[InstCombine] canonicalize fneg with llvm.sin
This is a follow-up to rL339604 which did the same transform
for a sin libcall. The handling of intrinsics vs. libcalls
is unfortunately scattered, so I'm just adding this next to
the existing transform for llvm.cos for now.
This should resolve PR38458:
https://bugs.llvm.org/show_bug.cgi?id=38458
If the call was already negated, the negates will cancel
each other out.
llvm-svn: 340952
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 2993f00..4755e85 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2124,16 +2124,25 @@
}
case Intrinsic::cos:
case Intrinsic::amdgcn_cos: {
- Value *SrcSrc;
+ Value *X;
Value *Src = II->getArgOperand(0);
- if (match(Src, m_FNeg(m_Value(SrcSrc))) ||
- match(Src, m_FAbs(m_Value(SrcSrc)))) {
+ if (match(Src, m_FNeg(m_Value(X))) || match(Src, m_FAbs(m_Value(X)))) {
// cos(-x) -> cos(x)
// cos(fabs(x)) -> cos(x)
- II->setArgOperand(0, SrcSrc);
+ II->setArgOperand(0, X);
return II;
}
-
+ break;
+ }
+ case Intrinsic::sin: {
+ Value *X;
+ if (match(II->getArgOperand(0), m_OneUse(m_FNeg(m_Value(X))))) {
+ // sin(-x) --> -sin(x)
+ Value *NewSin = Builder.CreateIntrinsic(Intrinsic::sin, { X }, II);
+ Instruction *FNeg = BinaryOperator::CreateFNeg(NewSin);
+ FNeg->copyFastMathFlags(II);
+ return FNeg;
+ }
break;
}
case Intrinsic::ppc_altivec_lvx: