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Re: gcc-4.5/4.4: Bug in .subreg1 pass?
Denis Chertykov schrieb:
2011/2/26 Georg-Johann Lay <avr@gjlay.de>:
Ok, this is the patch I meant:
http://gcc.gnu.org/viewcvs?view=revision&revision=86842
it allows just Pmode in r29:r28 because of some spill failures in PR15417
and PR12017.
It was a stupid workaround.
I think that the problem exists anyway because it's not a port problem.
Denis.
PR41894 is yet another variation of the problem.
Removong the restricting code like so
int
avr_hard_regno_mode_ok (int regno, enum machine_mode mode)
{
/* Disallow QImode in stack pointer regs. */
if ((regno == REG_SP || regno == (REG_SP + 1)) && mode == QImode)
return 0;
- /* The only thing that can go into registers r28:r29 is a Pmode. */
- if (regno == REG_Y && mode == Pmode)
- return 1;
-
- /* Otherwise disallow all regno/mode combinations that span r28:r29.
- */
- if (regno <= (REG_Y + 1) && (regno + GET_MODE_SIZE (mode)) >= (REG_Y
+ 1))
- return 0;
-
if (mode == QImode)
return 1;
/* Modes larger than QImode occupy consecutive registers. */
if (regno + GET_MODE_SIZE (mode) > FIRST_PSEUDO_REGISTER)
return 0;
/* All modes larger than QImode should start in an even register. */
return !(regno & 1);
}
leads to correct code.
But I don't understand enough of reload/inerts of fp elimination to
estimate all undesired side effects.
Maybe someone with more insight in reload can comment on this issue?
Johann