Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Revert "[mlir][memref] memref.subview: Verify result strides" #80116

Merged
merged 1 commit into from
Jan 31, 2024

Conversation

matthias-springer
Copy link
Member

Reverts #79865

I think there is a bug in the stride computation in SubViewOp::inferResultType. (Was already there before this change.)

Reverting this commit for now and updating the original pull request with a fix and more test cases.

@llvmbot
Copy link
Collaborator

llvmbot commented Jan 31, 2024

@llvm/pr-subscribers-mlir-gpu
@llvm/pr-subscribers-mlir-memref
@llvm/pr-subscribers-mlir-sparse

@llvm/pr-subscribers-mlir

Author: Matthias Springer (matthias-springer)

Changes

Reverts llvm/llvm-project#79865

I think there is a bug in the stride computation in SubViewOp::inferResultType. (Was already there before this change.)

Reverting this commit for now and updating the original pull request with a fix and more test cases.


Full diff: https://github.com/llvm/llvm-project/pull/80116.diff

5 Files Affected:

  • (modified) mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp (+52-68)
  • (modified) mlir/test/Dialect/GPU/decompose-memrefs.mlir (+3-3)
  • (modified) mlir/test/Dialect/MemRef/fold-memref-alias-ops.mlir (+6-6)
  • (modified) mlir/test/Dialect/MemRef/invalid.mlir (-9)
  • (modified) mlir/test/Integration/Dialect/SparseTensor/CPU/sparse_rewrite_sort_coo.mlir (+4-4)
diff --git a/mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp b/mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp
index f43217f6f27ae..8b5765b7f8dba 100644
--- a/mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp
+++ b/mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp
@@ -917,7 +917,7 @@ static std::map<int64_t, unsigned> getNumOccurences(ArrayRef<int64_t> vals) {
 /// This accounts for cases where there are multiple unit-dims, but only a
 /// subset of those are dropped. For MemRefTypes these can be disambiguated
 /// using the strides. If a dimension is dropped the stride must be dropped too.
-static FailureOr<llvm::SmallBitVector>
+static std::optional<llvm::SmallBitVector>
 computeMemRefRankReductionMask(MemRefType originalType, MemRefType reducedType,
                                ArrayRef<OpFoldResult> sizes) {
   llvm::SmallBitVector unusedDims(originalType.getRank());
@@ -941,7 +941,7 @@ computeMemRefRankReductionMask(MemRefType originalType, MemRefType reducedType,
           getStridesAndOffset(originalType, originalStrides, originalOffset)) ||
       failed(
           getStridesAndOffset(reducedType, candidateStrides, candidateOffset)))
-    return failure();
+    return std::nullopt;
 
   // For memrefs, a dimension is truly dropped if its corresponding stride is
   // also dropped. This is particularly important when more than one of the dims
@@ -976,22 +976,22 @@ computeMemRefRankReductionMask(MemRefType originalType, MemRefType reducedType,
         candidateStridesNumOccurences[originalStride]) {
       // This should never happen. Cant have a stride in the reduced rank type
       // that wasnt in the original one.
-      return failure();
+      return std::nullopt;
     }
   }
 
   if ((int64_t)unusedDims.count() + reducedType.getRank() !=
       originalType.getRank())
-    return failure();
+    return std::nullopt;
   return unusedDims;
 }
 
 llvm::SmallBitVector SubViewOp::getDroppedDims() {
   MemRefType sourceType = getSourceType();
   MemRefType resultType = getType();
-  FailureOr<llvm::SmallBitVector> unusedDims =
+  std::optional<llvm::SmallBitVector> unusedDims =
       computeMemRefRankReductionMask(sourceType, resultType, getMixedSizes());
-  assert(succeeded(unusedDims) && "unable to find unused dims of subview");
+  assert(unusedDims && "unable to find unused dims of subview");
   return *unusedDims;
 }
 
@@ -2745,7 +2745,7 @@ void SubViewOp::build(OpBuilder &b, OperationState &result, Value source,
 /// For ViewLikeOpInterface.
 Value SubViewOp::getViewSource() { return getSource(); }
 
