[Bug tree-optimization/111878] New: [14 Regression] ICE: in get_loop_exit_edges, at cfgloop.cc:1204 with -O3 -fgraphite-identity -fsave-optimization-record

[Bug tree-optimization/111878] New: [14 Regression] ICE: in get_loop_exit_edges, at cfgloop.cc:1204 with -O3 -fgraphite-identity -fsave-optimization-record

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111878

            Bug ID: 111878
           Summary: [14 Regression] ICE: in get_loop_exit_edges, at
                    cfgloop.cc:1204 with -O3 -fgraphite-identity
                    -fsave-optimization-record
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code
          Severity: normal
          Priority: P3
         Component: tree-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 56151
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56151&action=edit
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-gcc -O3 -fgraphite-identity -fsave-optimization-record
testcase.c
during GIMPLE pass: graphite
testcase.c: In function 'long_c2i':
testcase.c:5:1: internal compiler error: in get_loop_exit_edges, at
cfgloop.cc:1204
    5 | long_c2i (long utmp, int i)
      | ^~~~~~~~
0x71d5c7 get_loop_exit_edges(loop const*, basic_block_def**)
        /repo/gcc-trunk/gcc/cfgloop.cc:1204
0x177ed5e find_loop_location(loop*)
        /repo/gcc-trunk/gcc/tree-vect-loop-manip.cc:1844
0x25dd9db graphite_transform_loops()
        /repo/gcc-trunk/gcc/graphite.cc:478
0x25ddb70 graphite_transforms
        /repo/gcc-trunk/gcc/graphite.cc:541
0x25ddb70 execute
        /repo/gcc-trunk/gcc/graphite.cc:620
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
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-13-branch/binary-latest-amd64/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-13-branch/binary-13-branch-20231014001921-ga9f39860efa-checking-yes-rtl-df-extra-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/13.2.1/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-13-branch//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--with-cloog --with-ppl --with-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-13-branch//binary-13-branch-20231014001921-ga9f39860efa-checking-yes-rtl-df-extra-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 13.2.1 20231014 (GCC)

[Bug tree-optimization/111878] [14 Regression] ICE: in get_loop_exit_edges, at cfgloop.cc:1204 with -O3 -fgraphite-identity -fsave-optimization-record

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111878

--- Comment #1 from Zdenek Sojka <zsojka at seznam dot cz> ---
The correct version output for gcc-14 is:
$ 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-r14-4743-20231019111223-g947fb34a165-checking-yes-rtl-df-extra-nobootstrap-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/14.0.0/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 --with-cloog --with-ppl --with-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-r14-4743-20231019111223-g947fb34a165-checking-yes-rtl-df-extra-nobootstrap-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 14.0.0 20231019 (experimental) (GCC)

[Bug tree-optimization/111878] [14 Regression] ICE: in get_loop_exit_edges, at cfgloop.cc:1204 with -O3 -fgraphite-identity -fsave-optimization-record

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111878

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0

[Bug tree-optimization/111878] [14 Regression] ICE: in get_loop_exit_edges, at cfgloop.cc:1204 with -O3 -fgraphite-identity -fsave-optimization-record

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111878

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-10-19
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
`-O3 -fgraphite-identity -fdump-tree-graphite` will also cause the ICE.

The code in graphite is:
            dump_user_location_t loc = find_loop_location
              (scops[i]->scop_info->region.entry->dest->loop_father);
            dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, loc,
                             "loop nest optimized\n");

[Bug tree-optimization/111878] [14 Regression] ICE: in get_loop_exit_edges, at cfgloop.cc:1204 with -O3 -fgraphite-identity -fsave-optimization-record/-fdump-tree-graphite

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111878

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[14 Regression] ICE: in     |[14 Regression] ICE: in
                   |get_loop_exit_edges, at     |get_loop_exit_edges, at
                   |cfgloop.cc:1204 with -O3    |cfgloop.cc:1204 with -O3
                   |-fgraphite-identity         |-fgraphite-identity
                   |-fsave-optimization-record  |-fsave-optimization-record/
                   |                            |-fdump-tree-graphite

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
If we wrap the whole function inside a loop, there is no crash.
That is:
```
int long_c2i_ltmp;
int *long_c2i_cont;

void
long_c2i (long utmp, int i)
{
  for(int j = 0; j < 100; j++)
         {
  int neg = 1;
  switch (long_c2i_cont[0])
    case 0:
    neg = 0;

  for (; i; i++)
    if (neg)
      utmp |= long_c2i_cont[i] ^ 5;
    else
      utmp |= long_c2i_cont[i];
  long_c2i_ltmp = utmp;
         }
}
```

That is because the loop that is being chosen here for the `->loop_father` is
the outer most loop (that was just added).

