[llvm] [InstCombine] Optimize powi(X, Y)/ (X * Z) with Ofast (PR #87047)

[via llvm-commits]

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@@ -580,15 +580,21 @@ Instruction *InstCombinerImpl::foldFPSignBitOps(BinaryOperator &I) {
 
 Instruction *InstCombinerImpl::foldPowiReassoc(BinaryOperator &I) {
   auto createPowiExpr = [](BinaryOperator &I, InstCombinerImpl &IC, Value *X,
-                           Value *Y, Value *Z) {
+                           Value *Y, Value *Z, bool UpdateUsers = true) {
     InstCombiner::BuilderTy &Builder = IC.Builder;
     Value *YZ = Builder.CreateAdd(Y, Z);
-    auto *NewPow = Builder.CreateIntrinsic(
+    Instruction *NewPow = Builder.CreateIntrinsic(
         Intrinsic::powi, {X->getType(), YZ->getType()}, {X, YZ}, &I);
-    return IC.replaceInstUsesWith(I, NewPow);
+    if (UpdateUsers)
+      return IC.replaceInstUsesWith(I, NewPow);
+    else
+      return NewPow;
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vfdff wrote:

Done

https://github.com/llvm/llvm-project/pull/87047