[llvm] [ConstantFold] Fold `tgamma` and `tgammaf` when the input parameter is a constant value. (PR #114065)

[via llvm-commits]

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@@ -3629,6 +3639,10 @@ bool llvm::isMathLibCallNoop(const CallBase *Call,
       case LibFunc_sqrtf:
         return Op.isNaN() || Op.isZero() || !Op.isNegative();
 
+      case LibFunc_tgamma:
+      case LibFunc_tgammaf:
+        return true;
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c8ef wrote:

Since we explicitly limit the input range, it should be safe to return *true* here. Ideally, this function could be integrated into the constant folding process.

https://github.com/llvm/llvm-project/pull/114065