gcc-3.4.0 fails for ColdFire(does not satisfy constraints)

[Peter Barada <peter at the-baradas dot com>]

I'm trying to use gcc-3.4.0 --target=m68k-uclinux, and it fails while
trhing to build printf.c from uClibc:

m68k-uclinux-gcc  -Wall -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing  -Os  -Wa,--bitwise-or -I/home/peter/work/src/ucLinux/ucTools/linux-2.4.x/include -m5200   -msoft-float -fno-builtin -nostdinc -D_LIBC -I../../include -I. -I/home/mylocal/uclinux/tools-3.4.0/lib/gcc/m68k-uclinux/3.4.0/include -DNDEBUG -DL__fpmaxtostr printf.c -c -o _fpmaxtostr.o
printf.c: In function `_fpmaxtostr':
printf.c:2454: error: insn does not satisfy its constraints:
(insn 1376 536 537 38 (set (reg:QI 8 %a0)
        (mem:QI (plus:SI (reg/f:SI 14 %a6)
                (const_int -209 [0xffffff2f])) [0 mode+0 S1 A8])) 33 {*m68k.md:826} (nil)
    (nil))
printf.c:2454: internal compiler error: in reload_cse_simplify_operands, at postreload.c:378
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.
make[2]: *** [_fpmaxtostr.o] Error 1
make[2]: Leaving directory `/home/peter/work/src/ucLinux/ucTools/uClibc-0.9.26/libc/stdio'


This problem has been reported before, so I decided to try to fix it
by preventing bytes from being stored in address registers by modifying the
movqi pattern for ColdFire from :

(define_insn ""
  [(set (match_operand:QI 0 "nonimmediate_operand" "=d<Q>,dm,U,d*a")
	(match_operand:QI 1 "general_src_operand" "dmi,d<Q>,U,di*a"))]
  "TARGET_COLDFIRE"
  "* return output_move_qimode (operands);")

to:


(define_insn ""
  [(set (match_operand:QI 0 "nonimmediate_operand" "=d<Q>,dm,U,d")
	(match_operand:QI 1 "general_src_operand" "dmi,d<Q>,U,di"))]
  "TARGET_COLDFIRE"
  "* return output_move_qimode (operands);")


As well as modify HARD_REGNO_MODE_OK from:

#define HARD_REGNO_MODE_OK(REGNO, MODE) \
  (((REGNO) < 16					\
    && !((REGNO) < 8 && (REGNO) + GET_MODE_SIZE (MODE) / 4 > 8))	\
   || ((REGNO) >= 16 && (REGNO) < 24				        \
       && (GET_MODE_CLASS (MODE) == MODE_FLOAT		\
	   || GET_MODE_CLASS (MODE) == MODE_COMPLEX_FLOAT)		\
       && GET_MODE_UNIT_SIZE (MODE) <= 12))


To:

#define HARD_REGNO_MODE_OK(REGNO, MODE) \
  regno_mode_ok(REGNO, MODE)


along with the following code:

/* Value is 1 if hard register REGNO can hold a value of machine-mode MODE.
   On the 68000, the cpu registers can hold any mode except bytes in
   address registers, but the 68881 registers
   can hold only SFmode or DFmode.  */
int regno_mode_ok(int regno, enum machine_mode mode)
{
  if (regno < 8)
    {
      /* Data Registers */
      return 1;
    }
  else if (regno < 16)
    {
      /* Address Registers, can't hold bytes, can hold aggregate if
	 fits in */
      if (GET_MODE_SIZE (mode) == 1)
	return 0;
      if (!((regno) < 8 && (regno) + GET_MODE_SIZE (mode) / 4 > 8))
	return 1;
    }
  else if (regno < 24)
    {
      /* FPU registers, hold float or complex float of long double or smaller */
      if ((GET_MODE_CLASS (mode) == MODE_FLOAT
	   || GET_MODE_CLASS (mode) == MODE_COMPLEX_FLOAT)
	  && GET_MODE_UNIT_SIZE (mode) <= 12)
	return 0;
    }
  return 0;
}


Now fails with:

printf.c: In function `_fpmaxtostr':
printf.c:2454: error: unable to find a register to spill in class `ADDR_REGS'
printf.c:2454: error: this is the insn:
(insn 537 536 538 38 (set (subreg:SI (reg/v:QI 50 [ mode ]) 0)
        (plus:SI (subreg:SI (reg/v:QI 50 [ mode ]) 0)
            (const_int 32 [0x20]))) 90 {*addsi3_5200} (nil)
    (nil))

Breakpoint 1, fancy_abort (
    file=0x82582e0 "/home/peter/work/src/ucLinux/ucTools/gcc-3.4.0/gcc/reload1.c", 
    line=1874, function=0x82580f7 "spill_failure")
    at /home/peter/work/src/ucLinux/ucTools/gcc-3.4.0/gcc/diagnostic.c:584


Any suggestions where I go from here are most appreciated.

-- 
Peter Barada
peter@the-baradas.com