b/mlir/lib/Dialect/Vector/Transforms/VectorEmulateNarrowType.cpp
index 95064083b21d44..b6c109cc742eca 100644
--- a/mlir/lib/Dialect/Vector/Transforms/VectorEmulateNarrowType.cpp
+++ b/mlir/lib/Dialect/Vector/Transforms/VectorEmulateNarrowType.cpp
@@ -45,6 +45,10 @@ using namespace mlir;
 #define DBGSNL() (llvm::dbgs() << "\n")
 #define LDBG(X) LLVM_DEBUG(DBGS() << X << "\n")
 
+//===----------------------------------------------------------------------===//
+// Utils
+//===----------------------------------------------------------------------===//
+
 /// Returns a compressed mask for the emulated vector. For example, when
 /// emulating an eight-element `i8` vector with `i32` (i.e. when the source
 /// elements span two dest elements), this method compresses `vector<8xi1>`
@@ -282,13 +286,15 @@ emulatedVectorLoad(OpBuilder &rewriter, Location loc, Value base,
                    OpFoldResult linearizedIndices,
                    int64_t numEmultedElementsToLoad, Type origElemType,
                    Type emulatedElemType) {
-  auto scale = emulatedElemType.getIntOrFloatBitWidth() /
-               origElemType.getIntOrFloatBitWidth();
+  auto elementsPerContainerType = emulatedElemType.getIntOrFloatBitWidth() /
+                                  origElemType.getIntOrFloatBitWidth();
   auto newLoad = rewriter.create<vector::LoadOp>(
       loc, VectorType::get(numEmultedElementsToLoad, emulatedElemType), base,
       getValueOrCreateConstantIndexOp(rewriter, loc, linearizedIndices));
   return rewriter.create<vector::BitCastOp>(
-      loc, VectorType::get(numEmultedElementsToLoad * scale, origElemType),
+      loc,
+      VectorType::get(numEmultedElementsToLoad * elementsPerContainerType,
+                      origElemType),
       newLoad);
 }
 
@@ -298,6 +304,7 @@ namespace {
 // ConvertVectorStore
 //===----------------------------------------------------------------------===//
 
+// TODO: Document-me
 struct ConvertVectorStore final : OpConversionPattern<vector::StoreOp> {
   using OpConversionPattern::OpConversionPattern;
 
@@ -314,14 +321,14 @@ struct ConvertVectorStore final : OpConversionPattern<vector::StoreOp> {
     auto convertedType = cast<MemRefType>(adaptor.getBase().getType());
     Type oldElementType = op.getValueToStore().getType().getElementType();
     Type newElementType = convertedType.getElementType();
-    int srcBits = oldElementType.getIntOrFloatBitWidth();
-    int dstBits = newElementType.getIntOrFloatBitWidth();
+    int oldBits = oldElementType.getIntOrFloatBitWidth();
+    int newBits = newElementType.getIntOrFloatBitWidth();
 
-    if (dstBits % srcBits != 0) {
-      return rewriter.notifyMatchFailure(
-          op, "only dstBits % srcBits == 0 supported");
+    // Check per-element alignment.
+    if (newBits % oldBits != 0) {
+      return rewriter.notifyMatchFailure(op, "unalagined element types");
     }
-    int scale = dstBits / srcBits;
+    int elementsPerContainerType = newBits / oldBits;
 
     // Adjust the number of elements to store when emulating narrow types.
     // Here only the 1-D vector store is considered, and the N-D memref types
@@ -337,7 +344,7 @@ struct ConvertVectorStore final : OpConversionPattern<vector::StoreOp> {
     // vector<4xi8>
 
     auto origElements = op.getValueToStore().getType().getNumElements();
-    if (origElements % scale != 0)
+    if (origElements % elementsPerContainerType != 0)
       return failure();
 
     auto stridedMetadata =
@@ -346,13 +353,13 @@ struct ConvertVectorStore final : OpConversionPattern<vector::StoreOp> {
     OpFoldResult linearizedIndices;
     std::tie(std::ignore, linearizedIndices) =
         memref::getLinearizedMemRefOffsetAndSize(
-            rewriter, loc, srcBits, dstBits,
+            rewriter, loc, oldBits, newBits,
             stridedMetadata.getConstifiedMixedOffset(),
             stridedMetadata.getConstifiedMixedSizes(),
             stridedMetadata.getConstifiedMixedStrides(),
             getAsOpFoldResult(adaptor.getIndices()));
 
