diff mbox series

[3/9] Remove no_caller_save_reg_set

Message ID mpt1rwo3yi5.fsf@arm.com
State New
Headers show
Series Reduce the amount of global ABI state | expand

Commit Message

Richard Sandiford Sept. 10, 2019, 4:30 p.m. UTC 
Reusing the reasoning from the call_fixed_reg_set patch:

  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    for (j = 1; j <= MOVE_MAX_WORDS; j++)
      if (reg_save_code (i,regno_save_mode[i][j]) == -1)

should be true whenever regno_save_mode[i][j] == VOIDmode,
which it is for:

  ~call_used_reg_set | ~have_save_mode

So this condition amounts to:

  ~call_used_reg_set | ~have_save_mode | ~have_save_insn
  == ~call_used_reg_set | ~savable_regs

no_caller_save_reg_set is then set if call_used_regs[i], so
no_caller_save_reg_set is:

  call_used_reg_set & (~call_used_reg_set | ~savable_regs)
  == call_used_reg_set & ~savable_regs

This patch expands its single user accordingly.

Note that ~savable_regs is always empty on LRA targets.


2019-09-10  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* hard-reg-set.h (target_hard_regs::x_no_caller_save_reg_set): Delete.
	(no_caller_save_reg_set): Delete.
	* caller-save.c (init_caller_save): Don't initialize it.
	* ira-conflicts.c (ira_build_conflicts): Calculate
	no_caller_save_reg_set locally from call_used_reg_set and savable_regs.

Comments

Jeff Law Sept. 10, 2019, 6:30 p.m. UTC | #1 
On 9/10/19 10:30 AM, Richard Sandiford wrote:
> Reusing the reasoning from the call_fixed_reg_set patch:
> 
>   for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
>     for (j = 1; j <= MOVE_MAX_WORDS; j++)
>       if (reg_save_code (i,regno_save_mode[i][j]) == -1)
> 
> should be true whenever regno_save_mode[i][j] == VOIDmode,
> which it is for:
> 
>   ~call_used_reg_set | ~have_save_mode
> 
> So this condition amounts to:
> 
>   ~call_used_reg_set | ~have_save_mode | ~have_save_insn
>   == ~call_used_reg_set | ~savable_regs
> 
> no_caller_save_reg_set is then set if call_used_regs[i], so
> no_caller_save_reg_set is:
> 
>   call_used_reg_set & (~call_used_reg_set | ~savable_regs)
>   == call_used_reg_set & ~savable_regs
> 
> This patch expands its single user accordingly.
> 
> Note that ~savable_regs is always empty on LRA targets.
> 
> 
> 2019-09-10  Richard Sandiford  <richard.sandiford@arm.com>
> 
> gcc/
> 	* hard-reg-set.h (target_hard_regs::x_no_caller_save_reg_set): Delete.
> 	(no_caller_save_reg_set): Delete.
> 	* caller-save.c (init_caller_save): Don't initialize it.
> 	* ira-conflicts.c (ira_build_conflicts): Calculate
> 	no_caller_save_reg_set locally from call_used_reg_set and savable_regs.
OK
jeff
diff mbox series

Patch

Index: gcc/hard-reg-set.h
===================================================================
--- gcc/hard-reg-set.h	2019-09-10 17:22:37.774467353 +0100
+++ gcc/hard-reg-set.h	2019-09-10 17:22:40.938445344 +0100
@@ -424,10 +424,6 @@  struct target_hard_regs {
      with the local stack frame are safe, but scant others.  */
   HARD_REG_SET x_regs_invalidated_by_call;
 
-  /* Call used hard registers which cannot be saved because there is no
-     insn for this.  */
-  HARD_REG_SET x_no_caller_save_reg_set;
-
   /* Table of register numbers in the order in which to try to use them.  */
   int x_reg_alloc_order[FIRST_PSEUDO_REGISTER];
 
@@ -490,8 +486,6 @@  #define savable_regs \
   (this_target_hard_regs->x_savable_regs)
 #define regs_invalidated_by_call \
   (this_target_hard_regs->x_regs_invalidated_by_call)
-#define no_caller_save_reg_set \
-  (this_target_hard_regs->x_no_caller_save_reg_set)
 #define reg_alloc_order \
   (this_target_hard_regs->x_reg_alloc_order)
 #define inv_reg_alloc_order \
Index: gcc/caller-save.c
===================================================================
--- gcc/caller-save.c	2019-09-10 17:22:37.770467379 +0100
+++ gcc/caller-save.c	2019-09-10 17:22:40.938445344 +0100
@@ -192,7 +192,6 @@  init_caller_save (void)
 
   caller_save_initialized_p = true;
 
-  CLEAR_HARD_REG_SET (no_caller_save_reg_set);
   /* First find all the registers that we need to deal with and all
      the modes that they can have.  If we can't find a mode to use,
      we can't have the register live over calls.  */
@@ -264,11 +263,7 @@  init_caller_save (void)
 	{
 	  regno_save_mode[i][j] = VOIDmode;
 	  if (j == 1)
-	    {
-	      CLEAR_HARD_REG_BIT (savable_regs, i);
-	      if (call_used_regs[i])
-		SET_HARD_REG_BIT (no_caller_save_reg_set, i);
-	    }
+	    CLEAR_HARD_REG_BIT (savable_regs, i);
 	}
 }
 
Index: gcc/ira-conflicts.c
===================================================================
--- gcc/ira-conflicts.c	2019-09-09 18:59:20.856063253 +0100
+++ gcc/ira-conflicts.c	2019-09-10 17:22:40.938445344 +0100
@@ -765,6 +765,8 @@  ira_build_conflicts (void)
 	    }
 	  else if (ALLOCNO_CALLS_CROSSED_NUM (a) != 0)
 	    {
+	      HARD_REG_SET no_caller_save_reg_set
+		= (call_used_reg_set & ~savable_regs);
 	      OBJECT_TOTAL_CONFLICT_HARD_REGS (obj) |= no_caller_save_reg_set;
 	      OBJECT_TOTAL_CONFLICT_HARD_REGS (obj) |= temp_hard_reg_set;
 	      OBJECT_CONFLICT_HARD_REGS (obj) |= no_caller_save_reg_set;