On Sun, Jan 06, 2013 at 04:48:03PM +0100, Uros Bizjak wrote:
> --- df-problems.c (revision 194945)
> +++ df-problems.c (working copy)
> @@ -3916,6 +3916,10 @@ can_move_insns_across (rtx from, rtx to, rtx acros
> break;
> if (NONDEBUG_INSN_P (insn))
> {
> + /* Do not move unspec_volatile insns. */
> + if (GET_CODE (PATTERN (insn)) == UNSPEC_VOLATILE)
> + break;
> +
Shouldn't UNSPEC_VOLATILE be handled similarly in the across_from ..
across_to loop? Both UNSPEC_VOLATILE and volatile asm are handled there
just with
trapping_insns_in_across |= may_trap_p (PATTERN (insn));
but your new change doesn't prevent moving just trapping insns across
UNSPEC_VOLATILE, but any insns whatsoever. So supposedly for UNSPEC_VOLATILE
the first loop should just return false; (or fail = 1; ?).
For asm volatile I guess the code is fine as is, it must always describe
what exactly it modifies, so supposedly non-trapping insns can be moved
across asm volatile.
> if (may_trap_or_fault_p (PATTERN (insn))
> && (trapping_insns_in_across || other_branch_live != NULL))
> break;
You could do the check only for may_trap_or_fault_p, all UNSPEC_VOLATILE
may trap.
BTW, can't UNSPEC_VOLATILE be embedded deeply in the pattern?
So volatile_insn_p (insn) && asm_noperands (PATTERN (insn)) == -1?
But perhaps you want to treat that way only UNSPEC_VOLATILE directly in the
pattern and all other UNSPEC_VOLATILE insns must describe in detail what
exactly they are changing? This really needs to be better documented.
Jakub
