Re: i386-linux cross sh-elf breakage

[Clinton Popetz <cpopetz at cygnus dot com>]

On Thu, May 18, 2000 at 08:49:43PM -0700, Richard Henderson wrote:
> On Tue, May 16, 2000 at 09:27:13PM -0500, Clinton Popetz wrote:
> > #define MODE_USES_IN_EXIT_BLOCK gen_rtx_USE (VOIDmode, get_fpscr_rtx ())
> > 
> > This is used by the other sh mode_switching code, to handle the special
> > case of needing to switch the FP mode back to the default mode for a
> > target ABI.
> 
> This should have been handled with EPILOGUE_USES, I think.

Good point.  I tweaked the mode switching code to deal with the exit block
while it's searching for mode changes, rather than inserting a USE beforehand.

This is orthogonal to the earlier toplev.c patch.   Should I commit both if
c-torture for sh-elf passes?  

				-Clint

Fri May 19 15:23:47 CDT 2000  Clinton Popetz  <cpopetz@cygnus.com>

	* lcm.c (make_preds_opaque): Fix comment.
	(optimize_mode_switching): Use MODE_AT_EXIT instead of 
	MODE_USES_IN_EXIT_BLOCK.  Change leftover instance of
	FP_MODE_NONE to no_mode.
	* tm.texi (OPTIMIZE_MODE_SWITCHING): Refer to MODE_AT_EXIT.
	(MODE_USES_IN_EXIT_BLOCK): Delete.
	(MODE_AT_EXIT) Document.
	* sh.h (MODE_USES_IN_EXIT_BLOCK): Delete.
	(MODE_AT_EXIT): Define.
	(MODE_NEEDED): Don't look for a USE.
	(EPILOGUE_USES): Define.

Index: lcm.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/lcm.c,v
retrieving revision 1.15
diff -c -2 -p -r1.15 lcm.c
*** lcm.c	2000/05/17 21:01:07	1.15
--- lcm.c	2000/05/19 20:21:09
*************** static void make_preds_opaque PARAMS ((b
*** 851,855 ****
  
  /* This function will allocate a new BBINFO structure, initialized
!    with the FP_MODE, INSN, and basic block BB parameters.  */
  
  static struct seginfo *
--- 851,855 ----
  
  /* This function will allocate a new BBINFO structure, initialized
!    with the MODE, INSN, and basic block BB parameters.  */
  
  static struct seginfo *
*************** optimize_mode_switching (file)
*** 995,1021 ****
      return 0;
  
- #ifdef MODE_USES_IN_EXIT_BLOCK
-   /* For some ABIs a particular mode setting is required at function exit.  */
- 
-   for (eg = EXIT_BLOCK_PTR->pred; eg; eg = eg->pred_next)
-     {
-       int bb = eg->src->index;
-       rtx insn = BLOCK_END (bb);
-       rtx use = MODE_USES_IN_EXIT_BLOCK;
- 
-       /* If the block ends with the use of the return value
- 	 and / or a return, insert the new use(s) in front of them.  */
-       while ((GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == USE)
- 	     || GET_CODE (insn) == JUMP_INSN)
- 	insn = PREV_INSN (insn);
- 
-       use = emit_insn_after (use, insn);
-       if (insn == BLOCK_END (bb))
- 	BLOCK_END (bb) = use;
-       else if (NEXT_INSN (use) == BLOCK_HEAD (bb))
- 	BLOCK_HEAD (bb) = NEXT_INSN (insn);
-     }
- #endif /* MODE_USES_IN_EXIT_BLOCK */
- 
    /* Create the bitmap vectors.  */
  
--- 995,998 ----
*************** optimize_mode_switching (file)
*** 1072,1075 ****
--- 1049,1073 ----
  	    }
  
