Remove global call sets: postreload.c

The "|= fixed_regs" in reload_combine isn't necessary, since the
set is only used to determine which values have changed (rather than,
for example, which registers are available for use).

In reload_cse_move2add we can be accurate about which registers
are still available.  BLKmode indicates a continuation of the
previous register, and since clobbers_reg_p handles multi-register
values, it's enough to skip over BLKmode entries and just test the
start register.

2019-09-30  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* postreload.c (reload_combine_recognize_pattern): Use crtl->abi
	when deciding whether a register is free for use after RA.
	(reload_combine): Remove unnecessary use of fixed_reg_set.
	(reload_cse_move2add): Use insn_callee_abi to get the ABI of the
	call insn target.  Use reg_mode when testing whether a register
	is no longer available.

From-SVN: r276328

gcc/ChangeLog

 2019-09-30  Richard Sandiford  <richard.sandiford@arm.com>
 
+	* postreload.c (reload_combine_recognize_pattern): Use crtl->abi
+	when deciding whether a register is free for use after RA.
+	(reload_combine): Remove unnecessary use of fixed_reg_set.
+	(reload_cse_move2add): Use insn_callee_abi to get the ABI of the
+	call insn target.  Use reg_mode when testing whether a register
+	is no longer available.
+
+2019-09-30  Richard Sandiford  <richard.sandiford@arm.com>
+
 	* target.def (return_call_with_max_clobbers): Delete.
 	* doc/tm.texi.in (TARGET_RETURN_CALL_WITH_MAX_CLOBBERS): Delete.
 	* doc/tm.texi: Regenerate.

gcc/postreload.c

@@ -1136,7 +1136,8 @@ reload_combine_recognize_pattern (rtx_insn *insn)
 	      if (TEST_HARD_REG_BIT (reg_class_contents[INDEX_REG_CLASS], i)
 		  && reg_state[i].use_index == RELOAD_COMBINE_MAX_USES
 		  && reg_state[i].store_ruid <= reg_state[regno].use_ruid
-		  && (call_used_or_fixed_reg_p (i) || df_regs_ever_live_p (i))
+		  && (crtl->abi->clobbers_full_reg_p (i)
+		      || df_regs_ever_live_p (i))
 		  && (!frame_pointer_needed || i != HARD_FRAME_POINTER_REGNUM)
 		  && !fixed_regs[i] && !global_regs[i]
 		  && hard_regno_nregs (i, GET_MODE (reg)) == 1
@@ -1332,9 +1333,6 @@ reload_combine (void)
 	{
 	  rtx link;
 	  HARD_REG_SET used_regs = insn_callee_abi (insn).full_reg_clobbers ();
-	  /* ??? This preserves traditional behavior; it might not be
-	     needed.  */
-	  used_regs |= fixed_reg_set;
 
 	  for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
 	    if (TEST_HARD_REG_BIT (used_regs, r))
@@ -2126,12 +2124,13 @@ reload_cse_move2add (rtx_insn *first)
 	 unknown values.  */
       if (CALL_P (insn))
 	{
+	  function_abi callee_abi = insn_callee_abi (insn);
 	  for (i = FIRST_PSEUDO_REGISTER - 1; i >= 0; i--)
-	    {
-	      if (call_used_or_fixed_reg_p (i))
-		/* Reset the information about this register.  */
-		reg_mode[i] = VOIDmode;
-	    }
+	    if (reg_mode[i] != VOIDmode
+		&& reg_mode[i] != BLKmode
+		&& callee_abi.clobbers_reg_p (reg_mode[i], i))
+	      /* Reset the information about this register.  */
+	      reg_mode[i] = VOIDmode;
 	}
     }
   return changed;