don't warn about unused values when the unused value is a statement expression expanded from a macro. This is of dubious utility in general, but is specifically a major issue for the linux kernel. This resolves PR13747.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163034 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 0 deletions

diff --git a/test/Frontend/macros.c b/test/Frontend/macros.c
index 317079709c..828c762840 100644
--- a/test/Frontend/macros.c
+++ b/test/Frontend/macros.c
@@ -2,3 +2,11 @@
 
 int a[(B A) == 1 ? 1 : -1];
 
+
+// PR13747 - Don't warn about unused results with statement exprs in macros.
+void stuff(int,int,int);
+#define memset(x,y,z) ({ stuff(x,y,z); x; })
+
+void foo(int a, int b, int c) {
+  memset(a,b,c);  // No warning!
+}