-    auto numElements = origElements / scale;
+    auto numElements = origElements / elementsPerContainerType;
     auto bitCast = rewriter.create<vector::BitCastOp>(
         loc, VectorType::get(numElements, newElementType),
         op.getValueToStore());
@@ -368,6 +375,7 @@ struct ConvertVectorStore final : OpConversionPattern<vector::StoreOp> {
 // ConvertVectorMaskedStore
 //===----------------------------------------------------------------------===//
 
+// TODO: Document-me
 struct ConvertVectorMaskedStore final
     : OpConversionPattern<vector::MaskedStoreOp> {
   using OpConversionPattern::OpConversionPattern;
@@ -385,17 +393,17 @@ struct ConvertVectorMaskedStore final
     auto convertedType = cast<MemRefType>(adaptor.getBase().getType());
     Type oldElementType = op.getValueToStore().getType().getElementType();
     Type newElementType = convertedType.getElementType();
-    int srcBits = oldElementType.getIntOrFloatBitWidth();
-    int dstBits = newElementType.getIntOrFloatBitWidth();
+    int oldBits = oldElementType.getIntOrFloatBitWidth();
+    int newBits = newElementType.getIntOrFloatBitWidth();
 
-    if (dstBits % srcBits != 0) {
-      return rewriter.notifyMatchFailure(
-          op, "only dstBits % srcBits == 0 supported");
+    // Check per-element alignment.
+    if (newBits % oldBits != 0) {
+      return rewriter.notifyMatchFailure(op, "unalagined element types");
     }
 
-    int scale = dstBits / srcBits;
+    int elementsPerContainerType = newBits / oldBits;
     int origElements = op.getValueToStore().getType().getNumElements();
-    if (origElements % scale != 0)
+    if (origElements % elementsPerContainerType != 0)
       return failure();
 
     auto stridedMetadata =
@@ -404,7 +412,7 @@ struct ConvertVectorMaskedStore final
     memref::LinearizedMemRefInfo linearizedInfo;
     std::tie(linearizedInfo, linearizedIndicesOfr) =
         memref::getLinearizedMemRefOffsetAndSize(
-            rewriter, loc, srcBits, dstBits,
+            rewriter, loc, oldBits, newBits,
             stridedMetadata.getConstifiedMixedOffset(),
             stridedMetadata.getConstifiedMixedSizes(),
             stridedMetadata.getConstifiedMixedStrides(),
@@ -444,12 +452,13 @@ struct ConvertVectorMaskedStore final
     //
     // FIXME: Make an example based on the comment above work (see #115460 for
     // reproducer).
-    FailureOr<Operation *> newMask =
-        getCompressedMaskOp(rewriter, loc, op.getMask(), origElements, scale);
+    FailureOr<Operation *> newMask = getCompressedMaskOp(
+        rewriter, loc, op.getMask(), origElements, elementsPerContainerType);
     if (failed(newMask))
       return failure();
 
-    auto numElements = (origElements + scale - 1) / scale;
+    auto numElements = (origElements + elementsPerContainerType - 1) /
+                       elementsPerContainerType;
     auto newType = VectorType::get(numElements, newElementType);
     auto passThru = rewriter.create<arith::ConstantOp>(
         loc, newType, rewriter.getZeroAttr(newType));
@@ -458,7 +467,8 @@ struct ConvertVectorMaskedStore final
         loc, newType, adaptor.getBase(), linearizedIndices,
         newMask.value()->getResult(0), passThru);
 
-    auto newBitCastType = VectorType::get(numElements * scale, oldElementType);
+    auto newBitCastType =
+        VectorType::get(numElements * elementsPerContainerType, oldElementType);
     Value valueToStore =
         rewriter.create<vector::BitCastOp>(loc, newBitCastType, newLoad);
     valueToStore = rewriter.create<arith::SelectOp>(
@@ -477,6 +487,7 @@ struct ConvertVectorMaskedStore final
 // ConvertVectorLoad
 //===----------------------------------------------------------------------===//
 
+// TODO: Document-me
 struct ConvertVectorLoad final : OpConversionPattern<vector::LoadOp> {
   using OpConversionPattern::OpConversionPattern;
 
