Reapply r95393, without the change to CGExpr. I was wrong in assuming that the
element type always matched the converted LLVM type for ExprType.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@95596 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index f33c2eb..632dcc1 100644
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -703,25 +703,19 @@
   CanQualType CTy = getContext().getCanonicalType(Ty);
 
   llvm::Value *DeclPtr;
-  if (!Ty->isConstantSizeType()) {
-    // Variable sized values always are passed by-reference.
+  // If this is an aggregate or variable sized value, reuse the input pointer.
+  if (!Ty->isConstantSizeType() ||
+      CodeGenFunction::hasAggregateLLVMType(Ty)) {
     DeclPtr = Arg;
   } else {
-    // 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"));
+    // 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);
-    } else {
-      // Otherwise, if this is an aggregate, just use the input pointer.
-      DeclPtr = Arg;
-    }
-    Arg->setName(D.getNameAsString());
+    // Store the initial value into the alloca.
+    EmitStoreOfScalar(Arg, DeclPtr, CTy.isVolatileQualified(), Ty);
   }
+  Arg->setName(D.getName());
 
   llvm::Value *&DMEntry = LocalDeclMap[&D];
   assert(DMEntry == 0 && "Decl already exists in localdeclmap!");
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index d258945..943e890 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -553,6 +553,8 @@
       cast<llvm::PointerType>(Ptr->getType())->getElementType();
 
     // Simple scalar l-value.
+    //
+    // FIXME: We shouldn't have to use isSingleValueType here.
     if (EltTy->isSingleValueType())
       return RValue::get(EmitLoadOfScalar(Ptr, LV.isVolatileQualified(),
                                           ExprType));
diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index 7ea8b08..008a480 100644
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -861,14 +861,13 @@
                                            std::string &ConstraintStr) {
   llvm::Value *Arg;
   if (Info.allowsRegister() || !Info.allowsMemory()) {
-    const llvm::Type *Ty = ConvertType(InputExpr->getType());
-
-    if (Ty->isSingleValueType()) {
+    if (!CodeGenFunction::hasAggregateLLVMType(InputExpr->getType())) {
       Arg = EmitScalarExpr(InputExpr);
     } else {
       InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
       LValue Dest = EmitLValue(InputExpr);
 
+      const llvm::Type *Ty = ConvertType(InputExpr->getType());
       uint64_t Size = CGM.getTargetData().getTypeSizeInBits(Ty);
       if (Size <= 64 && llvm::isPowerOf2_64(Size)) {
         Ty = llvm::IntegerType::get(VMContext, Size);