Re: stormy16: limit SI reload regs

[Geoff Keating <geoffk at geoffk dot org>]

DJ Delorie <dj@redhat.com> writes:

> One of our internal branches uncovered a failure (not reproducible in
> fsf by coincidence) in divconst-2, whereby $r7 is used as the target
> of an SI move, but that can't be split into two HI moves because $r8
> can't be used that way after the split.  Reload chose $r7 because it's
> in EIGHT_REGS but neglected to see if the mode required registers
> outside that class.  I'm not sure if that's reload's fault or not, but
> I did have success with the attached patch, which creates a sub-class
> just for pre-split SI moves.  Comments?

Yes, this is what you're supposed to do in cases like this.

This patch would be OK if it had a ChangeLog and had been tested (hint
hint :-) ).

> Index: stormy16.c
> ===================================================================
> RCS file: /cvs/gcc/gcc/gcc/config/stormy16/stormy16.c,v
> retrieving revision 1.38
> diff -p -2 -r1.38 stormy16.c
> *** stormy16.c	17 Apr 2003 10:35:08 -0000	1.38
> --- stormy16.c	29 Apr 2003 21:23:17 -0000
> *************** xstormy16_secondary_reload_class (class,
> *** 524,528 ****
>   	       || true_regnum (x) >= FIRST_PSEUDO_REGISTER)))
>         && ! reg_class_subset_p (class, EIGHT_REGS))
> !     return EIGHT_REGS;
>   
>     /* When reloading a PLUS, the carry register will be required
> --- 524,528 ----
>   	       || true_regnum (x) >= FIRST_PSEUDO_REGISTER)))
>         && ! reg_class_subset_p (class, EIGHT_REGS))
> !     return GET_MODE (x) == SImode ? SEVEN_REGS : EIGHT_REGS;
>   
>     /* When reloading a PLUS, the carry register will be required
> *************** xstormy16_preferred_reload_class (x, cla
> *** 576,580 ****
>     if (class == GENERAL_REGS
>         && GET_CODE (x) == MEM)
> !     return EIGHT_REGS;
>   
>     return class;
> --- 576,580 ----
>     if (class == GENERAL_REGS
>         && GET_CODE (x) == MEM)
> !     return GET_MODE (x) == SImode ? SEVEN_REGS : EIGHT_REGS;
>   
>     return class;
> Index: stormy16.h
> ===================================================================
> RCS file: /cvs/gcc/gcc/gcc/config/stormy16/stormy16.h,v
> retrieving revision 1.73
> diff -p -2 -r1.73 stormy16.h
> *** stormy16.h	17 Apr 2003 10:35:08 -0000	1.73
> --- stormy16.h	29 Apr 2003 21:23:17 -0000
> *************** enum reg_class
> *** 405,408 ****
> --- 405,409 ----
>     TWO_REGS,
>     R2_REGS,
> +   SEVEN_REGS,
>     EIGHT_REGS,
>     R8_REGS,
> *************** enum reg_class
> *** 428,431 ****
> --- 429,433 ----
>     "TWO_REGS",					\
>     "R2_REGS",					\
> +   "SEVEN_REGS",					\
>     "EIGHT_REGS",					\
>     "R8_REGS",					\
> *************** enum reg_class
> *** 453,456 ****
> --- 455,459 ----
>     { 0x00003 },					\
>     { 0x00004 },					\
> +   { 0x0007F },					\
>     { 0x000FF },					\
>     { 0x00100 },					\
> *************** enum reg_class
> *** 468,471 ****
> --- 471,475 ----
>      : (REGNO) == 1 ? R1_REGS			\
>      : (REGNO) == 2 ? R2_REGS			\
> +    : (REGNO) < 7  ? SEVEN_REGS			\
>      : (REGNO) < 8  ? EIGHT_REGS			\
>      : (REGNO) == 8 ? R8_REGS			\
> *************** enum reg_class
> *** 506,509 ****
> --- 510,514 ----
>     : (CHAR) == 'c' ? R2_REGS			\
>     : (CHAR) == 'd' ? R8_REGS			\
> +   : (CHAR) == 'f' ? SEVEN_REGS			\
>     : (CHAR) == 'e' ? EIGHT_REGS			\
>     : (CHAR) == 't' ? TWO_REGS			\
> Index: stormy16.md
> ===================================================================
> RCS file: /cvs/gcc/gcc/gcc/config/stormy16/stormy16.md,v
> retrieving revision 1.11
> diff -p -2 -r1.11 stormy16.md
> *** stormy16.md	6 Mar 2003 20:03:49 -0000	1.11
> --- stormy16.md	29 Apr 2003 21:23:17 -0000
> ***************
> *** 1,4 ****
>   ;; XSTORMY16 Machine description template
> ! ;; Copyright (C) 1997, 1998, 1999, 2001, 2002 Free Software Foundation, Inc.
>   ;; Contributed by Red Hat, Inc.
>   
> --- 1,4 ----
>   ;; XSTORMY16 Machine description template
> ! ;; Copyright (C) 1997, 1998, 1999, 2001, 2002, 2003 Free Software Foundation, Inc.
>   ;; Contributed by Red Hat, Inc.
>   
> ***************
> *** 188,193 ****
>   
>   (define_insn_and_split "*movsi_internal"
> !   [(set (match_operand:SI 0 "nonimmediate_operand" "=r,Q,r,m,e,&e,e,r,S")
> ! 	(match_operand:SI 1 "general_operand"       "r,r,R,e,o, V,L,i,i"))]
>     ""
>     "#"
> --- 188,193 ----
>   
>   (define_insn_and_split "*movsi_internal"
> !   [(set (match_operand:SI 0 "nonimmediate_operand" "=r,Q,r,m,f,&f,f,r,S")
> ! 	(match_operand:SI 1 "general_operand"       "r,r,R,f,o, V,L,i,i"))]
>     ""
>     "#"
> 

-- 
- Geoffrey Keating <geoffk@geoffk.org>