[llvm] [SVE] Don't require lookup when demangling vector function mappings (PR #72260)

[Maciej Gabka via llvm-commits]

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@@ -273,49 +275,88 @@ ParseRet tryParseAlign(StringRef &ParseString, Align &Alignment) {
   return ParseRet::None;
 }
 
-#ifndef NDEBUG
-// Verify the assumtion that all vectors in the signature of a vector
-// function have the same number of elements.
-bool verifyAllVectorsHaveSameWidth(FunctionType *Signature) {
-  SmallVector<VectorType *, 2> VecTys;
-  if (auto *RetTy = dyn_cast<VectorType>(Signature->getReturnType()))
-    VecTys.push_back(RetTy);
-  for (auto *Ty : Signature->params())
-    if (auto *VTy = dyn_cast<VectorType>(Ty))
-      VecTys.push_back(VTy);
-
-  if (VecTys.size() <= 1)
-    return true;
-
-  assert(VecTys.size() > 1 && "Invalid number of elements.");
-  const ElementCount EC = VecTys[0]->getElementCount();
-  return llvm::all_of(llvm::drop_begin(VecTys), [&EC](VectorType *VTy) {
-    return (EC == VTy->getElementCount());
-  });
+// Given a type, return the size in bits if it is a supported element type
+// for vectorized function calls, or nullopt if not.
+std::optional<unsigned> getSizeFromScalarType(Type *Ty) {
+  // The scalar function should only take scalar arguments.
+  if (!Ty->isIntegerTy() && !Ty->isFloatingPointTy() && !Ty->isPointerTy())
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mgabka wrote:

could be also worth to check here if Ty is not null, unless the idea is that for nullptr it returns std:nullopt (what I guess is what you are relying on when checking the return type later), then would be good to mention it directly in the comment above.

https://github.com/llvm/llvm-project/pull/72260