[Mlir-commits] [mlir] [MLIR][SCFToOpenMP] Fix crash when lowering vector reductions (PR #173978)

[Tom Eccles]

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@@ -261,54 +295,67 @@ static omp::DeclareReductionOp declareReduction(PatternRewriter &builder,
   // Match simple binary reductions that can be expressed with atomicrmw.
   Type type = reduce.getOperands()[reductionIndex].getType();
   Block &reduction = reduce.getReductions()[reductionIndex].front();
+
+  // Handle scalar element type extraction for vector bitwidth safety.
+  Type elType = type;
+  if (auto vecType = dyn_cast<VectorType>(type))
+    elType = vecType.getElementType();
+
+  // Helper to create splat (for vectors) or scalar attributes.
+  auto getAttr = [&](Attribute val) -> Attribute {
+    if (auto vecType = dyn_cast<VectorType>(type))
+      return DenseElementsAttr::get(vecType, val);
+    return val;
+  };
+
+  // Arithmetic Reductions
   if (matchSimpleReduction<arith::AddFOp, LLVM::FAddOp>(reduction)) {
-    omp::DeclareReductionOp decl =
-        createDecl(builder, symbolTable, reduce, reductionIndex,
-                   builder.getFloatAttr(type, 0.0));
-    return addAtomicRMW(builder, LLVM::AtomicBinOp::fadd, decl, reduce,
-                        reductionIndex);
+    auto decl = createDecl(builder, symbolTable, reduce, reductionIndex,
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tblah wrote:

Why did you switch to auto here? Spelling out the type is preferred 

https://github.com/llvm/llvm-project/pull/173978