[PATCH] fix hardreg_cprop to honor HARD_REGNO_MODE_OK.

[Ilya Tocar]

Hi,

I've observed SPEC2006 failure on avx512-vlbwdq branch.
It was caused by  hardreg_cprop. In maybe_mode_change it was
assumed, that all values of the same register class and same mode.
are ok. This is not the case for i386/avx512. We need to honor
HARD_REGNO_MODE_OK.
Patch bellow does it.
Ok for trunk?

2014-08-11  Ilya Tocar  <ilya.to...@intel.com>

        * regcprop.c (maybe_mode_change): Honor HARD_REGNO_MODE_OK.


---
 gcc/regcprop.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/regcprop.c b/gcc/regcprop.c
index 932037d..694deb2 100644
--- a/gcc/regcprop.c
+++ b/gcc/regcprop.c
@@ -410,7 +410,7 @@ maybe_mode_change (enum machine_mode orig_mode, enum 
machine_mode copy_mode,
       && GET_MODE_SIZE (copy_mode) < GET_MODE_SIZE (new_mode))
     return NULL_RTX;
 
-  if (orig_mode == new_mode)
+  if (orig_mode == new_mode && HARD_REGNO_MODE_OK (regno, new_mode))
     return gen_rtx_raw_REG (new_mode, regno);
   else if (mode_change_ok (orig_mode, new_mode, regno))
     {
-- 
1.8.3.1