@@ -493,14 +504,14 @@ struct ConvertVectorLoad final : OpConversionPattern<vector::LoadOp> {
     auto convertedType = cast<MemRefType>(adaptor.getBase().getType());
     Type oldElementType = op.getType().getElementType();
     Type newElementType = convertedType.getElementType();
-    int srcBits = oldElementType.getIntOrFloatBitWidth();
-    int dstBits = newElementType.getIntOrFloatBitWidth();
+    int oldBits = oldElementType.getIntOrFloatBitWidth();
+    int newBits = newElementType.getIntOrFloatBitWidth();
 
-    if (dstBits % srcBits != 0) {
-      return rewriter.notifyMatchFailure(
-          op, "only dstBits % srcBits == 0 supported");
+    // Check per-element alignment.
+    if (newBits % oldBits != 0) {
+      return rewriter.notifyMatchFailure(op, "unalagined element types");
     }
-    int scale = dstBits / srcBits;
+    int elementsPerContainerType = newBits / oldBits;
 
     // Adjust the number of elements to load when emulating narrow types,
     // and then cast back to the original type with vector.bitcast op.
@@ -532,7 +543,8 @@ struct ConvertVectorLoad final : OpConversionPattern<vector::LoadOp> {
     // compile time as they must be constants.
 
     auto origElements = op.getVectorType().getNumElements();
-    bool isUnalignedEmulation = origElements % scale != 0;
+    // Note, per-element-alignment was already verified above.
+    bool isFullyAligned = origElements % elementsPerContainerType == 0;
 
     auto stridedMetadata =
         rewriter.create<memref::ExtractStridedMetadataOp>(loc, op.getBase());
@@ -541,21 +553,21 @@ struct ConvertVectorLoad final : OpConversionPattern<vector::LoadOp> {
     memref::LinearizedMemRefInfo linearizedInfo;
     std::tie(linearizedInfo, linearizedIndices) =
         memref::getLinearizedMemRefOffsetAndSize(
-            rewriter, loc, srcBits, dstBits,
+            rewriter, loc, oldBits, newBits,
             stridedMetadata.getConstifiedMixedOffset(),
             stridedMetadata.getConstifiedMixedSizes(),
             stridedMetadata.getConstifiedMixedStrides(),
             getAsOpFoldResult(adaptor.getIndices()));
 
     std::optional<int64_t> foldedIntraVectorOffset =
-        isUnalignedEmulation
-            ? getConstantIntValue(linearizedInfo.intraDataOffset)
-            : 0;
+        isFullyAligned ? 0
+                       : getConstantIntValue(linearizedInfo.intraDataOffset);
 
     // Always load enough elements which can cover the original elements.
-    int64_t maxintraDataOffset = foldedIntraVectorOffset.value_or(scale - 1);
-    auto numElements =
-        llvm::divideCeil(maxintraDataOffset + origElements, scale);
+    int64_t maxintraDataOffset =
+        foldedIntraVectorOffset.value_or(elementsPerContainerType - 1);
+    auto numElements = llvm::divideCeil(maxintraDataOffset + origElements,
+                                        elementsPerContainerType);
     Value result =
         emulatedVectorLoad(rewriter, loc, adaptor.getBase(), linearizedIndices,
                            numElements, oldElementType, newElementType);
@@ -566,7 +578,7 @@ struct ConvertVectorLoad final : OpConversionPattern<vector::LoadOp> {
       result = dynamicallyExtractSubVector(
           rewriter, loc, dyn_cast<TypedValue<VectorType>>(result), resultVector,
           linearizedInfo.intraDataOffset, origElements);
-    } else if (isUnalignedEmulation) {
+    } else if (!isFullyAligned) {
       result =
           staticallyExtractSubvector(rewriter, loc, op.getType(), result,
                                      *foldedIntraVectorOffset, origElements);
@@ -580,6 +592,7 @@ struct ConvertVectorLoad final : OpConversionPattern<vector::LoadOp> {
 // ConvertVectorMaskedLoad
 //===----------------------------------------------------------------------===//
 
+// TODO: Document-me
 struct ConvertVectorMaskedLoad final
     : OpConversionPattern<vector::MaskedLoadOp> {
   using OpConversionPattern::OpConversionPattern;
@@ -596,14 +609,14 @@ struct ConvertVectorMaskedLoad final
     auto convertedType = cast<MemRefType>(adaptor.getBase().getType());
     Type oldElementType = op.getType().getElementType();
     Type newElementType = convertedType.getElementType();
-    int srcBits = oldElementType.getIntOrFloatBitWidth();
-    int dstBits = newElementType.getIntOrFloatBitWidth();
+    int oldBits = oldElementType.getIntOrFloatBitWidth();
+    int newBits = newElementType.getIntOrFloatBitWidth();
 
