[Mlir-commits] [mlir] [mlir][linalg] Preserve unsigned integer widening in named contraction vectorization (PR #216283)

[llvmlistbot at llvm.org]

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@@ -2069,6 +2069,29 @@ vectorizeAsLinalgContraction(RewriterBase &rewriter, VectorizationState &state,
     vecOperands.push_back(read);
   }
 
+  bool hasUnsignedCast =
+      TypeSwitch<Operation *, bool>(linalgOp.getOperation())
+          .Case<MatmulOp, BatchMatmulOp, BatchReduceMatmulOp, ContractOp>(
+              [](auto op) { return op.getCast() == TypeFn::cast_unsigned; })
+          .Default(false);
+  if (hasUnsignedCast) {
+    auto accType = dyn_cast<VectorType>(vecOperands[2].getType());
+    auto accElementType =
+        accType ? dyn_cast<IntegerType>(accType.getElementType()) : nullptr;
+    if (accElementType && accElementType.isSignless()) {
+      for (Value &operand : MutableArrayRef(vecOperands).take_front(2)) {
+        auto operandType = cast<VectorType>(operand.getType());
+        auto operandElementType =
+            dyn_cast<IntegerType>(operandType.getElementType());
+        if (!operandElementType || !operandElementType.isSignless() ||
+            operandElementType.getWidth() >= accElementType.getWidth())
+          continue;
+        operand = arith::ExtUIOp::create(
----------------
Pecco-314 wrote:

Currently, an explicit `extui` is needed to preserve unsigned widening semantics. For instance, this form is already recognized by the [Arm SVE I8MM](https://github.com/llvm/llvm-project/blob/main/mlir/lib/Dialect/ArmSVE/Transforms/LowerContractToSVEPatterns.cpp) (line 424).

I agree that adding per-operand promotion semantics to `vector.contract` may be better
long-term, but it is a broader change and probably belongs in a separate patch. I would prefer to keep this patch scoped as a correctness fix.

https://github.com/llvm/llvm-project/pull/216283