non-local goto optimization

[Roman Zippel]

Hi,

On Fri, 6 Jul 2007, Eric Botcazou wrote:

> What about renaming calls_unwind_init to saves_all_registers and have the 
> following in reload?
> 
>    if (current_function_has_nonlocal_label && has_nonexceptional_receiver ())
>      current_function_saves_all_registers = 1;
> 
>    if (current_function_saves_all_registers)
>      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
>        if (!call_used_regs[i] && !fixed_regs[i] && !LOCAL_REGNO (i))
>          df_set_regs_ever_live (i, true);

I like that. :)

Retested on i686-linux, cross build of m68k-linux and I checked that all 
register are saved now in unwind-dw2.o.

bye, Roman

200x-xx-xx  Roman Zippel <zippel@linux-m68k.org>

	* function.h (struct function): Rename calls_unwind_init
	to saves_all_register.
	(current_function_saves_all_register): Renamed from
	current_function_calls_unwind_init.
	* reload1.c (reload): Set current_function_saves_all_register.
	* except.c (expand_builtin_unwind_init): Likewise.
	* config/i386/i386.c (ix86_save_reg): Use
	current_function_saves_all_register to save pic register.
	* config/m68k/m68k.c (m68k_save_reg): Likewise.


---
 gcc/config/i386/i386.c |    2 +-
 gcc/config/m68k/m68k.c |    2 +-
 gcc/except.c           |    2 +-
 gcc/function.h         |    9 +++++----
 gcc/reload1.c          |    8 +++++---
 5 files changed, 13 insertions(+), 10 deletions(-)

Index: gcc/gcc/config/i386/i386.c
===================================================================
--- gcc.orig/gcc/config/i386/i386.c
+++ gcc/gcc/config/i386/i386.c
@@ -5604,7 +5604,7 @@ ix86_save_reg (unsigned int regno, int m
       && regno == REAL_PIC_OFFSET_TABLE_REGNUM
       && (df_regs_ever_live_p (REAL_PIC_OFFSET_TABLE_REGNUM)
 	  || current_function_profile
-	  || current_function_calls_eh_return
+	  || current_function_saves_all_register
 	  || current_function_uses_const_pool))
     {
       if (ix86_select_alt_pic_regnum () != INVALID_REGNUM)
Index: gcc/gcc/config/m68k/m68k.c
===================================================================
--- gcc.orig/gcc/config/m68k/m68k.c
+++ gcc/gcc/config/m68k/m68k.c
@@ -769,7 +769,7 @@ m68k_save_reg (unsigned int regno, bool 
     {
       /* A function that receives a nonlocal goto must save all call-saved
 	 registers.  */
-      if (current_function_has_nonlocal_label)
+      if (current_function_saves_all_register)
 	return true;
       if (current_function_uses_pic_offset_table)
 	return true;
Index: gcc/gcc/function.h
===================================================================
--- gcc.orig/gcc/function.h
+++ gcc/gcc/function.h
@@ -408,9 +408,10 @@ struct function GTY(())
      from nested functions.  */
   unsigned int has_nonlocal_label : 1;
 
-  /* Nonzero if function calls builtin_unwind_init.  */
-  unsigned int calls_unwind_init : 1;
-  
+  /* Nonzero if function saves all registers, e.g. if it has a nonlocal
+     label that can reach the exit block via non-exceptional paths. */
+  unsigned int saves_all_register : 1;
+
   /* Nonzero if function being compiled has nonlocal gotos to parent
      function.  */
   unsigned int has_nonlocal_goto : 1;
@@ -515,7 +516,7 @@ extern int trampolines_created;
 #define current_function_uses_const_pool (cfun->uses_const_pool)
 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
-#define current_function_calls_unwind_init (cfun->calls_unwind_init)
+#define current_function_saves_all_register (cfun->saves_all_register)
 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
 
 #define return_label (cfun->x_return_label)
Index: gcc/gcc/reload1.c
===================================================================
--- gcc.orig/gcc/reload1.c
+++ gcc/gcc/reload1.c
@@ -743,9 +743,11 @@ reload (rtx first, int global)
   /* A function that has a nonlocal label that can reach the exit
      block via non-exceptional paths must save all call-saved
      registers.  */
-  if (current_function_calls_unwind_init
-      || (current_function_has_nonlocal_label
-	  && has_nonexceptional_receiver ()))
+  if (current_function_has_nonlocal_label
+      && has_nonexceptional_receiver ())
+    current_function_saves_all_register = 1;
+
+  if (current_function_saves_all_register)
     for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
       if (! call_used_regs[i] && ! fixed_regs[i] && ! LOCAL_REGNO (i))
 	df_set_regs_ever_live (i, true);
Index: gcc/gcc/except.c
===================================================================
--- gcc.orig/gcc/except.c
+++ gcc/gcc/except.c
@@ -2863,7 +2863,7 @@ expand_builtin_unwind_init (void)
 {
   /* Set this so all the registers get saved in our frame; we need to be
      able to copy the saved values for any registers from frames we unwind.  */
-  current_function_calls_unwind_init = 1;
+  current_function_saves_all_register = 1;
 
 #ifdef SETUP_FRAME_ADDRESSES
   SETUP_FRAME_ADDRESSES ();