http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57748
--- Comment #19 from Richard Biener <rguenth at gcc dot gnu.org> ---
Barking up wrong trees. Hacky fix looks like:
Index: gcc/expr.c
===================================================================
--- gcc/expr.c (revision 202043)
+++ gcc/expr.c (working copy)
@@ -4753,6 +4753,9 @@ expand_assignment (tree to, tree from, b
{
enum machine_mode address_mode;
rtx offset_rtx;
+ rtx saved_to_rtx = to_rtx;
+ if (misalignp)
+ to_rtx = mem;
if (!MEM_P (to_rtx))
{
@@ -4785,6 +4788,11 @@ expand_assignment (tree to, tree from, b
to_rtx = offset_address (to_rtx, offset_rtx,
highest_pow2_factor_for_target (to,
offset));
+ if (misalignp)
+ {
+ mem = to_rtx;
+ to_rtx = saved_to_rtx;
+ }
}
/* No action is needed if the target is not a memory and the field
volatile bitfield case to be audited as well:
/* If the bitfield is volatile, we want to access it in the
field's mode, not the computed mode.
If a MEM has VOIDmode (external with incomplete type),
use BLKmode for it instead. */
if (MEM_P (to_rtx))
{
if (volatilep && flag_strict_volatile_bitfields > 0)
to_rtx = adjust_address (to_rtx, mode1, 0);
else if (GET_MODE (to_rtx) == VOIDmode)
to_rtx = adjust_address (to_rtx, BLKmode, 0);
}
checks the wrong RTX if it got the movmisalign path. Or rather,
-fstrict-volatile bitfields doesn't seem to work properly for
misaligned accesses?
