[llvm] [mlir] [ADT] Add implementations for mulhs and mulhu to APInt (PR #84609)

[Jakub Kuderski via llvm-commits]

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@@ -490,11 +487,8 @@ arith::MulUIExtendedOp::fold(FoldAdaptor adaptor,
           [](const APInt &a, const APInt &b) { return a * b; })) {
     // Invoke the constant fold helper again to calculate the 'high' result.
     Attribute highAttr = constFoldBinaryOp<IntegerAttr>(
-        adaptor.getOperands(), [](const APInt &a, const APInt &b) {
-          unsigned bitWidth = a.getBitWidth();
-          APInt fullProduct = a.zext(bitWidth * 2) * b.zext(bitWidth * 2);
-          return fullProduct.extractBits(bitWidth, bitWidth);
-        });
+        adaptor.getOperands(),
+        [](const APInt &a, const APInt &b) { return APIntOps::mulhu(a, b); });
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kuhar wrote:

Also here

https://github.com/llvm/llvm-project/pull/84609