-    if (dstBits % srcBits != 0) {
-      return rewriter.notifyMatchFailure(
-          op, "only dstBits % srcBits == 0 supported");
+    // Check per-element alignment.
+    if (newBits % oldBits != 0) {
+      return rewriter.notifyMatchFailure(op, "unalagined element types");
     }
-    int scale = dstBits / srcBits;
+    int elementsPerContainerType = newBits / oldBits;
 
     // Adjust the number of elements to load when emulating narrow types,
     // and then cast back to the original type with vector.bitcast op.
@@ -649,7 +662,7 @@ struct ConvertVectorMaskedLoad final
     // subvector at the proper offset after bit-casting.
     auto origType = op.getVectorType();
     auto origElements = origType.getNumElements();
-    bool isUnalignedEmulation = origElements % scale != 0;
+    bool isUnalignedEmulation = origElements % elementsPerContainerType != 0;
 
     auto stridedMetadata =
         rewriter.create<memref::ExtractStridedMetadataOp>(loc, op.getBase());
@@ -657,7 +670,7 @@ struct ConvertVectorMaskedLoad final
     memref::LinearizedMemRefInfo linearizedInfo;
     std::tie(linearizedInfo, linearizedIndices) =
         memref::getLinearizedMemRefOffsetAndSize(
-            rewriter, loc, srcBits, dstBits,
+            rewriter, loc, oldBits, newBits,
             stridedMetadata.getConstifiedMixedOffset(),
             stridedMetadata.getConstifiedMixedSizes(),
             stridedMetadata.getConstifiedMixedStrides(),
@@ -668,18 +681,21 @@ struct ConvertVectorMaskedLoad final
             ? getConstantIntValue(linearizedInfo.intraDataOffset)
             : 0;
 
-    int64_t maxIntraDataOffset = foldedIntraVectorOffset.value_or(scale - 1);
-    FailureOr<Operation *> newMask = getCompressedMaskOp(
-        rewriter, loc, op.getMask(), origElements, scale, maxIntraDataOffset);
+    int64_t maxIntraDataOffset =
+        foldedIntraVectorOffset.value_or(elementsPerContainerType - 1);
+    FailureOr<Operation *> newMask =
+        getCompressedMaskOp(rewriter, loc, op.getMask(), origElements,
+                            elementsPerContainerType, maxIntraDataOffset);
     if (failed(newMask))
       return failure();
 
     Value passthru = op.getPassThru();
 
-    auto numElements =
-        llvm::divideCeil(maxIntraDataOffset + origElements, scale);
+    auto numElements = llvm::divideCeil(maxIntraDataOffset + origElements,
+                                        elementsPerContainerType);
     auto loadType = VectorType::get(numElements, newElementType);
-    auto newBitcastType = VectorType::get(numElements * scale, oldElementType);
+    auto newBitcastType =
+        VectorType::get(numElements * elementsPerContainerType, oldElementType);
 
     auto emptyVector = rewriter.create<arith::ConstantOp>(
         loc, newBitcastType, rewriter.getZeroAttr(newBitcastType));
@@ -706,8 +722,8 @@ struct ConvertVectorMaskedLoad final
         rewriter.create<vector::BitCastOp>(loc, newBitcastType, newLoad);
 
     Value mask = op.getMask();
-    auto newSelectMaskType =
-        VectorType::get(numElements * scale, rewriter.getI1Type());
+    auto newSelectMaskType = VectorType::get(
+        numElements * elementsPerContainerType, rewriter.getI1Type());
     // TODO: try to fold if op's mask is constant
     auto emptyMask = rewriter.create<arith::ConstantOp>(
         loc, newSelectMaskType, rewriter.getZeroAttr(newSelectMaskType));
@@ -741,6 +757,7 @@ struct ConvertVectorMaskedLoad final
 // ConvertVectorTransferRead
 //===----------------------------------------------------------------------===//
 
+// TODO: Document-me
 struct ConvertVectorTransferRead final
     : OpConversionPattern<vector::TransferReadOp> {
   using OpConversionPattern::OpConversionPattern;
@@ -758,18 +775,19 @@ struct ConvertVectorTransferRead final
     auto convertedType = cast<MemRefType>(adaptor.getSource().getType());
     Type oldElementType = op.getType().getElementType();
     Type newElementType = convertedType.getElementType();
-    int srcBits = oldElementType.getIntOrFloatBitWidth();
-    int dstBits = newElementType.getIntOrFloatBitWidth();
+    int oldBits = oldElementType.getIntOrFloatBitWidth();
+    int newBits = newElementType.getIntOrFloatBitWidth();
 
