http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56195
Vladimir Makarov <vmakarov at redhat dot com> changed:
What |Removed |Added
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CC| |vmakarov at redhat dot com
--- Comment #4 from Vladimir Makarov <vmakarov at redhat dot com> 2013-02-07
19:24:58 UTC ---
(In reply to comment #3)
> I'd say the bug is in get_reload_reg.
> Changing pseudo 118 in operand 0 of insn 90 on equiv 0
> Changing address in insn 90 r59:DI -- no change
> Changing pseudo 59 in address of insn 90 on equiv 0
> Creating newreg=137, assigning class GENERAL_REGS to address r137
> Choosing alt 1 in insn 90: (0) r (1) rm
> Reuse r137 for reload 0, change to class INDEX_REGS for r137
> 90: flags:CCGC=cmp(r137:DI,[r137:DI])
> Inserting insn reload before:
> 256: r137:DI=0
>
>
> 3065 if (get_reload_reg (type, mode, old, goal_alt[i], "", &new_reg)
> 3066 && type != OP_OUT)
>
> calls it with
> type=OP_IN, mode=SImode, original=const0_rtx, rclass=GENERAL_REGS
> but returns new_reg = (reg:DI 137).
> That is because:
> if (rtx_equal_p (curr_insn_input_reloads[i].input, original)
> && in_class_p (curr_insn_input_reloads[i].reg, rclass, &new_class))
> doesn't check any mode if original (and curr_insn_input_reloads[i].input) are
> VOIDmode as in this case. So, either this can be fixed by doing:
> if (rtx_equal_p (curr_insn_input_reloads[i].input, original)
> - && in_class_p (curr_insn_input_reloads[i].reg, rclass, &new_class))
> + && in_class_p (curr_insn_input_reloads[i].reg, rclass, &new_class)
> + && GET_MODE (curr_insn_input_reloads[i].reg) == mode)
> , or we could try better, if the GET_MODE (curr_insn_input_reloads[i].reg)
> is wider than mode, see if we can create a lowpart subreg thereof and return
> that, and only give up (i.e. continue looping) if creation of the lowpart
> subreg for some reason failed.
>
> Vlad, what do you think?
I think, the second solution with lowpart is better.
Would you like to make a patch or may be you prefer that I work on it?
