[Bug rtl-optimization/83459] New: [8 Regression] ICE: qsort checking failed: qsort comparator non-negative on sorted output: 1 with --param=sched-pressure-algorithm=2

["zsojka at seznam dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83459

            Bug ID: 83459
           Summary: [8 Regression] ICE: qsort checking failed: qsort
                    comparator non-negative on sorted output: 1 with
                    --param=sched-pressure-algorithm=2
           Product: gcc
           Version: 8.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu

Created attachment 42899
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42899&action=edit
reduced testcase

This ICE has been reproducing with various testcases, but the used command line
switches were needed for all of them (only opt. level and
max-sched-extend-regions-iters=n value varies).

Compiler output:
$ x86_64-pc-linux-gnu-gcc -Og -fschedule-insns -fsched-pressure
-fno-sched-critical-path-heuristic -fno-sched-rank-heuristic
--param=max-sched-extend-regions-iters=2 --param=sched-pressure-algorithm=2
testcase.c
testcase.c: In function 'c':
testcase.c:9:1: error: qsort comparator non-negative on sorted output: 1
 }
 ^
during RTL pass: sched1
testcase.c:9:1: internal compiler error: qsort checking failed
0x6be441 qsort_chk_error
        /repo/gcc-trunk/gcc/vec.c:222
0x1779f5a qsort_chk(void*, unsigned long, unsigned long, int (*)(void const*,
void const*))
        /repo/gcc-trunk/gcc/vec.c:274
0x1683338 ready_sort_real
        /repo/gcc-trunk/gcc/haifa-sched.c:3087
0x168c6d2 schedule_block(basic_block_def**, void*)
        /repo/gcc-trunk/gcc/haifa-sched.c:6675
0xcd688a schedule_region
        /repo/gcc-trunk/gcc/sched-rgn.c:3174
0xcd688a schedule_insns()
        /repo/gcc-trunk/gcc/sched-rgn.c:3513
0xcd6cb3 schedule_insns()
        /repo/gcc-trunk/gcc/sched-rgn.c:3498
0xcd6cb3 rest_of_handle_sched
        /repo/gcc-trunk/gcc/sched-rgn.c:3717
0xcd6cb3 execute
        /repo/gcc-trunk/gcc/sched-rgn.c:3825
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.


$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-amd64/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-255776-checking-yes-rtl-df-extra-nobootstrap-nographite-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/8.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--disable-bootstrap --without-cloog --without-ppl --without-isl
--build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu
--target=x86_64-pc-linux-gnu --with-ld=/usr/bin/x86_64-pc-linux-gnu-ld
--with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-255776-checking-yes-rtl-df-extra-nobootstrap-nographite-amd64
Thread model: posix
gcc version 8.0.0 20171218 (experimental) (GCC) 

Tested revisions:
r255776 - ICE
r255386 - ICE
7-branch r255536 - OK