[Bug tree-optimization/111878] [14 Regression] ICE: in get_loop_exit_edges, at cfgloop.cc:1204 with -O3 -fgraphite-identity -fsave-optimization-record/-fdump-tree-graphite/-fopt-info

[jamborm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111878

--- Comment #4 from Martin Jambor <jamborm at gcc dot gnu.org> ---
I am not 100% certain if it is the same bug (I am happy to open a separate bug
report if not), but I'm getting an ICE on the same spot, also with graphite,
when running

gfortran ~/gcc/trunk/src/libgomp/testsuite/libgomp.fortran/simd7.f90
-floop-nest-optimize -O1

with master revision 89e97f655d6 gfortran (and the above libgomp test).

[Bug tree-optimization/111878] [14 Regression] ICE: in get_loop_exit_edges, at cfgloop.cc:1204 with -O3 -fgraphite-identity -fsave-optimization-record/-fdump-tree-graphite/-fopt-info

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111878

--- Comment #5 from Sam James <sjames at gcc dot gnu.org> ---
Again suppressed by -fharden-control-flow-redundancy.

Anyway, will bisect.

[Bug tree-optimization/111878] [14 Regression] ICE: in get_loop_exit_edges, at cfgloop.cc:1204 with -O3 -fgraphite-identity -fsave-optimization-record/-fdump-tree-graphite/-fopt-info since r14-4708-gd65e38e616e7ac

[sjames at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111878

Sam James <sjames at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tnfchris at gcc dot gnu.org
            Summary|[14 Regression] ICE: in     |[14 Regression] ICE: in
                   |get_loop_exit_edges, at     |get_loop_exit_edges, at
                   |cfgloop.cc:1204 with -O3    |cfgloop.cc:1204 with -O3
                   |-fgraphite-identity         |-fgraphite-identity
                   |-fsave-optimization-record/ |-fsave-optimization-record/
                   |-fdump-tree-graphite/-fopt- |-fdump-tree-graphite/-fopt-
                   |info                        |info since
                   |                            |r14-4708-gd65e38e616e7ac

--- Comment #6 from Sam James <sjames at gcc dot gnu.org> ---
d65e38e616e7ac8157ef04b55beb6670f2c0f142 is the first bad commit
commit d65e38e616e7ac8157ef04b55beb6670f2c0f142
Author: Tamar Christina <tamar.christina@arm.com>
Date:   Wed Oct 18 09:02:12 2023 +0100

    middle-end: Refactor vectorizer loop conditionals and separate out IV to
new variables

i.e. r14-4708-gd65e38e616e7ac

[Bug tree-optimization/111878] [14 Regression] ICE: in get_loop_exit_edges, at cfgloop.cc:1204 with -O3 -fgraphite-identity -fsave-optimization-record/-fdump-tree-graphite/-fopt-info since r14-4708-gd65e38e616e7ac

[tnfchris at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111878

Tamar Christina <tnfchris at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |tnfchris at gcc dot gnu.org

--- Comment #7 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
Thanks for the report.

Graphite is feeding it a junk loop.  The loop's latch block is invalid. In fact
the block isn't even part of the loop.

Since the loop structure Graphite passes it is broken, get_loop_exit_edges (..)
asserts.

Previously for this situation the call would silently return NULL for such
loops.
I'd argue this is a bug in Graphite, but will restore the return NULL for
broken loops.

[Bug tree-optimization/111878] [14 Regression] ICE: in get_loop_exit_edges, at cfgloop.cc:1204 with -O3 -fgraphite-identity -fsave-optimization-record/-fdump-tree-graphite/-fopt-info since r14-4708-gd65e38e616e7ac

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111878

--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tamar Christina <tnfchris@gcc.gnu.org>:

https://gcc.gnu.org/g:7a496b7ce105185be12e023e749c90d5f7561879

commit r14-5529-g7a496b7ce105185be12e023e749c90d5f7561879
Author: Tamar Christina <tamar.christina@arm.com>
Date:   Thu Nov 16 12:11:22 2023 +0000

    middle-end: skip checking loop exits if loop malformed [PR111878]

    Before my refactoring if the loop->latch was incorrect then
find_loop_location
    skipped checking the edges and would eventually return a dummy location.

    It turns out that a loop can have
    loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS) but also not have a
latch
    in which case get_loop_exit_edges traps.

    This restores the old behavior.

    gcc/ChangeLog:

            PR tree-optimization/111878
            * tree-vect-loop-manip.cc (find_loop_location): Skip edges check if
            latch incorrect.

    gcc/testsuite/ChangeLog:

            PR tree-optimization/111878
            * gcc.dg/graphite/pr111878.c: New test.

[Bug tree-optimization/111878] [14 Regression] ICE: in get_loop_exit_edges, at cfgloop.cc:1204 with -O3 -fgraphite-identity -fsave-optimization-record/-fdump-tree-graphite/-fopt-info since r14-4708-gd65e38e616e7ac

[tnfchris at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111878

Tamar Christina <tnfchris at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #9 from Tamar Christina <tnfchris at gcc dot gnu.org> ---
Fixed, thanks for the report.