-/// Return true if `t1` and `t2` have equal offsets (both dynamic or of same
+/// Return true if t1 and t2 have equal offsets (both dynamic or of same
 /// static value).
 static bool haveCompatibleOffsets(MemRefType t1, MemRefType t2) {
   int64_t t1Offset, t2Offset;
@@ -2755,41 +2755,56 @@ static bool haveCompatibleOffsets(MemRefType t1, MemRefType t2) {
   return succeeded(res1) && succeeded(res2) && t1Offset == t2Offset;
 }
 
-/// Return true if `t1` and `t2` have equal strides (both dynamic or of same
-/// static value).
-static bool haveCompatibleStrides(MemRefType t1, MemRefType t2) {
-  int64_t t1Offset, t2Offset;
-  SmallVector<int64_t> t1Strides, t2Strides;
-  auto res1 = getStridesAndOffset(t1, t1Strides, t1Offset);
-  auto res2 = getStridesAndOffset(t2, t2Strides, t2Offset);
-  if (failed(res1) || failed(res2))
-    return false;
-  for (auto [s1, s2] : llvm::zip_equal(t1Strides, t2Strides))
-    if (s1 != s2)
-      return false;
-  return true;
+/// Checks if `original` Type type can be rank reduced to `reduced` type.
+/// This function is slight variant of `is subsequence` algorithm where
+/// not matching dimension must be 1.
+static SliceVerificationResult
+isRankReducedMemRefType(MemRefType originalType,
+                        MemRefType candidateRankReducedType,
+                        ArrayRef<OpFoldResult> sizes) {
+  auto partialRes = isRankReducedType(originalType, candidateRankReducedType);
+  if (partialRes != SliceVerificationResult::Success)
+    return partialRes;
+
+  auto optionalUnusedDimsMask = computeMemRefRankReductionMask(
+      originalType, candidateRankReducedType, sizes);
+
+  // Sizes cannot be matched in case empty vector is returned.
+  if (!optionalUnusedDimsMask)
+    return SliceVerificationResult::LayoutMismatch;
+
+  if (originalType.getMemorySpace() !=
+      candidateRankReducedType.getMemorySpace())
+    return SliceVerificationResult::MemSpaceMismatch;
+
+  // No amount of stride dropping can reconcile incompatible offsets.
+  if (!haveCompatibleOffsets(originalType, candidateRankReducedType))
+    return SliceVerificationResult::LayoutMismatch;
+
+  return SliceVerificationResult::Success;
 }
 
+template <typename OpTy>
 static LogicalResult produceSubViewErrorMsg(SliceVerificationResult result,
-                                            Operation *op, Type expectedType) {
+                                            OpTy op, Type expectedType) {
   auto memrefType = llvm::cast<ShapedType>(expectedType);
   switch (result) {
   case SliceVerificationResult::Success:
     return success();
   case SliceVerificationResult::RankTooLarge:
-    return op->emitError("expected result rank to be smaller or equal to ")
+    return op.emitError("expected result rank to be smaller or equal to ")
            << "the source rank. ";
   case SliceVerificationResult::SizeMismatch:
-    return op->emitError("expected result type to be ")
+    return op.emitError("expected result type to be ")
            << expectedType
            << " or a rank-reduced version. (mismatch of result sizes) ";
   case SliceVerificationResult::ElemTypeMismatch:
-    return op->emitError("expected result element type to be ")
+    return op.emitError("expected result element type to be ")
            << memrefType.getElementType();
   case SliceVerificationResult::MemSpaceMismatch:
-    return op->emitError("expected result and source memory spaces to match.");
+    return op.emitError("expected result and source memory spaces to match.");
   case SliceVerificationResult::LayoutMismatch:
-    return op->emitError("expected result type to be ")
+    return op.emitError("expected result type to be ")
            << expectedType
            << " or a rank-reduced version. (mismatch of result layout) ";
   }
@@ -2811,46 +2826,13 @@ LogicalResult SubViewOp::verify() {
   if (!isStrided(baseType))
     return emitError("base type ") << baseType << " is not strided";
 
