From 2f79c6a4791aae6b02805c17bf77dfd030d3affc Mon Sep 17 00:00:00 2001
From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Mon, 24 Nov 2025 14:45:28 +0100
Subject: [PATCH] [MemRef] Remove memref.dim OffsetSizeAndStrideOpInterface
 folding

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.
---
 mlir/lib/Dialect/MemRef/IR/MemRefOps.cpp   |  7 -------
 mlir/test/Dialect/MemRef/canonicalize.mlir | 13 -------------
 2 files changed, 20 deletions(-)

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]]