[llvm] [SimplifyLibCalls] Constant fold `remquo` (PR #99647)

[Matt Arsenault via llvm-commits]

================
@@ -3018,6 +3018,39 @@ void LibCallSimplifier::classifyArgUse(
   }
 }
 
+/// Constant folds remquo
+Value *LibCallSimplifier::optimizeRemquo(CallInst *CI, IRBuilderBase &B) {
+  const APFloat *X, *Y;
+  if (!match(CI->getArgOperand(0), m_APFloat(X)) ||
+      !match(CI->getArgOperand(1), m_APFloat(Y)))
+    return nullptr;
+
+  if (X->isNaN() || Y->isNaN() || X->isInfinity() || Y->isZero())
+    return nullptr;
----------------
arsenm wrote:

Well, it could/should if we had a generic raise FP except mechanism but we don't. We do not care about fp exceptions, except in strictfp, and only for calls that aren't fpexcept.ignore. So you should still fold this unless the call is strictfp 

https://github.com/llvm/llvm-project/pull/99647