[Bug rtl-optimization/100239] New: [10/11/12 Regression] ICE: in expand_expr_real_2, at expr.c:9865 with __builtin_shuffle()

[Bug rtl-optimization/100239] New: [10/11/12 Regression] ICE: in expand_expr_real_2, at expr.c:9865 with __builtin_shuffle()

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100239

            Bug ID: 100239
           Summary: [10/11/12 Regression] ICE: in expand_expr_real_2, at
                    expr.c:9865 with __builtin_shuffle()
           Product: gcc
           Version: 12.0
            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

Created attachment 50663
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50663&action=edit
reduced testcase

Compiler output:
$ x86_64-pc-linux-gnu-gcc testcase.c
during RTL pass: expand
testcase.c: In function 'foo':
testcase.c:9:7: internal compiler error: in expand_expr_real_2, at expr.c:9865
    9 |   c & __builtin_shuffle (v != v, 0 < (V){}, (V){719} >>5);
      |       ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
0x671830 expand_expr_real_2(separate_ops*, rtx_def*, machine_mode,
expand_modifier)
        /repo/gcc-trunk/gcc/expr.c:9865
0xb94d3f expand_gimple_stmt_1
        /repo/gcc-trunk/gcc/cfgexpand.c:3947
0xb94d3f expand_gimple_stmt
        /repo/gcc-trunk/gcc/cfgexpand.c:4008
0xb9a5d1 expand_gimple_basic_block
        /repo/gcc-trunk/gcc/cfgexpand.c:6045
0xb9c246 execute
        /repo/gcc-trunk/gcc/cfgexpand.c:6729
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-r12-96-20210423095621-g886b6c1e8af-checking-yes-rtl-df-extra-nobootstrap-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/12.0.0/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-r12-96-20210423095621-g886b6c1e8af-checking-yes-rtl-df-extra-nobootstrap-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.0.0 20210423 (experimental) (GCC)

[Bug rtl-optimization/100239] [10/11/12 Regression] ICE: in expand_expr_real_2, at expr.c:9865 with __builtin_shuffle()

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100239

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org
   Last reconfirmed|                            |2021-04-23
                 CC|                            |jakub at gcc dot gnu.org
           Priority|P3                          |P2
   Target Milestone|---                         |10.4
             Status|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with my r10-1201-g2e83f583c27ef7a9d3b0fb0b5ed372439d6222a8
I'll have a look.

[Bug tree-optimization/100239] [10/11/12 Regression] ICE: in expand_expr_real_2, at expr.c:9865 with __builtin_shuffle()

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100239

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 50678
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=50678&action=edit
gcc11-pr100239.patch

Untested fix.

[Bug tree-optimization/100239] [10/11/12 Regression] ICE: in expand_expr_real_2, at expr.c:9865 with __builtin_shuffle()

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100239

--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:83d26d0e1b3625ab6c2d83610a13976b52f63e0a

commit r12-159-g83d26d0e1b3625ab6c2d83610a13976b52f63e0a
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Apr 27 15:42:47 2021 +0200

    veclower: Fix up vec_shl matching of VEC_PERM_EXPR [PR100239]

    The following testcase ICEs at -O0, because lower_vec_perm sees the
      _1 = { 0, 0, 0, 0, 0, 0, 0, 0 };
      _2 = VEC_COND_EXPR <_1, { -1, -1, -1, -1, -1, -1, -1, -1 }, { 0, 0, 0, 0,
0, 0, 0, 0 }>;
      _3 = { 6, 0, 0, 0, 0, 0, 0, 0 };
      _4 = VEC_PERM_EXPR <{ 0, 0, 0, 0, 0, 0, 0, 0 }, _2, _3>;
    and as the ISA is SSE2, there is no support for the particular permutation
    nor for variable mask permutation.  But, the code to match vec_shl matches
    it, because the permutation has the first operand a zero vector and the
    mask picks all elements randomly from that vector.
    So, in the end that isn't a vec_shl, but the permutation could be in theory
    optimized into the first argument.  As we keep it as is, it will fail
    during expansion though, because that for vec_shl correctly requires that
    it actually is a shift:
          unsigned firstidx = 0;
          for (unsigned int i = 0; i < nelt; i++)
            {
              if (known_eq (sel[i], nelt))
                {
                  if (i == 0 || firstidx)
                    return NULL_RTX;
                  firstidx = i;
                }
              else if (firstidx
                       ? maybe_ne (sel[i], nelt + i - firstidx)
                       : maybe_ge (sel[i], nelt))
                return NULL_RTX;
            }

          if (firstidx == 0)
            return NULL_RTX;
          first = firstidx;
    The if (firstidx == 0) return NULL; is what is missing a counterpart
    on the lower_vec_perm side.
    As with optimize != 0 we fold it in other spots, I think it is not needed
    to optimize this cornercase in lower_vec_perm (which would mean we'd need
    to recurse on the newly created _4 = { 0, 0, 0, 0, 0, 0, 0, 0 };
    whether it is supported or not).

