PR4316: Fix IRGen for cast-to-union extension.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@72803 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 7 insertions, 6 deletions

diff --git a/lib/CodeGen/CGExprAgg.cpp b/lib/CodeGen/CGExprAgg.cpp
index 469c8306b9..8d903d9198 100644
--- a/lib/CodeGen/CGExprAgg.cpp
+++ b/lib/CodeGen/CGExprAgg.cpp
@@ -166,12 +166,12 @@ void AggExprEmitter::EmitFinalDestCopy(const Expr *E, LValue Src, bool Ignore) {
 
 void AggExprEmitter::VisitCStyleCastExpr(CStyleCastExpr *E) {
   // GCC union extension
-  if (E->getType()->isUnionType()) {
-    RecordDecl *SD = E->getType()->getAsRecordType()->getDecl();
-    LValue FieldLoc = CGF.EmitLValueForField(DestPtr, 
-                                             *SD->field_begin(CGF.getContext()),
-                                             true, 0);
-    EmitInitializationToLValue(E->getSubExpr(), FieldLoc);
+  if (E->getSubExpr()->getType()->isScalarType()) {
+    QualType PtrTy =
+        CGF.getContext().getPointerType(E->getSubExpr()->getType());
+    llvm::Value *CastPtr = Builder.CreateBitCast(DestPtr,
+                                                 CGF.ConvertType(PtrTy));
+    EmitInitializationToLValue(E->getSubExpr(), LValue::MakeAddr(CastPtr, 0));
     return;
   }
 
diff --git a/test/CodeGen/cast-to-union.c b/test/CodeGen/cast-to-union.c
index 03aee3e30c..6098bcc5a0 100644
--- a/test/CodeGen/cast-to-union.c
+++ b/test/CodeGen/cast-to-union.c
@@ -7,6 +7,7 @@ union u { int i; double d; };
 
 void foo() {
   union u ola = (union u) 351;
+  union u olb = (union u) 1.0;
 }
 
 union u w = (union u)2;