[PATCH] D155461: [InstCombine] Keep !unpredictable when combining select+add

Tue Jul 18 00:48:34 PDT 2023

chfast added inline comments.

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Comment at: llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp:540
       Value *NewSel = Builder.CreateSelect(SI.getCondition(), Swapped ? C : OOp,
-                                           Swapped ? OOp : C);
+                                           Swapped ? OOp : C, "", &SI);
       if (isa<FPMathOperator>(&SI))
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goldstein.w.n wrote:
> chfast wrote:
> > I believe there are more case in the file where metadata copy is missed. I will try to identify them and create more tests cases. Can be in this review on later, depending on reviewers' suggestion.
> Are there any other binops you want to preserve this flag for?
I think it make sense for any binop because the condition of the select in this transformation remains unchanged (i.e. `!unpredictable` is still applicable).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D155461/new/

https://reviews.llvm.org/D155461