http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57748
--- Comment #25 from Richard Biener <rguenth at gcc dot gnu.org> ---
I think that
tem = get_inner_reference (to, &bitsize, &bitpos, &offset, &mode1,
&unsignedp, &volatilep, true);
if (TREE_CODE (to) == COMPONENT_REF
&& DECL_BIT_FIELD_TYPE (TREE_OPERAND (to, 1)))
get_bit_range (&bitregion_start, &bitregion_end, to, &bitpos, &offset);
/* If we are going to use store_bit_field and extract_bit_field,
make sure to_rtx will be safe for multiple use. */
mode = TYPE_MODE (TREE_TYPE (tem));
if (TREE_CODE (tem) == MEM_REF
&& mode != BLKmode
&& ((align = get_object_alignment (tem))
< GET_MODE_ALIGNMENT (mode))
&& ((icode = optab_handler (movmisalign_optab, mode))
!= CODE_FOR_nothing))
is overly pessimistic. What matters is the mode of the access, not that
of the access base object!
Which means the pre-handling of
/* Handle misaligned stores. */
mode = TYPE_MODE (TREE_TYPE (to));
if ((TREE_CODE (to) == MEM_REF
|| TREE_CODE (to) == TARGET_MEM_REF)
&& mode != BLKmode
&& !mem_ref_refers_to_non_mem_p (to)
should be made to trigger for all 'to', not just bare MEM_REF/TARGET_MEM_REF.
Then the other movmisalign path can be completely removed.
