Ping?
On Wed, 7 Sep 2011, Alexander Monakov wrote:
> Hello,
>
> The patch repairs a problem when we attempt to substitute an insn like
> (... (cmp (mem (reg:DI ax)) (reg:SI ax))) (note different modes) through
> (set (reg:DI ax) (reg:DI dx)), which leaves the (reg:SI ax) part of the
> comparison intact, causing an ICE later on when we notice that the dependency
> on ax is still present. As this is quite rare, we can simply forbid
> substitution in such circumstances, much like substitution of multiple hard
> reg references is forbidden now.
>
> En passant, the patch simplifes the code a little, as we never try to
> substitute anything but registers.
>
> Bootstrapped and regtested on x86_64-linux with sel-sched enabled at -O2, OK?
> (I'll add the testcase from Bugzilla when committing)
>
> 2011-09-07 Alexander Monakov <amona...@ispras.ru>
>
> PR rtl-optimization/50205
> * sel-sched.c (count_occurrences_1): Simplify on the assumption that
> p->x is a register. Forbid substitution when the same register is
> found in a different mode.
> (count_occurrences_equiv): Assert that 'what' is a register.
>
> diff --git a/gcc/sel-sched.c b/gcc/sel-sched.c
> index f11faca..2af01ae 100644
> --- a/gcc/sel-sched.c
> +++ b/gcc/sel-sched.c
> @@ -813,18 +813,12 @@ count_occurrences_1 (rtx *cur_rtx, void *arg)
> {
> rtx_search_arg_p p = (rtx_search_arg_p) arg;
>
> - /* The last param FOR_GCSE is true, because otherwise it performs excessive
> - substitutions like
> - r8 = r33
> - r16 = r33
> - for the last insn it presumes r33 equivalent to r8, so it changes it to
> - r33. Actually, there's no change, but it spoils debugging. */
> - if (exp_equiv_p (*cur_rtx, p->x, 0, true))
> - {
> - /* Bail out if we occupy more than one register. */
> - if (REG_P (*cur_rtx)
> - && HARD_REGISTER_P (*cur_rtx)
> - && hard_regno_nregs[REGNO(*cur_rtx)][GET_MODE (*cur_rtx)] > 1)
> + if (REG_P (*cur_rtx) && REGNO (*cur_rtx) == REGNO (p->x))
> + {
> + /* Bail out if mode is different or more than one register is used. */
> + if (GET_MODE (*cur_rtx) != GET_MODE (p->x)
> + || (HARD_REGISTER_P (*cur_rtx)
> + && hard_regno_nregs[REGNO(*cur_rtx)][GET_MODE (*cur_rtx)] > 1))
> {
> p->n = 0;
> return 1;
> @@ -837,7 +831,6 @@ count_occurrences_1 (rtx *cur_rtx, void *arg)
> }
>
> if (GET_CODE (*cur_rtx) == SUBREG
> - && REG_P (p->x)
> && (!REG_P (SUBREG_REG (*cur_rtx))
> || REGNO (SUBREG_REG (*cur_rtx)) == REGNO (p->x)))
> {
> @@ -859,6 +852,7 @@ count_occurrences_equiv (rtx what, rtx where)
> {
> struct rtx_search_arg arg;
>
> + gcc_assert (REG_P (what));
> arg.x = what;
> arg.n = 0;
>
>
>
