[Bug rtl-optimization/83459] [8 Regression] ICE: qsort checking failed: qsort comparator non-negative on sorted output: 1 with --param=sched-pressure-algorithm=2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83459 Wilco changed: What|Removed |Added Status|NEW |RESOLVED CC||wilco at gcc dot gnu.org Resolution|--- |FIXED --- Comment #4 from Wilco --- Fixed in r257481.
[Bug rtl-optimization/83459] [8 Regression] ICE: qsort checking failed: qsort comparator non-negative on sorted output: 1 with --param=sched-pressure-algorithm=2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83459 --- Comment #3 from Wilco --- Author: wilco Date: Thu Feb 8 12:29:28 2018 New Revision: 257481 URL: https://gcc.gnu.org/viewcvs?rev=257481=gcc=rev Log: PR84068, PR83459: Fix sort order of SCHED_PRESSURE_MODEL The comparison function for SCHED_PRESSURE_MODEL is incorrect. If either instruction is not in target_bb, the ordering is not well defined. Since all instructions outside the target_bb get the highest model_index, all we need to do is sort on model_index. If the model_index is the same we defer to RFS_DEP_COUNT and/or RFS_TIE. gcc/ PR rtl-optimization/84068 PR rtl-optimization/83459 * haifa-sched.c (rank_for_schedule): Fix SCHED_PRESSURE_MODEL sorting. gcc/testsuite PR rtl-optimization/84068 PR rtl-optimization/83459 * gcc.dg/pr84068.c: New test. Added: trunk/gcc/testsuite/gcc.dg/pr84068.c Modified: trunk/gcc/ChangeLog trunk/gcc/haifa-sched.c trunk/gcc/testsuite/ChangeLog
[Bug rtl-optimization/83459] [8 Regression] ICE: qsort checking failed: qsort comparator non-negative on sorted output: 1 with --param=sched-pressure-algorithm=2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83459 Martin Liška changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2017-12-20 CC||marxin at gcc dot gnu.org Ever confirmed|0 |1
[Bug rtl-optimization/83459] [8 Regression] ICE: qsort checking failed: qsort comparator non-negative on sorted output: 1 with --param=sched-pressure-algorithm=2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83459
Alexander Monakov changed:
What|Removed |Added
Blocks||82407
--- Comment #2 from Alexander Monakov ---
I agree with the analysis. Insns where INSN_BB (i) != target_bb correspond to
(likely speculative) insns outside of current basic block, so for
SCHED_PRESSURE_MODEL we definitely want to sort them _after_ insns from
target_bb. When both insns are outside of current bb we can defer to next
tiebreakers.
The following (completely untested) patch implements this change. I can run it
through a bootstrap/regtest cycle if it looks reasonable:
diff --git a/gcc/haifa-sched.c b/gcc/haifa-sched.c
index 549e8961411..f169d57a634 100644
--- a/gcc/haifa-sched.c
+++ b/gcc/haifa-sched.c
@@ -2783,12 +2783,20 @@ rank_for_schedule (const void *x, const void *y)
}
/* Prefer instructions that occur earlier in the model schedule. */
- if (sched_pressure == SCHED_PRESSURE_MODEL
- && INSN_BB (tmp) == target_bb && INSN_BB (tmp2) == target_bb)
+ if (sched_pressure == SCHED_PRESSURE_MODEL)
{
- diff = model_index (tmp) - model_index (tmp2);
- gcc_assert (diff != 0);
- return rfs_result (RFS_PRESSURE_INDEX, diff, tmp, tmp2);
+ if (INSN_BB (tmp) == target_bb)
+ {
+ if (INSN_BB (tmp2) == target_bb)
+ {
+ diff = model_index (tmp) - model_index (tmp2);
+ gcc_assert (diff != 0);
+ return rfs_result (RFS_PRESSURE_INDEX, diff, tmp, tmp2);
+ }
+ return rfs_result (RFS_PRESSURE_INDEX, -1, tmp, tmp2);
+ }
+ if (INSN_BB (tmp2) == target_bb)
+ return rfs_result (RFS_PRESSURE_INDEX, 1, tmp, tmp2);
}
/* Prefer the insn which has more later insns that depend on it.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82407
[Bug 82407] [meta-bug] qsort_chk fallout tracking
[Bug rtl-optimization/83459] [8 Regression] ICE: qsort checking failed: qsort comparator non-negative on sorted output: 1 with --param=sched-pressure-algorithm=2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83459
Jakub Jelinek changed:
What|Removed |Added
CC||amonakov at gcc dot gnu.org,
||jakub at gcc dot gnu.org,
||vmakarov at gcc dot gnu.org
--- Comment #1 from Jakub Jelinek ---
So, in this case we have:
(gdb) p debug_rtx (first[0])
(insn 4 2 3 2 (set (reg/v:SI 95 [ e ])
(reg:SI 4 si [ e ])) "pr83459.c":6 86 {*movsi_internal}
(expr_list:REG_DEAD (reg:SI 4 si [ e ])
(nil)))
$21 = void
(gdb) p debug_rtx (first[1])
(insn 15 14 16 4 (set (reg:SI 98 [ b ])
(sign_extend:SI (mem/c:HI (symbol_ref:DI ("b") [flags 0x2] ) [1 b+0 S2 A16]))) "pr83459.c":8 153 {extendhisi2}
(nil))
$22 = void
(gdb) p debug_rtx (first[2])
(insn 9 3 10 2 (set (reg:SI 96 [ a ])
(sign_extend:SI (mem/c:HI (symbol_ref:DI ("a") [flags 0x2] ) [1 a+0 S2 A16]))) "pr83459.c":7 153 {extendhisi2}
(nil))
and
p rank_for_schedule ([0], [1])
$24 = -1
determined by
val = (dep_list_size (tmp2, SD_LIST_FORW)
- dep_list_size (tmp, SD_LIST_FORW));
if (flag_sched_dep_count_heuristic && val != 0)
return rfs_result (RFS_DEP_COUNT, val, tmp, tmp2);
where val is -1, then
p rank_for_schedule ([1], [2])
$25 = -4
determined by:
/* If insns are equally good, sort by INSN_LUID (original insn order),
so that we make the sort stable. This minimizes instruction movement,
thus minimizing sched's effect on debugging and cross-jumping. */
return rfs_result (RFS_TIE, INSN_LUID (tmp) - INSN_LUID (tmp2), tmp, tmp2);
and finally:
p rank_for_schedule ([0], [2])
$26 = 1
determined by:
/* Prefer instructions that occur earlier in the model schedule. */
if (sched_pressure == SCHED_PRESSURE_MODEL
&& INSN_BB (tmp) == target_bb && INSN_BB (tmp2) == target_bb)
{
diff = model_index (tmp) - model_index (tmp2);
gcc_assert (diff != 0);
return rfs_result (RFS_PRESSURE_INDEX, diff, tmp, tmp2);
}
which is checked earliest. If we want a stable sort, I'm afraid for
SCHED_PRESSURE_MODEL we need to sort insns where INSN_BB (tmp) == target_bb and
INSN_BB (tmp2) != target_bb or INSN_BB (tmp2) == target_bb and INSN_BB (tmp) !=
target_bb regardless of dep_list_size.
Thoughts on this?
[Bug rtl-optimization/83459] [8 Regression] ICE: qsort checking failed: qsort comparator non-negative on sorted output: 1 with --param=sched-pressure-algorithm=2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83459 Richard Biener changed: What|Removed |Added Keywords||ice-checking Target Milestone|--- |8.0
