ARM: Correct alignment of structs passed as byval pointer

When a struct has bitfields overlapping with other members
(as required by the AAPCS), clang uses a packed struct to
represent this. If such a struct is large enough for clang to
pass it as a byval pointer (>64 bytes), we need to set the
alignment of the argument to match the original type.

llvm-svn: 203660

1 files changed, 14 insertions, 0 deletions

diff --git a/clang/test/CodeGen/arm-byval-align.c b/clang/test/CodeGen/arm-byval-align.c
new file mode 100644
index 00000000000..aa22503fe4b
--- /dev/null
+++ b/clang/test/CodeGen/arm-byval-align.c
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -triple=armv7-none-eabi < %s -S -emit-llvm | FileCheck %s
+
+struct foo {
+  long long a;
+  char b;
+  int c:16;
+  int d[16];
+};
+
+// CHECK: %struct.foo* byval align 8 %z
+long long bar(int a, int b, int c, int d, int e,
+              struct foo z) {
+  return z.a;
+}