Fix caller-save.c:add_used_regs_1 handling of pseudos

[Richard Sandiford]

I noticed in passing that this 4.7 cleanup:

  http://article.gmane.org/gmane.comp.gcc.patches/224853

changed caller-save.c:add_used_regs_1 from:

  if (REG_P (x))
    {
      regno = REGNO (x);
      if (!HARD_REGISTER_NUM_P (regno))
        regno = reg_renumber[regno];
      if (regno >= 0)
        for (i = hard_regno_nregs[regno][GET_MODE (x)] - 1; i >= 0; i--)
          SET_REGNO_REG_SET (live, regno + i);
    }
  return 0;

to:

  if (REG_P (x))
    {
      regno = REGNO (x);
      if (HARD_REGISTER_NUM_P (regno))
        bitmap_set_range (live, regno, hard_regno_nregs[regno][GET_MODE (x)]);
      else
        regno = reg_renumber[regno];
    }
  return 0;

so that nothing happens for pseudos.  I've no idea whether this makes
a difference in practice or not but it seems safer to restore the old
behaviour.

Tested on mipsisa64-sde-elf rather than x86_64-linux-gnu since it only
affects reload targets.  OK to install?

Thanks,
Richard


gcc/
        * caller-save.c (add_used_regs_1): Fix handling of pseudos.

Index: gcc/caller-save.c
===================================================================
--- gcc/caller-save.c   2014-01-02 22:16:03.383281697 +0000
+++ gcc/caller-save.c   2014-02-23 11:04:27.519785327 +0000
@@ -1339,7 +1339,7 @@ insert_save (struct insn_chain *chain, i
 static int
 add_used_regs_1 (rtx *loc, void *data)
 {
-  unsigned int regno;
+  int regno;
   regset live;
   rtx x;
 
@@ -1348,10 +1348,10 @@ add_used_regs_1 (rtx *loc, void *data)
   if (REG_P (x))
     {
       regno = REGNO (x);
-      if (HARD_REGISTER_NUM_P (regno))
-       bitmap_set_range (live, regno, hard_regno_nregs[regno][GET_MODE (x)]);
-      else
+      if (!HARD_REGISTER_NUM_P (regno))
        regno = reg_renumber[regno];
+      if (regno >= 0)
+       bitmap_set_range (live, regno, hard_regno_nregs[regno][GET_MODE (x)]);
     }
   return 0;
 }