-  // Compute the expected result type, assuming that there are no rank
-  // reductions.
-  auto expectedType = cast<MemRefType>(SubViewOp::inferResultType(
-      baseType, getStaticOffsets(), getStaticSizes(), getStaticStrides()));
-
-  // Verify all properties of a shaped type: rank, element type and dimension
-  // sizes. This takes into account potential rank reductions.
-  auto shapedTypeVerification = isRankReducedType(
-      /*originalType=*/expectedType, /*candidateReducedType=*/subViewType);
-  if (shapedTypeVerification != SliceVerificationResult::Success)
-    return produceSubViewErrorMsg(shapedTypeVerification, *this, expectedType);
-
-  // Make sure that the memory space did not change.
-  if (expectedType.getMemorySpace() != subViewType.getMemorySpace())
-    return produceSubViewErrorMsg(SliceVerificationResult::MemSpaceMismatch,
-                                  *this, expectedType);
-
-  // Verify the offset of the layout map.
-  if (!haveCompatibleOffsets(expectedType, subViewType))
-    return produceSubViewErrorMsg(SliceVerificationResult::LayoutMismatch,
-                                  *this, expectedType);
-
-  // The only thing that's left to verify now are the strides. First, compute
-  // the unused dimensions due to rank reductions. We have to look at sizes and
-  // strides to decide which dimensions were dropped. This function also
-  // partially verifies strides in case of rank reductions.
-  auto unusedDims = computeMemRefRankReductionMask(expectedType, subViewType,
-                                                   getMixedSizes());
-  if (failed(unusedDims))
-    return produceSubViewErrorMsg(SliceVerificationResult::LayoutMismatch,
-                                  *this, expectedType);
-
-  // Strides must match if there are no rank reductions.
-  // TODO: Verify strides when there are rank reductions. Strides are partially
-  // checked in `computeMemRefRankReductionMask`.
-  if (unusedDims->none() && !haveCompatibleStrides(expectedType, subViewType))
-    return produceSubViewErrorMsg(SliceVerificationResult::LayoutMismatch,
-                                  *this, expectedType);
+  // Verify result type against inferred type.
+  auto expectedType = SubViewOp::inferResultType(
+      baseType, getStaticOffsets(), getStaticSizes(), getStaticStrides());
 
-  return success();
+  auto result = isRankReducedMemRefType(llvm::cast<MemRefType>(expectedType),
+                                        subViewType, getMixedSizes());
+  return produceSubViewErrorMsg(result, *this, expectedType);
 }
 
 raw_ostream &mlir::operator<<(raw_ostream &os, const Range &range) {
@@ -2900,9 +2882,11 @@ static MemRefType getCanonicalSubViewResultType(
     ArrayRef<OpFoldResult> mixedSizes, ArrayRef<OpFoldResult> mixedStrides) {
   auto nonRankReducedType = llvm::cast<MemRefType>(SubViewOp::inferResultType(
       sourceType, mixedOffsets, mixedSizes, mixedStrides));
-  FailureOr<llvm::SmallBitVector> unusedDims = computeMemRefRankReductionMask(
-      currentSourceType, currentResultType, mixedSizes);
-  if (failed(unusedDims))
+  std::optional<llvm::SmallBitVector> unusedDims =
+      computeMemRefRankReductionMask(currentSourceType, currentResultType,
+                                     mixedSizes);
+  // Return nullptr as failure mode.
+  if (!unusedDims)
     return nullptr;
 
