[MemRef] Remove memref.dim OffsetSizeAndStrideOpInterface folding

[d0k]

OffsetSizeAndStrideOpInterface does not specify whether it's operating on the input or output shape and in fact different ops implement this in different ways, which is also why SubviewOp is special cased here.

This "marked as dynamic but not really dynamic" folding is better handled by shape inference, so just remove the bad fold.

[llvmbot]

@llvm/pr-subscribers-mlir-memref

@llvm/pr-subscribers-mlir

Author: Benjamin Kramer (d0k)

Changes

OffsetSizeAndStrideOpInterface does not specify whether it's operating on the input or output shape and in fact different ops implement this in different ways, which is also why SubviewOp is special cased here.

This "marked as dynamic but not really dynamic" folding is better handled by shape inference, so just remove the bad fold.

---

Full diff: https://github.com/llvm/llvm-project/pull/169327.diff

2 Files Affected:

• (modified) mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp (-7)
• (modified) mlir/test/Dialect/MemRef/canonicalize.mlir (-13)

diff --git a/mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp b/mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp
index 1c21a2f270da6..1035d7cb46e6e 100644
--- a/mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp
+++ b/mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp
@@ -1074,13 +1074,6 @@ OpFoldResult DimOp::fold(FoldAdaptor adaptor) {
     return subview.getDynamicSize(sourceIndex);
   }
 
-  if (auto sizeInterface =
-          dyn_cast_or_null<OffsetSizeAndStrideOpInterface>(definingOp)) {
-    assert(sizeInterface.isDynamicSize(unsignedIndex) &&
-           "Expected dynamic subview size");
-    return sizeInterface.getDynamicSize(unsignedIndex);
-  }
-
   // dim(memrefcast) -> dim
   if (succeeded(foldMemRefCast(*this)))
     return getResult();
diff --git a/mlir/test/Dialect/MemRef/canonicalize.mlir b/mlir/test/Dialect/MemRef/canonicalize.mlir
index 313090272ef90..e02717a2f5689 100644
--- a/mlir/test/Dialect/MemRef/canonicalize.mlir
+++ b/mlir/test/Dialect/MemRef/canonicalize.mlir
@@ -208,19 +208,6 @@ func.func @subview_negative_stride2(%arg0 : memref<7xf32>) -> memref<?xf32, stri
 
 // -----
 
-// CHECK-LABEL: func @dim_of_sized_view
-//  CHECK-SAME:   %{{[a-z0-9A-Z_]+}}: memref<?xi8>
-//  CHECK-SAME:   %[[SIZE:.[a-z0-9A-Z_]+]]: index
-//       CHECK:   return %[[SIZE]] : index
-func.func @dim_of_sized_view(%arg : memref<?xi8>, %size: index) -> index {
-  %c0 = arith.constant 0 : index
-  %0 = memref.reinterpret_cast %arg to offset: [0], sizes: [%size], strides: [1] : memref<?xi8> to memref<?xi8>
-  %1 = memref.dim %0, %c0 : memref<?xi8>
-  return %1 : index
-}
-
-// -----
-
 // CHECK-LABEL: func @no_fold_subview_negative_size
 //  CHECK:        %[[SUBVIEW:.+]] = memref.subview
 //  CHECK:        return %[[SUBVIEW]]