[Mlir-commits] [mlir] [mlir][vector] Canonicalize/fold 'order preserving' transposes (PR #135841)

[James Newling]

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@@ -5594,6 +5594,29 @@ LogicalResult ShapeCastOp::verify() {
   return success();
 }
 
+namespace {
+
+/// Return true if `transpose` does not permute a pair of non-unit dims.
+/// By `order preserving` we mean that the flattened versions of the input and
+/// output vectors are (numerically) identical. In other words `transpose` is
+/// effectively a shape cast.
+bool isOrderPreserving(TransposeOp transpose) {
+  ArrayRef<int64_t> permutation = transpose.getPermutation();
+  ArrayRef<int64_t> inShape = transpose.getSourceVectorType().getShape();
+  int64_t current = 0;
+  for (auto p : permutation) {
+    if (inShape[p] != 1) {
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newling wrote:

Oh yes, sorry you mentioned that earlier too. Will fix this. 

https://github.com/llvm/llvm-project/pull/135841