Re: i386.md: fp_jcc_3 and TARGET_CMOVE

[Clinton Popetz <cpopetz at cygnus dot com>]

On Thu, Jun 01, 2000 at 03:03:31AM -0700, Richard Henderson wrote:
> On Wed, May 31, 2000 at 12:18:27PM -0500, Clinton Popetz wrote:
> > 	* config/i386/i386.c (ix86_use_fcomi_compare): Make global.
> > 	* config/i386/i386-protos.h (ix86_use_fcomi_compare): Declare.
> > 	* config/i386/i386.md (*fp_jcc_3): Require the second operand
> > 	to be a REG if we can use FCOMI.
> 
> I'm guessing we moved from matching fp_jcc_1 to fp_jcc_3
> during combine, because it thought merging with the memory
> load would be a good idea.

Yes.

> This won't work, I don't believe.  Mostly because
> 
> > !    && (GET_CODE (operands[2]) == REG ||
> > !        !ix86_use_fcomi_compare (GET_CODE (operands[0])))"
> 
> this doesn't get rid of the "m" alternative during reload.  

I hadn't considered that.  
 
> Instead, just add the later half of the clause to disable 
> fp_jcc_[34] if we're planning on using fcomi. 

Thanks.  I committed the appended patch.

			-Clint


Thu Jun  1 09:37:35 2000  Clinton Popetz  <cpopetz@cygnus.com>

	* config/i386/i386.c (ix86_use_fcomi_compare): Make global.
	* config/i386/i386-protos.h (ix86_use_fcomi_compare): Declare.
	* config/i386/i386.md (*fp_jcc_3, *fp_jcc_4): Disable if we
	will use FCOMI.

Index: i386-protos.h
===================================================================
RCS file: /cvs/gcc/egcs/gcc/config/i386/i386-protos.h,v
retrieving revision 1.19
diff -c -2 -p -r1.19 i386-protos.h
*** i386-protos.h	2000/04/27 14:56:46	1.19
--- i386-protos.h	2000/06/01 14:35:18
*************** extern int ix86_unary_operator_ok PARAMS
*** 100,103 ****
--- 100,104 ----
  extern int ix86_match_ccmode PARAMS ((rtx, enum machine_mode));
  extern rtx ix86_expand_fp_compare PARAMS ((enum rtx_code, rtx, rtx, rtx));
+ extern int ix86_use_fcomi_compare PARAMS ((enum rtx_code));
  extern void ix86_expand_branch PARAMS ((enum rtx_code, rtx));
  extern int ix86_expand_setcc PARAMS ((enum rtx_code, rtx));
Index: i386.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/config/i386/i386.c,v
retrieving revision 1.159
diff -c -2 -p -r1.159 i386.c
*** i386.c	2000/04/27 14:56:46	1.159
--- i386.c	2000/06/01 14:35:29
*************** static enum rtx_code unsigned_comparison
*** 393,397 ****
  static rtx ix86_expand_int_compare PARAMS ((enum rtx_code, rtx, rtx));
  static enum machine_mode ix86_fp_compare_mode PARAMS ((enum rtx_code));
- static int ix86_use_fcomi_compare PARAMS ((enum rtx_code));
  static enum rtx_code ix86_prepare_fp_compare_args PARAMS ((enum rtx_code,
  							   rtx *, rtx *));
--- 393,396 ----
*************** ix86_fp_compare_mode (code)
*** 4540,4544 ****
  /* Return true if we should use an FCOMI instruction for this fp comparison.  */
  
! static int
  ix86_use_fcomi_compare (code)
       enum rtx_code code;
--- 4539,4543 ----
  /* Return true if we should use an FCOMI instruction for this fp comparison.  */
  
! int
  ix86_use_fcomi_compare (code)
       enum rtx_code code;
Index: i386.md
===================================================================
RCS file: /cvs/gcc/egcs/gcc/config/i386/i386.md,v
retrieving revision 1.156
diff -c -2 -p -r1.156 i386.md
*** i386.md	2000/05/27 20:23:15	1.156
--- i386.md	2000/06/01 14:35:48
***************
*** 7154,7158 ****
    "TARGET_80387
     && (GET_MODE (operands[1]) == SFmode || GET_MODE (operands[1]) == DFmode)
!    && GET_MODE (operands[1]) == GET_MODE (operands[2])"
    "#")
  
--- 7154,7159 ----
    "TARGET_80387
     && (GET_MODE (operands[1]) == SFmode || GET_MODE (operands[1]) == DFmode)
!    && GET_MODE (operands[1]) == GET_MODE (operands[2])
!    && !ix86_use_fcomi_compare (GET_CODE (operands[0]))"
    "#")
  
***************
*** 7169,7173 ****
    "TARGET_80387
     && (GET_MODE (operands[1]) == SFmode || GET_MODE (operands[1]) == DFmode)
!    && GET_MODE (operands[1]) == GET_MODE (operands[2])"
    "#")
  
--- 7170,7175 ----
    "TARGET_80387
     && (GET_MODE (operands[1]) == SFmode || GET_MODE (operands[1]) == DFmode)
!    && GET_MODE (operands[1]) == GET_MODE (operands[2])
!    && !ix86_use_fcomi_compare (GET_CODE (operands[0]))"
    "#")