Use arrays as union padding. Also, since the resulting struct will always contain a single element and either a single i8 element or an array of i8s, there's no reason to use a packed struct.
llvm-svn: 76854
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 4f1f58f..43284b5 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -243,15 +243,18 @@
Types.push_back(C->getType());
unsigned CurSize = CGM.getTargetData().getTypeAllocSize(C->getType());
unsigned TotalSize = CGM.getTargetData().getTypeAllocSize(Ty);
- while (CurSize < TotalSize) {
- Elts.push_back(VMContext.getNullValue(llvm::Type::Int8Ty));
- Types.push_back(llvm::Type::Int8Ty);
- CurSize++;
+
+ assert(CurSize <= TotalSize && "Union size mismatch!");
+ if (unsigned NumPadBytes = TotalSize - CurSize) {
+ const llvm::Type *Ty = llvm::Type::Int8Ty;
+ if (NumPadBytes > 1)
+ Ty = VMContext.getArrayType(Ty, NumPadBytes);
+
+ Elts.push_back(VMContext.getNullValue(Ty));
+ Types.push_back(Ty);
}
- // This always generates a packed struct
- // FIXME: Try to generate an unpacked struct when we can
- llvm::StructType* STy = VMContext.getStructType(Types, true);
+ llvm::StructType* STy = VMContext.getStructType(Types, false);
return VMContext.getConstantStruct(STy, Elts);
}