   auto layout = llvm::cast<StridedLayoutAttr>(nonRankReducedType.getLayout());
diff --git a/mlir/test/Dialect/GPU/decompose-memrefs.mlir b/mlir/test/Dialect/GPU/decompose-memrefs.mlir
index 56fc9a66b7ace..d714010d0f254 100644
--- a/mlir/test/Dialect/GPU/decompose-memrefs.mlir
+++ b/mlir/test/Dialect/GPU/decompose-memrefs.mlir
@@ -119,7 +119,7 @@ func.func @decompose_subview(%arg0 : memref<?x?x?xf32>) {
 //       CHECK:  %[[IDX1:.*]] = affine.apply #[[MAP1]]()[%[[STRIDES]]#1]
 //       CHECK:  %[[IDX2:.*]] = affine.apply #[[MAP2]]()[%[[TX]], %[[STRIDES]]#0, %[[TY]], %[[STRIDES]]#1, %[[TZ]]]
 //       CHECK:  %[[PTR:.*]] = memref.reinterpret_cast %[[BASE]] to offset: [%[[IDX2]]], sizes: [%{{.*}}, %{{.*}}, %{{.*}}], strides: [%[[IDX]], %[[IDX1]], 4]
-//       CHECK:  "test.test"(%[[PTR]]) : (memref<?x?x?xf32, strided<[?, ?, 4], offset: ?>>) -> ()
+//       CHECK:  "test.test"(%[[PTR]]) : (memref<?x?x?xf32, strided<[?, ?, ?], offset: ?>>) -> ()
 func.func @decompose_subview_strided(%arg0 : memref<?x?x?xf32>) {
   %c0 = arith.constant 0 : index
   %c1 = arith.constant 1 : index
@@ -129,8 +129,8 @@ func.func @decompose_subview_strided(%arg0 : memref<?x?x?xf32>) {
   %block_dim2 = memref.dim %arg0, %c2 : memref<?x?x?xf32>
   gpu.launch blocks(%bx, %by, %bz) in (%grid_x = %c1, %grid_y = %c1, %grid_z = %c1)
              threads(%tx, %ty, %tz) in (%block_x = %block_dim0, %block_y = %block_dim1, %block_z = %block_dim2) {
-    %res = memref.subview %arg0[%tx, %ty, %tz] [%c2, %c2, %c2] [2, 3, 4] : memref<?x?x?xf32> to memref<?x?x?xf32, strided<[?, ?, 4], offset: ?>>
-    "test.test"(%res) : (memref<?x?x?xf32, strided<[?, ?, 4], offset: ?>>) -> ()
+    %res = memref.subview %arg0[%tx, %ty, %tz] [%c2, %c2, %c2] [2, 3, 4] : memref<?x?x?xf32> to memref<?x?x?xf32, strided<[?, ?, ?], offset: ?>>
+    "test.test"(%res) : (memref<?x?x?xf32, strided<[?, ?, ?], offset: ?>>) -> ()
     gpu.terminator
   }
   return
diff --git a/mlir/test/Dialect/MemRef/fold-memref-alias-ops.mlir b/mlir/test/Dialect/MemRef/fold-memref-alias-ops.mlir
index 3407bdbc7c8f9..96b72e042b9e0 100644
--- a/mlir/test/Dialect/MemRef/fold-memref-alias-ops.mlir
+++ b/mlir/test/Dialect/MemRef/fold-memref-alias-ops.mlir
@@ -595,9 +595,9 @@ func.func @subview_of_subview(%m: memref<1x1024xf32, 3>, %pos: index)
 {
   %0 = memref.subview %m[3, %pos] [1, 2] [1, 1]
       : memref<1x1024xf32, 3>
-        to memref<1x2xf32, strided<[1024, 1], offset: ?>, 3>
+        to memref<1x2xf32, strided<[1024, 2], offset: ?>, 3>
   %1 = memref.subview %0[1, 2] [1, 1] [1, 1]
-      : memref<1x2xf32, strided<[1024, 1], offset: ?>, 3>
+      : memref<1x2xf32, strided<[1024, 2], offset: ?>, 3>
         to memref<f32, strided<[], offset: ?>, 3>
   return %1 : memref<f32, strided<[], offset: ?>, 3>
 }
@@ -675,9 +675,9 @@ func.func @fold_gpu_subgroup_mma_store_matrix_1d(%dst: memref<?xvector<4xf32>>,
 // CHECK-LABEL: func.func @fold_gpu_subgroup_mma_load_matrix_2d
 //  CHECK-SAME: %[[SRC:.+]]: memref<128x128xf32>
 func.func @fold_gpu_subgroup_mma_load_matrix_2d(%arg0 : memref<128x128xf32>, %arg1 : index, %arg2 : index, %arg3 : index, %arg4 : index) -> !gpu.mma_matrix<16x16xf16, "COp"> {
-  %subview = memref.subview %arg0[%arg1, %arg2][64, 32][2, 1] : memref<128x128xf32> to memref<64x32xf32, strided<[256, 1], offset: ?>>
+  %subview = memref.subview %arg0[%arg1, %arg2][64, 32][2, 1] : memref<128x128xf32> to memref<64x32xf32, strided<[64, 1], offset: ?>>
   // CHECK: gpu.subgroup_mma_load_matrix %[[SRC]][{{.+}}] {leadDimension = 32 : index} : memref<128x128xf32> -> !gpu.mma_matrix<16x16xf16, "COp">
-  %matrix = gpu.subgroup_mma_load_matrix %subview[%arg3, %arg4] {leadDimension = 32 : index} : memref<64x32xf32, strided<[256, 1], offset: ?>> -> !gpu.mma_matrix<16x16xf16, "COp">
+  %matrix = gpu.subgroup_mma_load_matrix %subview[%arg3, %arg4] {leadDimension = 32 : index} : memref<64x32xf32, strided<[64, 1], offset: ?>> -> !gpu.mma_matrix<16x16xf16, "COp">
   return %matrix : !gpu.mma_matrix<16x16xf16, "COp">
 }
 
