http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51134
--- Comment #4 from Jan Hubicka <hubicka at ucw dot cz> 2011-11-15 13:28:42 UTC
---
Hi,
the bug is loopy epilogue not being used because promoted value is not
availbale. The non-loopy epilogue does not expect alignments
greater than 16.
I am testing the following patch.
I think we might still have bugs for blocks >8 && <16. Will try to produce
testcase.
Honza
Index: config/i386/i386.c
===================================================================
--- config/i386/i386.c (revision 181357)
+++ config/i386/i386.c (working copy)
@@ -23073,13 +23073,13 @@ ix86_expand_setmem (rtx dst, rtx count_e
rtx tmp;
if (align_unknown && unroll_factor > 1
&& epilogue_size_needed >= GET_MODE_SIZE (move_mode)
- && vec_promoted_val)
+ && (vec_promoted_val || gpr_promoted_val))
{
/* Reduce epilogue's size by creating not-unrolled loop. If we won't
do this, we can have very big epilogue - when alignment is statically
unknown we'll have the epilogue byte by byte which may be very slow.
*/
loop_iter = expand_set_or_movmem_via_loop_with_iter (dst, NULL, destreg,
- NULL, vec_promoted_val, count_exp,
+ NULL, vec_promoted_val ? vec_promoted_val : gpr_promoted_val,
count_exp,
loop_iter, move_mode, 1,
expected_size, false);
dst = change_address (dst, BLKmode, destreg);
