[PATCH] D158648: InstCombine: Introduce SimplifyDemandedUseFPClass

Wed Sep 13 05:53:31 PDT 2023

arsenm added inline comments.

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Comment at: llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp:1846
+    case Intrinsic::fabs:
+      if (SimplifyDemandedFPClass(I, 0, llvm::fabs(DemandedMask), Known,
+                                  Depth + 1))
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RKSimon wrote:
> nikic wrote:
> > It seems like this is correct, but only because `fabs(FPClassTest)` apparently does the exact opposite of what one would expect it to do. It's really `inverse_fabs()`.
> Do we need a llvm::inverse_fabs() ? Or at least a comment describing the behaviour
This probably just needs to be renamed, this is what it is. Not sure that's the right name, make_sign_insensitive or something maybe? unknown_sign?

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D158648/new/

https://reviews.llvm.org/D158648