[Sema] Teach -Wcast-align to look at the aligned attribute of the

declared variables.

Teach Sema to check the aligned attribute attached to variable
declarations so that it doesn't issue spurious warnings.

rdar://problem/26517471

Differential revision: https://reviews.llvm.org/D21099

llvm-svn: 288267

1 files changed, 20 insertions, 0 deletions

diff --git a/clang/test/Sema/warn-cast-align.c b/clang/test/Sema/warn-cast-align.c
index 9d64699bb5b..e8f85bc14d8 100644
--- a/clang/test/Sema/warn-cast-align.c
+++ b/clang/test/Sema/warn-cast-align.c
@@ -39,3 +39,23 @@ void test2(char *P) {
 void test3(char *P) {
   struct B *b = (struct B*) P;
 }
+
+// Do not issue a warning. The aligned attribute changes the alignment of the
+// variables and fields.
+char __attribute__((aligned(4))) a[16];
+
+struct S0 {
+  char a[16];
+};
+
+struct S {
+  char __attribute__((aligned(4))) a[16];
+  struct S0 __attribute__((aligned(4))) s0;
+};
+
+void test4() {
+  struct S s;
+  int *i = (int *)s.a;
+  i = (int *)&s.s0;
+  i = (int *)a;
+}