[llvm] Fix scalar overload name constructed by ReplaceWithVeclib.cpp (PR #111095)

[Maciej Gabka via llvm-commits]

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@@ -100,20 +100,39 @@ static void replaceWithTLIFunction(IntrinsicInst *II, VFInfo &Info,
 static bool replaceWithCallToVeclib(const TargetLibraryInfo &TLI,
                                     IntrinsicInst *II) {
   assert(II != nullptr && "Intrinsic cannot be null");
-  // At the moment VFABI assumes the return type is always widened unless it is
-  // a void type.
-  auto *VTy = dyn_cast<VectorType>(II->getType());
-  ElementCount EC(VTy ? VTy->getElementCount() : ElementCount::getFixed(0));
+  Intrinsic::ID IID = II->getIntrinsicID();
+  if (IID == Intrinsic::not_intrinsic)
+    return false;
+
+  // RetIsScalar: Return type is not widened.
+  bool RetIsScalar = isVectorIntrinsicWithScalarOpAtArg(IID, -1);
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mgabka wrote:

I believe that VFABI does not allow such cases so in my opinion such cases should not be handled,  but simply rejected, at the very beginning of this function.

https://github.com/llvm/llvm-project/pull/111095