-    if (dstBits % srcBits != 0) {
-      return rewriter.notifyMatchFailure(
-          op, "only dstBits % srcBits == 0 supported");
+    // Check per-element alignment.
+    if (newBits % oldBits != 0) {
+      return rewriter.notifyMatchFailure(op, "unalagined element types");
     }
-    int scale = dstBits / srcBits;
+    int elementsPerContainerType = newBits / oldBits;
 
     auto origElements = op.getVectorType().getNumElements();
 
-    bool isUnalignedEmulation = origElements % scale != 0;
+    // Note, per-element-alignment was already verified above.
+    bool isFullyAligned = origElements % elementsPerContainerType == 0;
 
     auto newPadding = rewriter.create<arith::ExtUIOp>(loc, newElementType,
                                                       adaptor.getPadding());
@@ -781,20 +799,20 @@ struct ConvertVectorTransferRead final
     memref::LinearizedMemRefInfo linearizedInfo;
     std::tie(linearizedInfo, linearizedIndices) =
         memref::getLinearizedMemRefOffsetAndSize(
-            rewriter, loc, srcBits, dstBits,
+            rewriter, loc, oldBits, newBits,
             stridedMetadata.getConstifiedMixedOffset(),
             stridedMetadata.getConstifiedMixedSizes(),
             stridedMetadata.getConstifiedMixedStrides(),
             getAsOpFoldResult(adaptor.getIndices()));
 
     std::optional<int64_t> foldedIntraVectorOffset =
-        isUnalignedEmulation
-            ? getConstantIntValue(linearizedInfo.intraDataOffset)
-            : 0;
+        isFullyAligned ? 0
+                       : getConstantIntValue(linearizedInfo.intraDataOffset);
 
-    int64_t maxIntraDataOffset = foldedIntraVectorOffset.value_or(scale - 1);
-    auto numElements =
-        llvm::divideCeil(maxIntraDataOffset + origElements, scale);
+    int64_t maxIntraDataOffset =
+        foldedIntraVectorOffset.value_or(elementsPerContainerType - 1);
+    auto numElements = llvm::divideCeil(maxIntraDataOffset + origElements,
+                                        elementsPerContainerType);
 
     auto newRead = rewriter.create<vector::TransferReadOp>(
         loc, VectorType::get(numElements, newElementType), adaptor.getSource(),
@@ -802,7 +820,9 @@ struct ConvertVectorTransferRead final
         newPadding);
 
     auto bitCast = rewriter.create<vector::BitCastOp>(
-        loc, VectorType::get(numElements * scale, oldElementType), newRead);
+        loc,
+        VectorType::get(numElements * elementsPerContainerType, oldElementType),
+        newRead);
 
     Value result = bitCast->getResult(0);
     if (!foldedIntraVectorOffset) {
@@ -811,7 +831,7 @@ struct ConvertVectorTransferRead final
       result = dynamicallyExtractSubVector(rewriter, loc, bitCast, zeros,
                                            linearizedInfo.intraDataOffset,
                                            origElements);
-    } else if (isUnalignedEmulation) {
+    } else if (!isFullyAligned) {
       result =
           staticallyExtractSubvector(rewriter, loc, op.getType(), result,
                                      *foldedIntraVectorOffset, origElements);
@@ -1495,33 +1515,34 @@ struct RewriteExtOfBitCast : OpRewritePattern<ExtOpType> {
 /// LLVM to scramble with peephole optimizations. Templated to choose between
 /// signed and unsigned conversions.
 ///
-/// For example (signed):
+/// EXAMPLE 1 (signed):
 ///    arith.extsi %in : vector<8xi4> to vector<8xi32>
-///      is rewriten as
-///        %0 = vector.bitcast %in : vector<8xi4> to vector<4xi8>
-///        %1 = arith.shli %0, 4 : vector<4xi8>
-///        %2 = arith.shrsi %1, 4 : vector<4xi8>
-///        %3 = arith.shrsi %0, 4 : vector<4xi8>
-///        %4 = vector.interleave %2, %3 : vector<4xi8> -> vector<8xi8>
-///        %5 = arith.extsi %4 : vector<8xi8> to vector<8xi32>
+/// is rewriten ...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/123528


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