[clang] [Clang][Sema][NFCI] Simplify `resolveAllocationOverload()` (PR #203824)

[Igor Kudrin via cfe-commits]

================
@@ -3006,30 +2922,37 @@ bool Sema::FindAllocationFunctions(
   TypeAwareAllocationMode OriginalTypeAwareState = IAP.PassTypeIdentity;
 
   CXXScalarValueInitExpr TypeIdentityParam(TypeIdentity, nullptr, StartLoc);
-  if (isTypeAwareAllocation(IAP.PassTypeIdentity))
-    AllocArgs.push_back(&TypeIdentityParam);
 
   QualType SizeTy = Context.getSizeType();
   unsigned SizeTyWidth = Context.getTypeSize(SizeTy);
   IntegerLiteral Size(Context, llvm::APInt::getZero(SizeTyWidth), SizeTy,
                       SourceLocation());
-  AllocArgs.push_back(&Size);
 
   QualType AlignValT = Context.VoidTy;
-  bool IncludeAlignParam = isAlignedAllocation(IAP.PassAlignment) ||
-                           isTypeAwareAllocation(IAP.PassTypeIdentity);
-  if (IncludeAlignParam) {
+  if (isTypeAwareAllocation(OriginalTypeAwareState) ||
+      isAlignedAllocation(IAP.PassAlignment)) {
     DeclareGlobalNewDelete();
     AlignValT = Context.getCanonicalTagType(getStdAlignValT());
   }
   CXXScalarValueInitExpr Align(AlignValT, nullptr, SourceLocation());
-  if (IncludeAlignParam)
-    AllocArgs.push_back(&Align);
 
-  llvm::append_range(AllocArgs, PlaceArgs);
+  using ArgsVector = SmallVector<Expr *, 8>;
+  auto FillAllocArgs = [&](TypeAwareAllocationMode TAAM,
+                           AlignedAllocationMode AAM) {
+    ArgsVector AllocArgs;
+    AllocArgs.reserve(IAP.getNumImplicitArgs() + PlaceArgs.size());
+    if (isTypeAwareAllocation(TAAM))
+      AllocArgs.push_back(&TypeIdentityParam);
+    AllocArgs.push_back(&Size);
+    if (isAlignedAllocation(AAM))
+      AllocArgs.push_back(&Align);
+    llvm::append_range(AllocArgs, PlaceArgs);
+    return AllocArgs;
+  };
----------------
igorkudrin wrote:

This suggestion ignores existing nuances, such as the msvc-specific fallback and producing the combined diagnostic for some of the candidate argument lists. The ideas are a good goal for future changes, but they are not minimal NFC changes required to implement CWG2282.

https://github.com/llvm/llvm-project/pull/203824