PATCH: PR tree-optimization/60024: global-buffer-overflow in init_regs_for_mode

[H.J. Lu]

Hi,

init_regs_for_mode accesses global_regs before checking if regno is OK
for a mode, which leads to buffer overflow.  This patch moves
HARD_REGNO_MODE_OK for checking global_regs.  There is no functional
change.  OK for trunk?

Thanks.


H.J.
---
2014-02-01  H.J. Lu  <hongjiu...@intel.com>

        PR tree-optimization/60024
        * sel-sched.c (init_regs_for_mode): Check if mode is OK first.

diff --git a/gcc/sel-sched.c b/gcc/sel-sched.c
index ad4a0aa..7b1a183 100644
--- a/gcc/sel-sched.c
+++ b/gcc/sel-sched.c
@@ -1116,9 +1116,16 @@ init_regs_for_mode (enum machine_mode mode)
 
   for (cur_reg = 0; cur_reg < FIRST_PSEUDO_REGISTER; cur_reg++)
     {
-      int nregs = hard_regno_nregs[cur_reg][mode];
+      int nregs;
       int i;
 
+      /* See whether it accepts all modes that occur in
+         original insns.  */
+      if (! HARD_REGNO_MODE_OK (cur_reg, mode))
+        continue;
+
+      nregs = hard_regno_nregs[cur_reg][mode];
+
       for (i = nregs - 1; i >= 0; --i)
         if (fixed_regs[cur_reg + i]
                 || global_regs[cur_reg + i]
@@ -1140,11 +1147,6 @@ init_regs_for_mode (enum machine_mode mode)
       if (i >= 0)
         continue;
 
-      /* See whether it accepts all modes that occur in
-         original insns.  */
-      if (! HARD_REGNO_MODE_OK (cur_reg, mode))
-        continue;
-
       if (HARD_REGNO_CALL_PART_CLOBBERED (cur_reg, mode))
         SET_HARD_REG_BIT (sel_hrd.regs_for_call_clobbered[mode],
                           cur_reg);