Make test a bit more precise.

llvm-svn: 79073
diff --git a/clang/test/CodeGen/union-init2.c b/clang/test/CodeGen/union-init2.c
index b167f80..184d75f 100644
--- a/clang/test/CodeGen/union-init2.c
+++ b/clang/test/CodeGen/union-init2.c
@@ -1,4 +1,4 @@
-// RUN: clang-cc -emit-llvm %s -o - | not grep ptrtoint
+// RUN: clang-cc -emit-llvm %s -o - -triple i686-pc-linux-gnu | grep "bitcast (%0\* @r to %union.x\*), \[4 x i8\] zeroinitializer"
 
 // Make sure we generate something sane instead of a ptrtoint
 union x {long long b;union x* a;} r = {.a = &r};