http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50829
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|rtl-optimization |target
--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> 2011-11-24
03:43:46 UTC ---
The move that is generated in the split should be in the bigger mode. And then
apply the following patch:
* regrename.c (maybe_mode_change): Return the reg in the
new mode if the copy was done in the same mode size.
Index: regrename.c
===================================================================
--- regrename.c (revision 55954)
+++ regrename.c (revision 55955)
@@ -1322,6 +1322,15 @@ maybe_mode_change (enum machine_mode ori
enum machine_mode new_mode, unsigned int regno,
unsigned int copy_regno ATTRIBUTE_UNUSED)
{
+ /* If we are using the register in the copy mode (if the number of hard
+ registers is the same), just used the reg with the new mode. */
+ if (GET_MODE_SIZE (copy_mode) == GET_MODE_SIZE (new_mode)
+ && hard_regno_nregs[copy_regno][copy_mode] ==
+ hard_regno_nregs[copy_regno][new_mode]
+ && hard_regno_nregs[regno][copy_mode] ==
+ hard_regno_nregs[copy_regno][new_mode])
+ return gen_rtx_raw_REG (new_mode, regno);
+
if (GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (orig_mode)
&& GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (new_mode))
return NULL_RTX;
This will at least remove it with -frename-registers which we most likely
should have on by default at -O2 and above now anyways.
