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Re: Incorrect code using gcc 2.8.x for Motorola 5200 Coldfire
- To: law at cygnus dot com
- Subject: Re: Incorrect code using gcc 2.8.x for Motorola 5200 Coldfire
- From: John Vickers <jvickers at acorn dot com>
- Date: Tue, 01 Sep 1998 13:10:38 +0100
- CC: Russ Fellows <rfellows at intellistor dot com>, egcs-patches at cygnus dot com
- References: <firstname.lastname@example.org>
Jeffrey A Law wrote:
> In message <35E577BF.D73E3356@intellistor.com>you write:
> > --- m68k.h.orig Tue Aug 11 20:01:02 1998
> > +++ m68k.h Tue Aug 18 06:59:10 1998
> > @@ -468,7 +468,7 @@
> > if 68881 use is disabled. */
> > #define HARD_REGNO_MODE_OK(REGNO, MODE) \
> > - (((REGNO) < 16 \
> > + ((TARGET_5200 && ((REGNO) < 24 && (REGNO) > 7) && (MODE == QImode)) ? 0
> > :
> > ((REGNO) < 16 \
> > && !((REGNO) < 8 && (REGNO) + GET_MODE_SIZE ((MODE)) / 4 > 8)) \
> > || ((REGNO) < 24 \
> > && TARGET_68881 \
> > --- m68k.md.orig Wed Aug 12 02:12:45 1998
> > +++ m68k.md Tue Aug 18 06:58:38 1998
> > @@ -1027,8 +1027,8 @@
> "* return output_move_qimode (operands);")
> > (define_insn ""
> > - [(set (match_operand:QI 0 "general_operand" "=d*a<Q>,d*am")
> > - (match_operand:QI 1 "general_operand" "d*ami,d*a<Q>"))]
> > + [(set (match_operand:QI 0 "general_operand" "=d*<Q>,d*m")
> > + (match_operand:QI 1 "general_operand" "d*mi,d*<Q>"))]
> > "TARGET_5200"
> > "* return output_move_qimode (operands);")
> These seem reasonable if we make them dependent on your target.
> A very quick scan of m68k.md didn't show any other obvious cases where
> we would do a QImode access to an address register.
I missed this last week.
My understanding - which might be quite erroneous - was that QImode
operations were allowed to trash the non-QI
part of the register, so move.l ad,ad and lea i,a could be used
for qimode moves to/from an address reg.
We can't have movstrictqi though.
Preventing QImode values from being in address regs seems a bit severe.
Seems we can allow ri -> a and ri -> d. Movl a0,d0 isn't going to set
On the same basis, perhaps add/subqi3 should be allowed to use address