From: Eric Biggers <ebiggers3@gmail.com>
Date: Sun, 16 Jul 2017 06:26:33 +0000 (-0700)
Subject: unaligned: use may_alias attribute
X-Git-Tag: v1.12.0~6
X-Git-Url: https://wimlib.net/git/?p=wimlib;a=commitdiff_plain;h=e1e717054ca1ba93bfcafbe5f0ec7de7483c1853

unaligned: use may_alias attribute

gcc7 miscompiles the "undo" mode of translate_if_needed() in
lzms_common.c because the get_unaligned_le16() was incorrectly being
moved before the put_unaligned_le32().  Fix it by marking the special
"unaligned" structs with the may_alias attribute.
---

diff --git a/include/wimlib/unaligned.h b/include/wimlib/unaligned.h
index ead46295..473f5e25 100644
--- a/include/wimlib/unaligned.h
+++ b/include/wimlib/unaligned.h
@@ -28,7 +28,7 @@
 #define DEFINE_UNALIGNED_TYPE(type)				\
 struct type##_unaligned {					\
 	type v;							\
-} _packed_attribute;						\
+} _packed_attribute _may_alias_attribute;			\
 								\
 static forceinline type						\
 load_##type##_unaligned(const void *p)				\