https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80125
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
We trigger:
/* If I2 is a PARALLEL of two SETs of REGs (and perhaps some CLOBBERs),
make those two SETs separate I1 and I2 insns, and make an I0 that is
the original I1. */
if (!HAVE_cc0 && i0 == 0
&& is_parallel_of_n_reg_sets (PATTERN (i2), 2)
&& can_split_parallel_of_n_reg_sets (i2, 2)
&& !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2), 0, 0)), i2, i3)
&& !reg_used_between_p (SET_DEST (XVECEXP (PATTERN (i2), 0, 1)), i2, i3))
{
/* If there is no I1, there is no I0 either. */
i0 = i1;
/* We make I1 with the same INSN_UID as I2. This gives it
the same DF_INSN_LUID for value tracking. Our fake I1 will
never appear in the insn stream so giving it the same INSN_UID
as I2 will not cause a problem. */
i1 = gen_rtx_INSN (VOIDmode, NULL, i2, BLOCK_FOR_INSN (i2),
XVECEXP (PATTERN (i2), 0, 0), INSN_LOCATION (i2),
-1, NULL_RTX);
INSN_UID (i1) = INSN_UID (i2);
SUBST (PATTERN (i2), XVECEXP (PATTERN (i2), 0, 1));
}
and thus i1 really isn't in the insn stream, it only has NEXT_INSN set to i2
(so in the only case where this is passed to can_combine_p succ is that i1 and
succ2 is the i2 right after it).
--- combine.c.jj 2017-03-21 07:57:01.000000000 +0100
+++ combine.c 2017-03-21 09:52:50.564214916 +0100
@@ -1955,7 +1955,7 @@ can_combine_p (rtx_insn *insn, rtx_insn
|| (JUMP_P (i3) && find_reg_note (i3, REG_NON_LOCAL_GOTO, NULL_RTX))
/* Make sure that DEST is not used after INSN but before SUCC, or
between SUCC and SUCC2. */
- || (succ && reg_used_between_p (dest, insn, succ))
+ || (succ && PREV_INSN (succ) && reg_used_between_p (dest, insn, succ))
|| (succ2 && reg_used_between_p (dest, succ, succ2))
/* Make sure that DEST is not used after SUCC but before I3. */
|| (!all_adjacent
fixes the ICE but isn't the right thing.
