Implement codegen for MSVC unions with reference members.

Currently, clang accepts a union with a reference member when given the -fms-extensions flag. This change fixes the codegen for this case.

Patch by Dominic Ferreira.

llvm-svn: 370052

1 files changed, 34 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/ms-union-member-ref.cpp b/clang/test/CodeGenCXX/ms-union-member-ref.cpp
new file mode 100644
index 00000000000..658cfba9378
--- /dev/null
+++ b/clang/test/CodeGenCXX/ms-union-member-ref.cpp
@@ -0,0 +1,34 @@
+// RUN: %clang_cc1 -fms-extensions %s -emit-llvm -o- | FileCheck %s
+
+union A {
+  int *&ref;
+  int **ptr;
+};
+
+int *f1(A *a) {
+  return a->ref;
+}
+// CHECK-LABEL: define {{.*}}i32* @_Z2f1P1A(%union.A* %a)
+// CHECK:       [[REF:%[^[:space:]]+]] = bitcast %union.A* %{{.*}} to i32***
+// CHECK:       [[IPP:%[^[:space:]]+]] = load i32**, i32*** [[REF]]
+// CHECK:       [[IP:%[^[:space:]]+]]  = load i32*, i32** [[IPP]]
+// CHECK:       ret i32* [[IP]]
+
+void f2(A *a) {
+  *a->ref = 1;
+}
+// CHECK-LABEL: define {{.*}}void @_Z2f2P1A(%union.A* %a)
+// CHECK:       [[REF:%[^[:space:]]+]] = bitcast %union.A* %{{.*}} to i32***
+// CHECK:       [[IPP:%[^[:space:]]+]] = load i32**, i32*** [[REF]]
+// CHECK:       [[IP:%[^[:space:]]+]]  = load i32*, i32** [[IPP]]
+// CHECK:       store i32 1, i32* [[IP]]
+
+bool f3(A *a, int *b) {
+  return a->ref != b;
+}
+// CHECK-LABEL: define {{.*}}i1 @_Z2f3P1APi(%union.A* %a, i32* %b)
+// CHECK:       [[REF:%[^[:space:]]+]] = bitcast %union.A* %{{.*}} to i32***
+// CHECK:       [[IPP:%[^[:space:]]+]] = load i32**, i32*** [[REF]]
+// CHECK:       [[IP:%[^[:space:]]+]]  = load i32*, i32** [[IPP]]
+// CHECK:       [[IP2:%[^[:space:]]+]]  = load i32*, i32** %b.addr
+// CHECK:       icmp ne i32* [[IP]], [[IP2]]