[Bug tree-optimization/97545] New: ICE since commit 90e88fd376b and using selective-scheduling2

[Bug tree-optimization/97545] New: ICE since commit 90e88fd376b and using selective-scheduling2

[stefansf at linux dot ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97545

            Bug ID: 97545
           Summary: ICE since commit 90e88fd376b and using
                    selective-scheduling2
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: stefansf at linux dot ibm.com
  Target Milestone: ---

Created attachment 49433
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49433&action=edit
reduced failing example

Since commit 90e88fd376b compiling the attached program on S/390 results in:

$ gcc -O3 -fselective-scheduling2 t.i
during RTL pass: sched2
: In function 'main':
:67:1: internal compiler error: Segmentation fault
0x21e3323 crash_signal
        /home/stefansf/devel/gcc-2/src/gcc/toplev.c:330
0x171da48 NEXT_INSN(rtx_insn const*)
        /home/stefansf/devel/gcc-2/src/gcc/rtl.h:1469
0x28be551 s390_sched_init
        /home/stefansf/devel/gcc-2/src/gcc/config/s390/s390.c:15129
0x213c1f7 sel_region_init
        /home/stefansf/devel/gcc-2/src/gcc/sel-sched.c:6929
0x213e5d7 sel_sched_region(int)
        /home/stefansf/devel/gcc-2/src/gcc/sel-sched.c:7624
0x213e853 run_selective_scheduling()
        /home/stefansf/devel/gcc-2/src/gcc/sel-sched.c:7720
0x2104d47 rest_of_handle_sched2
        /home/stefansf/devel/gcc-2/src/gcc/sched-rgn.c:3738
0x21050b1 execute
        /home/stefansf/devel/gcc-2/src/gcc/sched-rgn.c:3882
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.

whereas gcc -O3 -fselective-scheduling2 t.i -fevrp-mode=legacy works fine.

It looks like as if current_sched_info->prev_head gets corrupted at some point.
 Adding a breakpoint prior the ICE and then trying to debug print results in:

(gdb) call debug (current_sched_info->prev_head)
(??? bad code 42405
)

[Bug rtl-optimization/97545] ICE since commit r11-3684 and using selective-scheduling2

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97545

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
r11-3684 would have changed IR before selective-scheduling2.