Patchwork RFA: MN10300: Replace REG_SAVE_BYTES macro with calls to mn10300_get_live_callee_saved_regs

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Submitter Nick Clifton
Date June 29, 2012, 9:03 a.m.
Message ID <87a9zmsd63.fsf@redhat.com>
Download mbox | patch
Permalink /patch/168022/
State New
Headers show

Comments

Nick Clifton - June 29, 2012, 9:03 a.m.
Hi Jeff, Hi Alex,

  I recently encountered a problem with the REG_SAVE_BYTES macro in the
  mn10300 backend.  When compiling some code in -fPID mode it was
  producing a different result to the mask computed by
  mn10300_get_live_callee_saved_regs.  The problem turned out to be that
  the macro was not checking the call_really_saved_regs array.  Rather
  than update the macro, it seemed to me that it would be better to just
  make this computation in one place - the
  mn10300_get_live_callee_saved_regs function - and avoid problems like
  this in the future.

  So attached is a patch that does this.  Tested with no regressions on
  an mn10300-elf and an am33_2.0-linux-gnu toolchain.  OK to apply ?

Cheers
  Nick

gcc/ChangeLog
2012-06-29  Nick Clifton  <nickc@redhat.com>

	* config/mn10300/mn10300.c (REG_SAVE_BYTES): Delete.
	(mn10300_get_live_callee_saved_regs): If requested return a count
	of the number of bytes in the mask.
	(mn10300_expand_prologue): Add argument to invocation of
	mn10300_get_live_callee_regs.
	(mn10300_expand_epilogue): Compute reg_save_bytes by calling
	mn10300_get_live_callee_saved_regs.
	(mn10300_initial_offset): Likewise.
	* config/mn10300/mn10300-protos.h (mn10300_get_live_callee_saved_regs):
	Update prototype.
	* config/mn10300/mn10300.md (return_ret): Add argument to
	invocation of mn10300_get_live_callee_saved_regs.
Richard Henderson - July 25, 2012, 6:43 p.m.
On 06/29/2012 02:03 AM, Nick Clifton wrote:
> 2012-06-29  Nick Clifton  <nickc@redhat.com>
> 
> 	* config/mn10300/mn10300.c (REG_SAVE_BYTES): Delete.
> 	(mn10300_get_live_callee_saved_regs): If requested return a count
> 	of the number of bytes in the mask.
> 	(mn10300_expand_prologue): Add argument to invocation of
> 	mn10300_get_live_callee_regs.
> 	(mn10300_expand_epilogue): Compute reg_save_bytes by calling
> 	mn10300_get_live_callee_saved_regs.
> 	(mn10300_initial_offset): Likewise.
> 	* config/mn10300/mn10300-protos.h (mn10300_get_live_callee_saved_regs):
> 	Update prototype.
> 	* config/mn10300/mn10300.md (return_ret): Add argument to
> 	invocation of mn10300_get_live_callee_saved_regs.


Ok.


r~

Patch

Index: gcc/config/mn10300/mn10300.md
===================================================================
--- gcc/config/mn10300/mn10300.md	(revision 189067)
+++ gcc/config/mn10300/mn10300.md	(working copy)
@@ -2048,7 +2048,7 @@ 
 {
   /* The RETF insn is up to 3 cycles faster than RET.  */
   fputs ((mn10300_can_use_retf_insn () ? "\tretf " : "\tret "), asm_out_file);
-  mn10300_print_reg_list (asm_out_file, mn10300_get_live_callee_saved_regs ());
+  mn10300_print_reg_list (asm_out_file, mn10300_get_live_callee_saved_regs (NULL));
   fprintf (asm_out_file, ",%d\n", (int) INTVAL (operands[0]));
   return "";
 })
Index: gcc/config/mn10300/mn10300-protos.h
===================================================================
--- gcc/config/mn10300/mn10300-protos.h	(revision 189067)
+++ gcc/config/mn10300/mn10300-protos.h	(working copy)
@@ -25,7 +25,7 @@ 
 extern rtx   mn10300_legitimize_reload_address (rtx, enum machine_mode,
 						int, int, int);
 extern bool  mn10300_function_value_regno_p (const unsigned int);
-extern int   mn10300_get_live_callee_saved_regs (void);
+extern unsigned int   mn10300_get_live_callee_saved_regs (unsigned int *);
 extern bool  mn10300_hard_regno_mode_ok (unsigned int, enum machine_mode);
 extern bool  mn10300_modes_tieable (enum machine_mode, enum machine_mode);
 extern const char *mn10300_output_add (rtx[3], bool);
Index: gcc/config/mn10300/mn10300.c
===================================================================
--- gcc/config/mn10300/mn10300.c	(revision 189067)
+++ gcc/config/mn10300/mn10300.c	(working copy)
@@ -56,18 +56,6 @@ 
 /* Selected processor type for tuning.  */
 enum processor_type mn10300_tune_cpu = PROCESSOR_DEFAULT;
 
