[llvm] [InstCombine] Optimize x * !x to 0 for vector #84608 (PR #84792)

[Yingwei Zheng via llvm-commits]

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@@ -198,6 +198,22 @@ Instruction *InstCombinerImpl::visitMul(BinaryOperator &I) {
   if (SimplifyAssociativeOrCommutative(I))
     return &I;
 
+  // mul (sext (icmp eq x, 0)), x -> 0
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dtcxzyw wrote:

You should fold `mul (sext X), Y` into `select X, -Y, 0` instead of simplifying the whole expression.



https://github.com/llvm/llvm-project/pull/84792