@@ -686,9 +686,9 @@ func.func @fold_gpu_subgroup_mma_load_matrix_2d(%arg0 : memref<128x128xf32>, %ar
 // CHECK-LABEL: func.func @fold_gpu_subgroup_mma_load_matrix_2d
 //  CHECK-SAME: %[[DST:.+]]: memref<128x128xf32>
 func.func @fold_gpu_subgroup_mma_load_matrix_2d(%arg0 : memref<128x128xf32>, %arg1 : index, %arg2 : index, %arg3 : index, %arg4 : index, %matrix: !gpu.mma_matrix<16x16xf16, "COp">) {
-  %subview = memref.subview %arg0[%arg1, %arg2][64, 32][2, 1] : memref<128x128xf32> to memref<64x32xf32, strided<[256, 1], offset: ?>>
+  %subview = memref.subview %arg0[%arg1, %arg2][64, 32][2, 1] : memref<128x128xf32> to memref<64x32xf32, strided<[64, 1], offset: ?>>
   // CHECK: gpu.subgroup_mma_store_matrix %{{.+}}, %[[DST]][{{.+}}] {leadDimension = 32 : index} : !gpu.mma_matrix<16x16xf16, "COp">, memref<128x128xf32>
-  gpu.subgroup_mma_store_matrix %matrix, %subview[%arg3, %arg4] {leadDimension = 32 : index} :  !gpu.mma_matrix<16x16xf16, "COp">, memref<64x32xf32, strided<[256, 1], offset: ?>>
+  gpu.subgroup_mma_store_matrix %matrix, %subview[%arg3, %arg4] {leadDimension = 32 : index} :  !gpu.mma_matrix<16x16xf16, "COp">, memref<64x32xf32, strided<[64, 1], offset: ?>>
   return
 }
 
