https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71106
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target| |mips
CC| |ebotcazou at gcc dot gnu.org
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I think that is "expected" behavior for strict-aling targets that do not
provide
a movmisalign handler. But newer GCC (like GCC 6 you used) should behave
correctly here. The issue seems to be that the misalign handling is restricted
to indirect references in expand_assignment.
Thus
Index: gcc/expr.c
===================================================================
--- gcc/expr.c (revision 236309)
+++ gcc/expr.c (working copy)
@@ -4654,9 +4654,7 @@ expand_assignment (tree to, tree from, b
/* Handle misaligned stores. */
mode = TYPE_MODE (TREE_TYPE (to));
- if ((TREE_CODE (to) == MEM_REF
- || TREE_CODE (to) == TARGET_MEM_REF)
- && mode != BLKmode
+ if (mode != BLKmode
&& !mem_ref_refers_to_non_mem_p (to)
&& ((align = get_object_alignment (to))
< GET_MODE_ALIGNMENT (mode))
would fix that. Without pruning some of the "pessimistic" handling in
get_object_alignment this will likely result in some code-gen regressions
though.
Index: gcc/builtins.c
===================================================================
--- gcc/builtins.c (revision 236309)
+++ gcc/builtins.c (working copy)
@@ -339,7 +339,7 @@ get_object_alignment_2 (tree exp, unsign
Do so only if get_pointer_alignment_1 did not reveal absolute
alignment knowledge and if using that alignment would
improve the situation. */
- if (!addr_p && !known_alignment
+ if (!addr_p
&& TYPE_ALIGN (TREE_TYPE (exp)) > align)
align = TYPE_ALIGN (TREE_TYPE (exp));
else
