[PATCH] D125746: [PowerPC] Treat llvm.fmuladd intrinsic as using CTR

[ChenZheng via Phabricator via llvm-commits]

shchenz added inline comments.


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Comment at: llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp:505
+              return true;
+            else
+              LLVM_FALLTHROUGH;
----------------
qiucf wrote:
> shchenz wrote:
> > no need for `else`. 
> > And why we need `LLVM_FALLTHROUGH`, I don't see any handling for `Intrinsic::fmuladd` in the switch block below, will `break` work?
> Here `FALLTHROUGH` sets `Opcode = ISD::FMA` for `fmuladd`. Code below checks whether `Opcode` is legal or custom, otherwise returns true.
Oh, yes, right. Then should `case Intrinsic::fma` have the same issue handled in `case Intrinsic::fmuladd` for double double? Or on the other hand, do we need the specific handling in `case Intrinsic::fmuladd`, will Opcode leagl or custom cover the check for type double double?


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Comment at: llvm/test/CodeGen/PowerPC/pr55463.ll:10
+; CHECK-NEXT:    stwu 1, -48(1)
+; CHECK-NEXT:    .cfi_def_cfa_offset 48
+; CHECK-NEXT:    .cfi_offset lr, 4
----------------
Can add a `nounwind` attribute for the function to simply the case a little bit.


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https://reviews.llvm.org/D125746