The following patch enables bswap-from-load for STRICT_ALIGNMENT
targets when the load is aligned instead of unconditionally
(which probably was not intended).
(note to self: we should fully transition to use SLOW_UNALIGNED_ACCESS)
Bootstrapped and tested on x86_64-unknown-linux-gnu.
Richard.
2014-06-27 Richard Biener <rguent...@suse.de>
* tree-ssa-math-opts.c (bswap_replace): Fix
SLOW_UNALIGNED_ACCESS test to only apply to unaligned object.
Index: gcc/tree-ssa-math-opts.c
===================================================================
--- gcc/tree-ssa-math-opts.c (revision 212064)
+++ gcc/tree-ssa-math-opts.c (working copy)
@@ -2179,7 +2179,9 @@ bswap_replace (gimple cur_stmt, gimple_s
unsigned align;
align = get_object_alignment (src);
- if (bswap && SLOW_UNALIGNED_ACCESS (TYPE_MODE (load_type), align))
+ if (bswap
+ && align < GET_MODE_ALIGNMENT (TYPE_MODE (load_type))
+ && SLOW_UNALIGNED_ACCESS (TYPE_MODE (load_type), align))
return false;
gsi_move_before (&gsi, &gsi_ins);
