[PATCH] D111638: [AArch64][SVE] Combine predicated FMUL/FADD into FMA

Mon Oct 25 02:41:03 PDT 2021

peterwaller-arm added inline comments.

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Comment at: llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp:720
+  llvm::FastMathFlags FMulFlags = cast<IntrinsicInst>(FMul)->getFastMathFlags();
+  if (!FAddFlags.allowContract() || !FMulFlags.allowContract())
+    return None;
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peterwaller-arm wrote:
> bsmith wrote:
> > Do we not care about Reassociation here also?
> My read of the LangRef suggests that contract allows an FMA contraction (But not two of them). So to my eyes this looks sufficient. Please can you clarify your concern?
Oh, on another reading I get it; 'contract' is like a weaker form of 'reassociation', and I also see what you're talking about with respect to the global flags.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D111638/new/

https://reviews.llvm.org/D111638