Revert r95393, which broke Clang's self-host.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@95430 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 10 deletions

diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index d18b87fb9a..e27c5e4e51 100644
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -690,19 +690,25 @@ void CodeGenFunction::EmitParmDecl(const VarDecl &D, llvm::Value *Arg) {
   CanQualType CTy = getContext().getCanonicalType(Ty);
 
   llvm::Value *DeclPtr;
-  // If this is an aggregate or variable sized value, reuse the input pointer.
-  if (!Ty->isConstantSizeType() ||
-      CodeGenFunction::hasAggregateLLVMType(Ty)) {
+  if (!Ty->isConstantSizeType()) {
+    // Variable sized values always are passed by-reference.
     DeclPtr = Arg;
   } else {
-    // Otherwise, create a temporary to hold the value.
-    DeclPtr = CreateTempAlloca(ConvertTypeForMem(Ty));
-    DeclPtr->setName(D.getName() + ".addr");
-
-    // Store the initial value into the alloca.
-    EmitStoreOfScalar(Arg, DeclPtr, CTy.isVolatileQualified(), Ty);
+    // A fixed sized single-value variable becomes an alloca in the entry block.
+    const llvm::Type *LTy = ConvertTypeForMem(Ty);
+    if (LTy->isSingleValueType()) {
+      // TODO: Alignment
+      DeclPtr = CreateTempAlloca(LTy);
+      DeclPtr->setName(D.getNameAsString() + llvm::StringRef(".addr"));
+
+      // Store the initial value into the alloca.
+      EmitStoreOfScalar(Arg, DeclPtr, CTy.isVolatileQualified(), Ty);
+    } else {
+      // Otherwise, if this is an aggregate, just use the input pointer.
+      DeclPtr = Arg;
+    }
+    Arg->setName(D.getNameAsString());
   }
-  Arg->setName(D.getName());
 
   llvm::Value *&DMEntry = LocalDeclMap[&D];
   assert(DMEntry == 0 && "Decl already exists in localdeclmap!");