+ 	  /* If this is the last block, and we must force a mode on exit,
+ 	     make note of that.  */
+ #ifdef MODE_AT_EXIT
+ 	  if (bb == (n_basic_blocks - 1) && MODE_AT_EXIT (e) != no_mode 
+ 		  && last_mode != MODE_AT_EXIT (e))
+ 	    {
+ 	      rtx insn = BLOCK_END (bb);
+ 
+ 	      /* Find the last insn before a USE and/or JUMP.  */
+ 	      while ((GET_CODE (insn) == INSN 
+ 	  	      && GET_CODE (PATTERN (insn)) == USE)
+ 		     || GET_CODE (insn) == JUMP_INSN)
+ 		insn = PREV_INSN (insn);
+ 
+ 	      last_mode = MODE_AT_EXIT (e);
+ 	      add_seginfo (info + bb, 
+ 		      new_seginfo (last_mode, insn, bb, live_now));
+ 	      RESET_BIT (transp[bb], j);
+ 	    } 
+ #endif
+ 
  	  info[bb].computing = last_mode;
  	  /* Check for blocks without ANY mode requirements.  */
*************** optimize_mode_switching (file)
*** 1221,1225 ****
  	    {
  	      next = ptr->next;
! 	      if (ptr->mode != FP_MODE_NONE)
  		{
  		  rtx mode_set;
--- 1219,1223 ----
  	    {
  	      next = ptr->next;
! 	      if (ptr->mode != no_mode)
  		{
  		  rtx mode_set;
Index: tm.texi
===================================================================
RCS file: /cvs/gcc/egcs/gcc/tm.texi,v
retrieving revision 1.124
diff -c -2 -p -r1.124 tm.texi
*** tm.texi	2000/05/01 16:53:03	1.124
--- tm.texi	2000/05/19 20:21:16
*************** If you define this macro, you also have 
*** 7275,7279 ****
  @code{NUM_MODES_FOR_MODE_SWITCHING}, @code{MODE_NEEDED},
  @code{MODE_PRIORITY_TO_MODE} and @code{EMIT_MODE_SET}.
! @code{MODE_AT_ENTRY} and @code{MODE_USES_IN_EXIT_BLOCK} are optional.
  
  @findex NUM_MODES_FOR_MODE_SWITCHING
--- 7275,7279 ----
  @code{NUM_MODES_FOR_MODE_SWITCHING}, @code{MODE_NEEDED},
  @code{MODE_PRIORITY_TO_MODE} and @code{EMIT_MODE_SET}.
! @code{MODE_AT_ENTRY} and @code{MODE_AT_EXIT} are optional.
  
  @findex NUM_MODES_FOR_MODE_SWITCHING
*************** represented as numbers 0 .. N - 1.  N is
*** 7290,7302 ****
  switch is needed / supplied.
  
- @findex MODE_USES_IN_EXIT_BLOCK
- @item MODE_USES_IN_EXIT_BLOCK
- If this macro is defined, it is called for each exit block when mode switching
- optimization is performed.  Its return value should be the pattern of an insn,
- or a sequence of insns.  It is emitted before the return insn / use insns at
- the end of the exit block.
- 
- This is done before insns are examined for their need of any mode switching.
- 
  @findex MODE_NEEDED
  @item MODE_NEEDED (@var{entity}, @var{insn})
--- 7290,7293 ----
*************** If this macro is defined, it is evaluate
*** 7312,7315 ****
--- 7303,7312 ----
  mode switching.  It should evaluate to an integer, which is a mode that
  @var{entity} is assumed to be switched to at function entry.
+ 
+ @findex MODE_AT_EXIT
+ @item MODE_AT_EXIT (@var{entity})
+ If this macro is defined, it is evaluated for every @var{entity} that needs
+ mode switching.  It should evaluate to an integer, which is a mode that
+ @var{entity} should have before function exit.
  
  @findex MODE_PRIORITY_TO_MODE
Index: config/sh/sh.h
===================================================================
RCS file: /cvs/gcc/egcs/gcc/config/sh/sh.h,v
retrieving revision 1.61
diff -c -2 -p -r1.61 sh.h
*** sh.h	2000/04/12 20:10:19	1.61
--- sh.h	2000/05/19 20:21:18
*************** do {									\
*** 2250,2261 ****
  #define OPTIMIZE_MODE_SWITCHING(ENTITY) TARGET_SH4
  
! #define MODE_USES_IN_EXIT_BLOCK gen_rtx_USE (VOIDmode, get_fpscr_rtx ())
  
  #define MODE_NEEDED(ENTITY, INSN)					\
    (recog_memoized (INSN) >= 0						\
     ? get_attr_fp_mode (INSN)						\
-    : (GET_CODE (PATTERN (INSN)) == USE				\
-       && rtx_equal_p (XEXP (PATTERN (INSN), 0), get_fpscr_rtx ()))	\
-    ? (TARGET_FPU_SINGLE ? FP_MODE_SINGLE : FP_MODE_DOUBLE)		\
     : FP_MODE_NONE)
  
--- 2250,2261 ----
  #define OPTIMIZE_MODE_SWITCHING(ENTITY) TARGET_SH4
  
! #define MODE_AT_EXIT(ENTITY) \
!    (TARGET_FPU_SINGLE ? FP_MODE_SINGLE : FP_MODE_DOUBLE) 
  
+ #define EPILOGUE_USES(REGNO)       (TARGET_SH4 && (REGNO) == FPSCR_REG)
+ 
  #define MODE_NEEDED(ENTITY, INSN)					\
    (recog_memoized (INSN) >= 0						\
     ? get_attr_fp_mode (INSN)						\
     : FP_MODE_NONE)