    2021-04-27  Jakub Jelinek  <jakub@redhat.com>

            PR tree-optimization/100239
            * tree-vect-generic.c (lower_vec_perm): Don't accept constant
            permutations with all indices from the first zero element as
vec_shl.

            * gcc.dg/pr100239.c: New test.

[Bug tree-optimization/100239] [10/11/12 Regression] ICE: in expand_expr_real_2, at expr.c:9865 with __builtin_shuffle()

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100239

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Jakub Jelinek
<jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:80dc24f813a9d8951d75eea7324f6d713b872bca

commit r11-8300-g80dc24f813a9d8951d75eea7324f6d713b872bca
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Tue Apr 27 15:42:47 2021 +0200

    veclower: Fix up vec_shl matching of VEC_PERM_EXPR [PR100239]

    The following testcase ICEs at -O0, because lower_vec_perm sees the
      _1 = { 0, 0, 0, 0, 0, 0, 0, 0 };
      _2 = VEC_COND_EXPR <_1, { -1, -1, -1, -1, -1, -1, -1, -1 }, { 0, 0, 0, 0,
0, 0, 0, 0 }>;
      _3 = { 6, 0, 0, 0, 0, 0, 0, 0 };
      _4 = VEC_PERM_EXPR <{ 0, 0, 0, 0, 0, 0, 0, 0 }, _2, _3>;
    and as the ISA is SSE2, there is no support for the particular permutation
    nor for variable mask permutation.  But, the code to match vec_shl matches
    it, because the permutation has the first operand a zero vector and the
    mask picks all elements randomly from that vector.
    So, in the end that isn't a vec_shl, but the permutation could be in theory
    optimized into the first argument.  As we keep it as is, it will fail
    during expansion though, because that for vec_shl correctly requires that
    it actually is a shift:
          unsigned firstidx = 0;
          for (unsigned int i = 0; i < nelt; i++)
            {
              if (known_eq (sel[i], nelt))
                {
                  if (i == 0 || firstidx)
                    return NULL_RTX;
                  firstidx = i;
                }
              else if (firstidx
                       ? maybe_ne (sel[i], nelt + i - firstidx)
                       : maybe_ge (sel[i], nelt))
                return NULL_RTX;
            }

          if (firstidx == 0)
            return NULL_RTX;
          first = firstidx;
    The if (firstidx == 0) return NULL; is what is missing a counterpart
    on the lower_vec_perm side.
    As with optimize != 0 we fold it in other spots, I think it is not needed
    to optimize this cornercase in lower_vec_perm (which would mean we'd need
    to recurse on the newly created _4 = { 0, 0, 0, 0, 0, 0, 0, 0 };
    whether it is supported or not).

    2021-04-27  Jakub Jelinek  <jakub@redhat.com>

            PR tree-optimization/100239
            * tree-vect-generic.c (lower_vec_perm): Don't accept constant
            permutations with all indices from the first zero element as
vec_shl.

            * gcc.dg/pr100239.c: New test.

    (cherry picked from commit 83d26d0e1b3625ab6c2d83610a13976b52f63e0a)

[Bug tree-optimization/100239] [10 Regression] ICE: in expand_expr_real_2, at expr.c:9865 with __builtin_shuffle()

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100239

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[10/11/12 Regression] ICE:  |[10 Regression] ICE: in
                   |in expand_expr_real_2, at   |expand_expr_real_2, at
                   |expr.c:9865 with            |expr.c:9865 with
                   |__builtin_shuffle()         |__builtin_shuffle()

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Fixed on the trunk and for 11.2 so far.

[Bug tree-optimization/100239] [10 Regression] ICE: in expand_expr_real_2, at expr.c:9865 with __builtin_shuffle()

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100239

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|10.4                        |10.5

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 10.4 is being released, retargeting bugs to GCC 10.5.

[Bug tree-optimization/100239] [10 Regression] ICE: in expand_expr_real_2, at expr.c:9865 with __builtin_shuffle()

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100239

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |11.2.0
      Known to fail|                            |10.5.0
             Status|ASSIGNED                    |RESOLVED
   Target Milestone|10.5                        |11.2
         Resolution|---                         |FIXED

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed in GCC 11.2.