From 43ecd7c71d690a18e655d6c88d6a6333cf750e7f Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk@google.com>
Date: Fri, 20 Nov 2015 17:41:12 +0000
Subject: [PATCH] [DebugInfo] Look through type sugar on union types when
 casting

Fixes PR25584.

llvm-svn: 253680
---
 clang/lib/CodeGen/CGDebugInfo.cpp               |  2 +-
 .../CodeGenCXX/debug-info-anon-union-vars.cpp   | 17 +++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index 582fb7307795..4305280a0c87 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -3329,7 +3329,7 @@ void CGDebugInfo::EmitGlobalVariable(llvm::GlobalVariable *Var,
   // variable for each member of the anonymous union so that it's possible
   // to find the name of any field in the union.
   if (T->isUnionType() && DeclName.empty()) {
-    const RecordDecl *RD = cast<RecordType>(T)->getDecl();
+    const RecordDecl *RD = T->castAs<RecordType>()->getDecl();
     assert(RD->isAnonymousStructOrUnion() &&
            "unnamed non-anonymous struct or union?");
     GV = CollectAnonRecordDecls(RD, Unit, LineNo, LinkageName, Var, DContext);
diff --git a/clang/test/CodeGenCXX/debug-info-anon-union-vars.cpp b/clang/test/CodeGenCXX/debug-info-anon-union-vars.cpp
index 3d3dff7a5ed5..5b0370eb749d 100644
--- a/clang/test/CodeGenCXX/debug-info-anon-union-vars.cpp
+++ b/clang/test/CodeGenCXX/debug-info-anon-union-vars.cpp
@@ -29,11 +29,28 @@ void foo() {
   i = 8;
 }
 
+// A funky reinterpret cast idiom that we used to crash on.
+template <class T>
+unsigned char *buildBytes(const T v) {
+  static union {
+    unsigned char result[sizeof(T)];
+    T value;
+  };
+  value = v;
+  return result;
+}
+
+void instantiate(int x) {
+  buildBytes(x);
+}
+
 // CHECK: [[FILE:.*]] = !DIFile(filename: "{{.*}}debug-info-anon-union-vars.cpp",
 // CHECK: !DIGlobalVariable(name: "c",{{.*}} file: [[FILE]], line: 6,{{.*}} isLocal: true, isDefinition: true
 // CHECK: !DIGlobalVariable(name: "d",{{.*}} file: [[FILE]], line: 6,{{.*}} isLocal: true, isDefinition: true
 // CHECK: !DIGlobalVariable(name: "a",{{.*}} file: [[FILE]], line: 6,{{.*}} isLocal: true, isDefinition: true
 // CHECK: !DIGlobalVariable(name: "b",{{.*}} file: [[FILE]], line: 6,{{.*}} isLocal: true, isDefinition: true
+// CHECK: !DIGlobalVariable(name: "result", {{.*}} isLocal: false, isDefinition: true
+// CHECK: !DIGlobalVariable(name: "value", {{.*}} isLocal: false, isDefinition: true
 // CHECK: !DILocalVariable(name: "i", {{.*}}, flags: DIFlagArtificial
 // CHECK: !DILocalVariable(name: "c", {{.*}}, flags: DIFlagArtificial
 // CHECK: !DILocalVariable(