commit 892bb0cace9f733df800e4875fcf9325f860501a
author Reid Kleckner <reid@kleckner.net> Wed May 20 21:59:25 2015 +0000
committer Reid Kleckner <reid@kleckner.net> Wed May 20 21:59:25 2015 +0000
tree beec6f4d8624b513239270980ae51f497f6e2a40
parent 0c28fd7fda3d9e58d9efefb63a249e0270ef7ba4

Evaluate union cast subexpressions when the cast value is unused

Fixes PR23597.

llvm-svn: 237839

clang/lib/CodeGen/CGExprAgg.cpp

diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 77e4464e..6fedf0e 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -584,7 +584,12 @@
   }
       
   case CK_ToUnion: {
-    if (Dest.isIgnored()) break;
+    // Evaluate even if the destination is ignored.
+    if (Dest.isIgnored()) {
+      CGF.EmitAnyExpr(E->getSubExpr(), AggValueSlot::ignored(),
+                      /*ignoreResult=*/true);
+      break;
+    }
 
     // GCC union extension
     QualType Ty = E->getSubExpr()->getType();