[llvm] [Transforms] Let amdgcn take advantage of sin(-x) --> -sin(x) (PR #79700)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: AtariDreams (AtariDreams)

<details>
<summary>Changes</summary>

We do it for amdgcn_cos, and we should do it for amdgcn_sin as well.

---
Full diff: https://github.com/llvm/llvm-project/pull/79700.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp (+3-2) 


``````````diff
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index a647be2d26c7613..ce54d49323dc6eb 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2497,11 +2497,12 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
     }
     break;
   }
-  case Intrinsic::sin: {
+  case Intrinsic::sin:
+  case Intrinsic::amdgcn_sin: {
     Value *X;
     if (match(II->getArgOperand(0), m_OneUse(m_FNeg(m_Value(X))))) {
       // sin(-x) --> -sin(x)
-      Value *NewSin = Builder.CreateUnaryIntrinsic(Intrinsic::sin, X, II);
+      Value *NewSin = Builder.CreateUnaryIntrinsic(IID, X, II);
       Instruction *FNeg = UnaryOperator::CreateFNeg(NewSin);
       FNeg->copyFastMathFlags(II);
       return FNeg;

``````````

</details>


https://github.com/llvm/llvm-project/pull/79700