diff --git a/mlir/test/Dialect/MemRef/invalid.mlir b/mlir/test/Dialect/MemRef/invalid.mlir
index be60a3dcb1b20..7bb7a2affcbd1 100644
--- a/mlir/test/Dialect/MemRef/invalid.mlir
+++ b/mlir/test/Dialect/MemRef/invalid.mlir
@@ -1073,12 +1073,3 @@ func.func @dim_0_ranked(%arg : memref<f32>, %arg1 : index) {
   memref.dim %arg, %arg1 : memref<f32> // expected-error {{'memref.dim' op operand #0 must be unranked.memref of any type values or non-0-ranked.memref of any type values, but got 'memref<f32>'}}
   return
 }
-
-// -----
-
-func.func @subview_invalid_strides(%m: memref<7x22x333x4444xi32>) {
-  // expected-error @below{{expected result type to be 'memref<7x11x333x4444xi32, strided<[32556744, 2959704, 4444, 1]>>' or a rank-reduced version. (mismatch of result layout)}}
-  %subview = memref.subview %m[0, 0, 0, 0] [7, 11, 333, 4444] [1, 2, 1, 1]
-      : memref<7x22x333x4444xi32> to memref<7x11x333x4444xi32>
-  return
-}
diff --git a/mlir/test/Integration/Dialect/SparseTensor/CPU/sparse_rewrite_sort_coo.mlir b/mlir/test/Integration/Dialect/SparseTensor/CPU/sparse_rewrite_sort_coo.mlir
index e7dd0ad32a243..3773cca9c8d69 100644
--- a/mlir/test/Integration/Dialect/SparseTensor/CPU/sparse_rewrite_sort_coo.mlir
+++ b/mlir/test/Integration/Dialect/SparseTensor/CPU/sparse_rewrite_sort_coo.mlir
@@ -88,10 +88,10 @@ module {
     // Prepare a buffer for x0, x1, x2, y0 and a buffer for y1.
     %xys = memref.alloc() : memref<20xi32>
     %xy = memref.cast %xys : memref<20xi32> to memref<?xi32>
-    %x0 = memref.subview %xy[%i0][%i5][4] : memref<?xi32> to memref<?xi32, strided<[4], offset: ?>>
-    %x1 = memref.subview %xy[%i1][%i5][4] : memref<?xi32> to memref<?xi32, strided<[4], offset: ?>>
-    %x2 = memref.subview %xy[%i2][%i5][4] : memref<?xi32> to memref<?xi32, strided<[4], offset: ?>>
-    %y0 = memref.subview %xy[%i3][%i5][4] : memref<?xi32> to memref<?xi32, strided<[4], offset: ?>>
+    %x0 = memref.subview %xy[%i0][%i5][%i4] : memref<?xi32> to memref<?xi32, strided<[4], offset: ?>>
+    %x1 = memref.subview %xy[%i1][%i5][%i4] : memref<?xi32> to memref<?xi32, strided<[4], offset: ?>>
+    %x2 = memref.subview %xy[%i2][%i5][%i4] : memref<?xi32> to memref<?xi32, strided<[4], offset: ?>>
+    %y0 = memref.subview %xy[%i3][%i5][%i4] : memref<?xi32> to memref<?xi32, strided<[4], offset: ?>>
     %y1s = memref.alloc() : memref<7xi32>
     %y1 = memref.cast %y1s : memref<7xi32> to memref<?xi32>
 

@matthias-springer matthias-springer merged commit 96c907d into main Jan 31, 2024
7 of 8 checks passed
@matthias-springer matthias-springer deleted the revert-79865-subview_verify_strides branch January 31, 2024 08:35
matthias-springer added a commit to matthias-springer/llvm-project that referenced this pull request Jan 31, 2024
The `memref.subview` verifier currently checks result shape, element type, memory space and offset of the result type. However, the strides of the result type are currently not verified. This commit adds verification of result strides for non-rank reducing ops and fixes invalid IR in test cases.

Verification of result strides for ops with rank reductions is more complex (and there could be multiple possible result types). That is left for a separate commit.

Also refactor the implementation a bit:
* If `computeMemRefRankReductionMask` could not compute the dropped dimensions, there must be something wrong with the op. Return `FailureOr` instead of `std::optional`.
* `isRankReducedMemRefType` did much more than just checking whether the op has rank reductions or not. Inline the implementation into the verifier and add better comments.
* `produceSubViewErrorMsg` does not have to be templatized.
* Fix comment and add additional assert to `ExpandStridedMetadata.cpp`, to make sure that the memref.subview verifier is in sync with the memref.subview -> memref.reinterpret_cast lowering.

Note: This change is identical to llvm#79865, but with a fixed comment and an additional assert in `ExpandStridedMetadata.cpp`. (I reverted llvm#79865 in llvm#80116, but the implementation was actually correct, just the comment in `ExpandStridedMetadata.cpp` was confusing.)
@aartbik
Copy link
Contributor

aartbik commented Jan 31, 2024

noted

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
Projects
None yet
Development

Successfully merging this pull request may close these issues.

3 participants