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Re: [PATCH] Punt on hard reg setters in modulo sched (PR target/83507)
- From: Richard Biener <rguenther at suse dot de>
- To: Jakub Jelinek <jakub at redhat dot com>,Jeff Law <law at redhat dot com>,Vladimir Makarov <vmakarov at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Tue, 09 Jan 2018 07:56:28 +0100
- Subject: Re: [PATCH] Punt on hard reg setters in modulo sched (PR target/83507)
- Authentication-results: sourceware.org; auth=none
- References: <20180108235904.GY1833@tucnak>
On January 9, 2018 12:59:04 AM GMT+01:00, Jakub Jelinek <jakub@redhat.com> wrote:
>Hi!
>
>SMS is done before reload and assumes it can extend the lifetime by
>making
>copies of the destination registers without trying to re-recognize the
>instructions etc. That can work only with pseudos, for some hard
>registers
>there isn't even a valid move instruction to pseudo (e.g. the powerpc
>CA
>register), for others it can be very much undesirable.
>
>Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
Richard.
>2018-01-09 Jakub Jelinek <jakub@redhat.com>
>
> PR target/83507
> * modulo-sched.c (schedule_reg_moves): Punt if we'd need to move
> hard registers. Formatting fixes.
>
> * gcc.dg/sms-13.c: New test.
>
>--- gcc/modulo-sched.c.jj 2018-01-03 10:19:55.710534046 +0100
>+++ gcc/modulo-sched.c 2018-01-08 16:53:01.232465389 +0100
>@@ -687,9 +687,9 @@ schedule_reg_moves (partial_schedule_ptr
> rtx set = single_set (u->insn);
>
> /* Skip instructions that do not set a register. */
>- if ((set && !REG_P (SET_DEST (set))))
>+ if (set && !REG_P (SET_DEST (set)))
> continue;
>-
>+
> /* Compute the number of reg_moves needed for u, by looking at life
> ranges started at u (excluding self-loops). */
> distances[0] = distances[1] = false;
>@@ -743,7 +743,10 @@ schedule_reg_moves (partial_schedule_ptr
> first_move += ps->g->num_nodes;
>
> /* Generate each move. */
>- old_reg = prev_reg = SET_DEST (single_set (u->insn));
>+ old_reg = prev_reg = SET_DEST (set);
>+ if (HARD_REGISTER_P (old_reg))
>+ return false;
>+
> for (i_reg_move = 0; i_reg_move < nreg_moves; i_reg_move++)
> {
> ps_reg_move_info *move = ps_reg_move (ps, first_move + i_reg_move);
>--- gcc/testsuite/gcc.dg/sms-13.c.jj 2018-01-08 17:00:16.427534076
>+0100
>+++ gcc/testsuite/gcc.dg/sms-13.c 2018-01-08 16:56:15.704496101 +0100
>@@ -0,0 +1,32 @@
>+/* PR target/83507 */
>+/* { dg-do compile } */
>+/* { dg-options "-O2 -fmodulo-sched -fno-tree-ter
>-fno-tree-coalesce-vars" } */
>+
>+void
>+foo (unsigned short int x, unsigned char y)
>+{
>+ unsigned char *a = &y;
>+ unsigned short int b;
>+ int c;
>+
>+ while (y < 3)
>+ {
>+ if (x != 0)
>+ ++y;
>+ ++y;
>+ }
>+
>+ for (c = 0; c < 5; ++c)
>+ {
>+ int d = 1;
>+ d += b > x;
>+ y &= d;
>+ }
>+
>+ do
>+ {
>+ c += y;
>+ x = c;
>+ }
>+ while (x != 0);
>+}
>
> Jakub