Merge 97981 from mainline.

add a codegen hack to work around an AST bug, allowing us to compile the
code in PR6537.  This should be reverted when the ast bug is fixed.

llvm-svn: 98298

Author: tlattner

clang/lib/CodeGen/CGExprAgg.cpp

@@ -662,6 +662,16 @@ void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
 
     return;
   }
+  
+  // If we're initializing the whole aggregate, just do it in place.
+  // FIXME: This is a hack around an AST bug (PR6537).
+  if (NumInitElements == 1 && E->getType() == E->getInit(0)->getType()) {
+    EmitInitializationToLValue(E->getInit(0),
+                               LValue::MakeAddr(DestPtr, Qualifiers()),
+                               E->getType());
+    return;
+  }
+  
 
   // Here we iterate over the fields; this makes it simpler to both
   // default-initialize fields and skip over unnamed fields.
@@ -680,8 +690,8 @@ void AggExprEmitter::VisitInitListExpr(InitListExpr *E) {
     // We never generate write-barries for initialized fields.
     LValue::SetObjCNonGC(FieldLoc, true);
     if (CurInitVal < NumInitElements) {
-      // Store the initializer into the field
-      EmitInitializationToLValue(E->getInit(CurInitVal++), FieldLoc, 
+      // Store the initializer into the field.
+      EmitInitializationToLValue(E->getInit(CurInitVal++), FieldLoc,
                                  Field->getType());
     } else {
       // We're out of initalizers; default-initialize to null

clang/test/CodeGen/init.c

@@ -29,3 +29,14 @@ int f4() {
   static const int g4 = 12;
   return g4;
 }
+
+// PR6537
+typedef union vec3 {
+  struct { double x, y, z; };
+  double component[3];
+} vec3;
+vec3 f5(vec3 value) {
+  return (vec3) {{
+    .x = value.x
+  }};
+}