re PR rtl-optimization/57708 (function clobbers callee saved register on ARM)

	PR rtl-optimization/57708
	* recog.c (peep2_find_free_register): Validate all regs in a
	multi-reg mode.

From-SVN: r201501

gcc/ChangeLog

+2013-08-05  Richard Earnshaw  <rearnsha@arm.com>
+
+	PR rtl-optimization/57708
+	* recog.c (peep2_find_free_register): Validate all regs in a
+	multi-reg mode.
+
 2013-08-05  Jan Hubicka  <jh@suse.cz>
 
 	PR lto/57602

gcc/recog.c

@@ -3124,32 +3124,53 @@ peep2_find_free_register (int from, int to, const char *class_str,
       regno = raw_regno;
 #endif
 
-      /* Don't allocate fixed registers.  */
-      if (fixed_regs[regno])
-	continue;
-      /* Don't allocate global registers.  */
-      if (global_regs[regno])
-	continue;
-      /* Make sure the register is of the right class.  */
-      if (! TEST_HARD_REG_BIT (reg_class_contents[cl], regno))
-	continue;
-      /* And can support the mode we need.  */
+      /* Can it support the mode we need?  */
       if (! HARD_REGNO_MODE_OK (regno, mode))
 	continue;
-      /* And that we don't create an extra save/restore.  */
-      if (! call_used_regs[regno] && ! df_regs_ever_live_p (regno))
-	continue;
-      if (! targetm.hard_regno_scratch_ok (regno))
-	continue;
-
-      /* And we don't clobber traceback for noreturn functions.  */
-      if ((regno == FRAME_POINTER_REGNUM || regno == HARD_FRAME_POINTER_REGNUM)
-	  && (! reload_completed || frame_pointer_needed))
-	continue;
 
       success = 1;
-      for (j = hard_regno_nregs[regno][mode] - 1; j >= 0; j--)
+      for (j = 0; success && j < hard_regno_nregs[regno][mode]; j++)
 	{
+	  /* Don't allocate fixed registers.  */
+	  if (fixed_regs[regno + j])
+	    {
+	      success = 0;
+	      break;
+	    }
+	  /* Don't allocate global registers.  */
+	  if (global_regs[regno + j])
+	    {
+	      success = 0;
+	      break;
+	    }
+	  /* Make sure the register is of the right class.  */
+	  if (! TEST_HARD_REG_BIT (reg_class_contents[cl], regno + j))
+	    {
+	      success = 0;
+	      break;
+	    }
+	  /* And that we don't create an extra save/restore.  */
+	  if (! call_used_regs[regno + j] && ! df_regs_ever_live_p (regno + j))
+	    {
+	      success = 0;
+	      break;
+	    }
+
+	  if (! targetm.hard_regno_scratch_ok (regno + j))
+	    {
+	      success = 0;
+	      break;
+	    }
+
+	  /* And we don't clobber traceback for noreturn functions.  */
+	  if ((regno + j == FRAME_POINTER_REGNUM
+	       || regno + j == HARD_FRAME_POINTER_REGNUM)
+	      && (! reload_completed || frame_pointer_needed))
+	    {
+	      success = 0;
+	      break;
+	    }
+
 	  if (TEST_HARD_REG_BIT (*reg_set, regno + j)
 	      || TEST_HARD_REG_BIT (live, regno + j))
 	    {
@@ -3157,6 +3178,7 @@ peep2_find_free_register (int from, int to, const char *class_str,
 	      break;
 	    }
 	}
+
       if (success)
 	{
 	  add_to_hard_reg_set (reg_set, mode, regno);