[mlir][vector] Support MaskableOpRewritePattern of op without a result.

[nujaa]

MaskableOpRewritePattern implements a wrapper of MatchAndRewrite as a solution to rewrite masked operators to prevent rewritepatterns to generate multiple ops inside a MaskOp (illegal).

This fix aims to target the case where the target op does not have a result (such as a transfer_write at memref_level). replaceOp would break if given an empty value.
Stems from : #91987

[nujaa]

CC @banach-space .

[llvmbot]

@llvm/pr-subscribers-mlir

@llvm/pr-subscribers-mlir-vector

Author: Hugo Trachino (nujaa)

Changes

MaskableOpRewritePattern implements a wrapper of MatchAndRewrite as a solution to rewrite masked operators to prevent rewritepatterns to generate multiple ops inside a MaskOp (illegal).

This fix aims to target the case where the target op does not have a result (such as a transfer_write at memref_level). replaceOp would break if given an empty value.
Stems from : #91987

---

Full diff: https://github.com/llvm/llvm-project/pull/92526.diff

1 Files Affected:

• (modified) mlir/include/mlir/Dialect/Vector/Utils/VectorUtils.h (+4-1)

diff --git a/mlir/include/mlir/Dialect/Vector/Utils/VectorUtils.h b/mlir/include/mlir/Dialect/Vector/Utils/VectorUtils.h
index 030be328e97fd..bf9694556f901 100644
--- a/mlir/include/mlir/Dialect/Vector/Utils/VectorUtils.h
+++ b/mlir/include/mlir/Dialect/Vector/Utils/VectorUtils.h
@@ -157,7 +157,10 @@ struct MaskableOpRewritePattern : OpRewritePattern<SourceOp> {
     if (failed(newOp))
       return failure();
 
-    rewriter.replaceOp(rootOp, *newOp);
+    if (rootOp->getNumResults() == 0 || *newOp == Value())
+      rewriter.eraseOp(rootOp);
+    else
+      rewriter.replaceOp(rootOp, *newOp);
     return success();
   }
 

[banach-space]

Thanks, now I realise what I was missing in #91987 (it was there, but I didn't notice). I think that it's fine to keep this within #91987 - that way it's easier to test.