From 6c7c575556cbcd49d3fe6321b3bf55c30111b4d9 Mon Sep 17 00:00:00 2001
From: Jameson Nash <vtjnash@gmail.com>
Date: Wed, 1 Apr 2026 14:11:16 -0400
Subject: [PATCH] [clang] fix OutputSemantic list in HLSL (#185550)

Normally sane front-ends with the common calling-conventions avoid
having multiple sret with a return value, so this is NFCI. However,
multiple can be valid. This rewrites an odd looking DenseMap of one
element that was needed for iteration into a more sensible vector.

Noted in https://github.com/llvm/llvm-project/pull/181740 review.
---
 clang/lib/CodeGen/CGHLSLRuntime.cpp | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/clang/lib/CodeGen/CGHLSLRuntime.cpp b/clang/lib/CodeGen/CGHLSLRuntime.cpp
index 4e6f853890c8..6182663111f5 100644
--- a/clang/lib/CodeGen/CGHLSLRuntime.cpp
+++ b/clang/lib/CodeGen/CGHLSLRuntime.cpp
@@ -956,8 +956,7 @@ void CGHLSLRuntime::emitEntryFunction(const FunctionDecl *FD,
     OB.emplace_back("convergencectrl", bundleArgs);
   }
 
-  llvm::DenseMap<const DeclaratorDecl *, std::pair<llvm::Value *, llvm::Type *>>
-      OutputSemantic;
+  SmallVector<std::pair<llvm::Value *, llvm::Type *>> OutputSemantic;
 
   unsigned SRetOffset = 0;
   for (const auto &Param : Fn->args()) {
@@ -965,7 +964,7 @@ void CGHLSLRuntime::emitEntryFunction(const FunctionDecl *FD,
       SRetOffset = 1;
       llvm::Type *VarType = Param.getParamStructRetType();
       llvm::Value *Var = B.CreateAlloca(VarType);
-      OutputSemantic.try_emplace(FD, std::make_pair(Var, VarType));
+      OutputSemantic.push_back(std::make_pair(Var, VarType));
       Args.push_back(Var);
       continue;
     }
@@ -1002,17 +1001,17 @@ void CGHLSLRuntime::emitEntryFunction(const FunctionDecl *FD,
 
   if (Fn->getReturnType() != CGM.VoidTy)
     // Element type is unused, so set to dummy value (NULL).
-    OutputSemantic.try_emplace(FD, std::make_pair(CI, nullptr));
+    OutputSemantic.push_back(std::make_pair(CI, nullptr));
 
-  for (auto &[Decl, SourcePair] : OutputSemantic) {
+  for (auto &SourcePair : OutputSemantic) {
     llvm::Value *Source = SourcePair.first;
     llvm::Type *ElementType = SourcePair.second;
     AllocaInst *AI = dyn_cast<AllocaInst>(Source);
     llvm::Value *SourceValue = AI ? B.CreateLoad(ElementType, Source) : Source;
 
-    auto AttrBegin = Decl->specific_attr_begin<HLSLAppliedSemanticAttr>();
-    auto AttrEnd = Decl->specific_attr_end<HLSLAppliedSemanticAttr>();
-    handleSemanticStore(B, FD, SourceValue, Decl, AttrBegin, AttrEnd);
+    auto AttrBegin = FD->specific_attr_begin<HLSLAppliedSemanticAttr>();
+    auto AttrEnd = FD->specific_attr_end<HLSLAppliedSemanticAttr>();
+    handleSemanticStore(B, FD, SourceValue, FD, AttrBegin, AttrEnd);
   }
 
   B.CreateRetVoid();