[Mlir-commits] [mlir] [mlir][linalg] Add Check for Reduction Operation in Contraction Body (PR #123134)

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@llvm/pr-subscribers-mlir-linalg

Author: Ayokunle Amodu (ayokunle321)

<details>
<summary>Changes</summary>

Fixes issue #<!-- -->122258.

Addresses a crash in the linalg-specialize-generic-ops pass caused by a null pointer dereference when attempting to specialize a linalg generic operation with a reduction iterator. The issue occurs because the pass assumes the presence of a valid reduction operation in the contraction body but does not verify its existence.

Cause: In the isContractionBody function, the getDefiningOp() method was returning nullptr for the yielded value when no operation explicitly defined the reduction result in the block. This led to an invalid dereference and a crash.

A check was added to ensure the presence of a valid reduction operation in the contraction body. The fix verifies that the function returns a false if getDefiningOp() returns a nullptr.

---
Full diff: https://github.com/llvm/llvm-project/pull/123134.diff


1 Files Affected:

- (modified) mlir/lib/Dialect/Linalg/IR/LinalgInterfaces.cpp (+6) 


``````````diff
diff --git a/mlir/lib/Dialect/Linalg/IR/LinalgInterfaces.cpp b/mlir/lib/Dialect/Linalg/IR/LinalgInterfaces.cpp
index caf9cdb3a3eb4f..14f8f9e8fdd3b4 100644
--- a/mlir/lib/Dialect/Linalg/IR/LinalgInterfaces.cpp
+++ b/mlir/lib/Dialect/Linalg/IR/LinalgInterfaces.cpp
@@ -281,6 +281,12 @@ bool mlir::linalg::detail::isContractionBody(
 
   Value yielded = getSourceSkipUnary(terminator->getOperand(0));
   Operation *reductionOp = yielded.getDefiningOp();
+
+  if (!reductionOp){
+    errs << "expected reduction op in body";
+    return false;
+  }
+
   if (reductionOp->getNumResults() != 1 || reductionOp->getNumOperands() != 2) {
     errs << "expected reduction op to be binary";
     return false;

``````````

</details>


https://github.com/llvm/llvm-project/pull/123134