-/* The size of the callee register save area.  Right now we save everything
-   on entry since it costs us nothing in code size.  It does cost us from a
-   speed standpoint, so we want to optimize this sooner or later.  */
-#define REG_SAVE_BYTES (4 * df_regs_ever_live_p (2)		\
-			+ 4 * df_regs_ever_live_p (3)		\
-		        + 4 * df_regs_ever_live_p (6)		\
-			+ 4 * df_regs_ever_live_p (7)		\
-			+ 16 * (df_regs_ever_live_p (14)	\
-				|| df_regs_ever_live_p (15)	\
-				|| df_regs_ever_live_p (16)	\
-				|| df_regs_ever_live_p (17)))
-
 #define CC_FLAG_Z	1
 #define CC_FLAG_N	2
 #define CC_FLAG_C	4
@@ -634,21 +622,36 @@ 
 
 /* Returns the set of live, callee-saved registers as a bitmask.  The
    callee-saved extended registers cannot be stored individually, so
-   all of them will be included in the mask if any one of them is used.  */
+   Also returns the number of bytes in the registers in the mask if
+   BYTES_SAVED is not NULL.  */
 
-int
-mn10300_get_live_callee_saved_regs (void)
+unsigned int
+mn10300_get_live_callee_saved_regs (unsigned int * bytes_saved)
 {
   int mask;
   int i;
+  unsigned int count;
 
-  mask = 0;
+  count = mask = 0;
   for (i = 0; i <= LAST_EXTENDED_REGNUM; i++)
     if (df_regs_ever_live_p (i) && ! call_really_used_regs[i])
-      mask |= (1 << i);
+      {
+	mask |= (1 << i);
+	++ count;
+      }
+
   if ((mask & 0x3c000) != 0)
-    mask |= 0x3c000;
+    {
+      for (i = 0x04000; i < 0x40000; i <<= 1)
+	if ((mask & i) == 0)
+	  ++ count;
+      
+      mask |= 0x3c000;
+    }
 
+  if (bytes_saved)
+    * bytes_saved = count * UNITS_PER_WORD;
+
   return mask;
 }
 
@@ -741,7 +744,7 @@ 
   HOST_WIDE_INT size = mn10300_frame_size ();
 
   /* If we use any of the callee-saved registers, save them now.  */
-  mn10300_gen_multiple_store (mn10300_get_live_callee_saved_regs ());
+  mn10300_gen_multiple_store (mn10300_get_live_callee_saved_regs (NULL));
 
   if (TARGET_AM33_2 && fp_regs_to_save ())
     {
@@ -998,8 +1001,10 @@ 
 mn10300_expand_epilogue (void)
 {
   HOST_WIDE_INT size = mn10300_frame_size ();
-  int reg_save_bytes = REG_SAVE_BYTES;
-  
+  unsigned int reg_save_bytes;
+
+  mn10300_get_live_callee_saved_regs (& reg_save_bytes);
+
   if (TARGET_AM33_2 && fp_regs_to_save ())
     {
       int num_regs_to_save = fp_regs_to_save (), i;
@@ -1219,7 +1224,7 @@ 
   if (mn10300_can_use_rets_insn ())
     emit_jump_insn (ret_rtx);
   else
-    emit_jump_insn (gen_return_ret (GEN_INT (size + REG_SAVE_BYTES)));
+    emit_jump_insn (gen_return_ret (GEN_INT (size + reg_save_bytes)));
 }
 
 /* Recognize the PARALLEL rtx generated by mn10300_gen_multiple_store().
@@ -1434,7 +1439,10 @@ 
      is the size of the callee register save area.  */
   if (from == ARG_POINTER_REGNUM)
     {
-      diff += REG_SAVE_BYTES;
+      unsigned int reg_save_bytes;
+
+      mn10300_get_live_callee_saved_regs (& reg_save_bytes);
+      diff += reg_save_bytes;
       diff += 4 * fp_regs_to_save ();
     }