[Bug tree-optimization/103800] New: ICE in vectorizable_phi, at tree-vect-loop.c:7861 with -O3 -march=skylake-avx512

[Bug tree-optimization/103800] New: ICE in vectorizable_phi, at tree-vect-loop.c:7861 with -O3 -march=skylake-avx512

[vsevolod.livinskij at frtk dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103800

            Bug ID: 103800
           Summary: ICE in vectorizable_phi, at tree-vect-loop.c:7861 with
                    -O3 -march=skylake-avx512
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vsevolod.livinskij at frtk dot ru
  Target Milestone: ---

Link to the Compiler Explorer: https://godbolt.org/z/bWdof9c8s
Reproducer:
int a;
long b;
extern int c[], d[];
extern bool e[];
void f() {
  if (a)
    ;
  for (;;) {
    for (int g = 2; g; g = a)
      d[g] = 0;
    for (int h = 1; h < 13; h++)
      e[h] = b ? (short)c[4 + h - 1] : c[4 + h - 1];
  }
}


Error:
>$ g++ -O3 -march=skylake-avx512 -c func.cpp
during GIMPLE pass: slp
func.cpp: In function 'void f()':
func.cpp:5:6: internal compiler error: in vectorizable_phi, at
tree-vect-loop.c:7861
    5 | void f() {
      |      ^
0x8bca05 vectorizable_phi(vec_info*, _stmt_vec_info*, gimple**, _slp_tree*,
vec<stmt_info_for_cost, va_heap, vl_ptr>*)
        /testing/gcc/gcc_src_master/gcc/tree-vect-loop.c:7861
0x20abd84 vect_analyze_stmt(vec_info*, _stmt_vec_info*, bool*, _slp_tree*,
_slp_instance*, vec<stmt_info_for_cost, va_heap, vl_ptr>*)
        /testing/gcc/gcc_src_master/gcc/tree-vect-stmts.c:11125
0x14a2186 vect_slp_analyze_node_operations_1
        /testing/gcc/gcc_src_master/gcc/tree-vect-slp.c:4481
0x14a2186 vect_slp_analyze_node_operations
        /testing/gcc/gcc_src_master/gcc/tree-vect-slp.c:4640
0x14a2097 vect_slp_analyze_node_operations
        /testing/gcc/gcc_src_master/gcc/tree-vect-slp.c:4620
0x14a2097 vect_slp_analyze_node_operations
        /testing/gcc/gcc_src_master/gcc/tree-vect-slp.c:4620
0x14a2097 vect_slp_analyze_node_operations
        /testing/gcc/gcc_src_master/gcc/tree-vect-slp.c:4620
0x14a4811 vect_slp_analyze_operations(vec_info*)
        /testing/gcc/gcc_src_master/gcc/tree-vect-slp.c:4879
0x14a9605 vect_slp_analyze_bb_1
        /testing/gcc/gcc_src_master/gcc/tree-vect-slp.c:5817
0x14a9605 vect_slp_region
        /testing/gcc/gcc_src_master/gcc/tree-vect-slp.c:5864
0x14aae33 vect_slp_bbs
        /testing/gcc/gcc_src_master/gcc/tree-vect-slp.c:6056
0x14ab22c vect_slp_function(function*)
        /testing/gcc/gcc_src_master/gcc/tree-vect-slp.c:6144
0x14b1c82 execute
        /testing/gcc/gcc_src_master/gcc/tree-vectorizer.c:1503
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.

GCC version:
gcc version 12.0.0 20211219 (fcbf94a5be9e0c1ecad92da773a6632b86b7f70a) (GCC)

[Bug tree-optimization/103800] [12 Regression] ICE in vectorizable_phi, at tree-vect-loop.c:7861 with -O3

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103800

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-12-22
           Keywords|                            |needs-bisection
   Target Milestone|---                         |12.0
            Summary|[12 Regression] ICE in      |[12 Regression] ICE in
                   |vectorizable_phi, at        |vectorizable_phi, at
                   |tree-vect-loop.c:7861 with  |tree-vect-loop.c:7861 with
                   |-O3 -march=skylake-avx512   |-O3
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
You don't even need to have -march=skylake-avx512.

[Bug tree-optimization/103800] [12 Regression] ICE in vectorizable_phi, at tree-vect-loop.c:7861 with -O3 since r12-5626-g0194d92c35ca8b3a

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103800

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|needs-bisection             |
            Summary|[12 Regression] ICE in      |[12 Regression] ICE in
                   |vectorizable_phi, at        |vectorizable_phi, at
                   |tree-vect-loop.c:7861 with  |tree-vect-loop.c:7861 with
                   |-O3                         |-O3 since
                   |                            |r12-5626-g0194d92c35ca8b3a
                 CC|                            |marxin at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org

--- Comment #2 from Martin Liška <marxin at gcc dot gnu.org> ---
Started with r12-5626-g0194d92c35ca8b3a.

[Bug tree-optimization/103800] [12 Regression] ICE in vectorizable_phi, at tree-vect-loop.c:7861 with -O3 since r12-5626-g0194d92c35ca8b3a

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103800

Martin Liška <marxin at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1

[Bug tree-optimization/103800] [12 Regression] ICE in vectorizable_phi, at tree-vect-loop.c:7861 with -O3 since r12-5626-g0194d92c35ca8b3a

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103800

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Mine.

[Bug tree-optimization/103800] [12 Regression] ICE in vectorizable_phi, at tree-vect-loop.c:7861 with -O3 since r12-5626-g0194d92c35ca8b3a

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103800

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
So in this case we have an SLP tree for a merge PHI with scalar bools where
we do

t.c:10:12: note:   using boolean precision 32 for iftmp.1_168 = pretmp_175 !=
0;
t.c:10:12: note:   using boolean precision 16 for _177 = _176 != 0;
t.c:10:12: note:   using boolean precision 16 for iftmp.1_173 = PHI
<iftmp.1_168(6), _177(7)>

but pattern detection doesn't have any code to insert compensation on PHI
edges.

We now detect the mismatch but I fell foul of thinking it can only happen for
non-bool vs. bool context ...

[Bug tree-optimization/103800] [12 Regression] ICE in vectorizable_phi, at tree-vect-loop.c:7861 with -O3 since r12-5626-g0194d92c35ca8b3a

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103800

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:88e861655b3e59bc982ba22cd6e2e7348efae866

commit r12-6211-g88e861655b3e59bc982ba22cd6e2e7348efae866
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Jan 4 15:49:50 2022 +0100

    tree-optimization/103800 - sanity check more PHI vectorization

    Bool pattern detection doesn't really handle PHIs well so we have
    to be prepared for mismatched vector types in more cases than
    originally thought.

    2022-01-04  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/103800
            * tree-vect-loop.c (vectorizable_phi): Remove assert and
            expand comment.

            * gcc.dg/vect/bb-slp-pr103800.c: New testcase.

[Bug tree-optimization/103800] [12 Regression] ICE in vectorizable_phi, at tree-vect-loop.c:7861 with -O3 since r12-5626-g0194d92c35ca8b3a

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103800

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

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

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.