[Bug c/65961] New: ice in vect_is_simple_use_1 with -O3

[Bug c/65961] New: ice in vect_is_simple_use_1 with -O3

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65961

            Bug ID: 65961
           Summary: ice in vect_is_simple_use_1 with -O3
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

Created attachment 35435
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35435&action=edit
C source code

The attached code, when compiled by gcc trunk dated 20150429
and with flag -O3, says this:

qshs.c: In function ‘shs1’:
qshs.c:136:1: internal compiler error: in vect_is_simple_use_1, at
tree-vect-stmts.c:7867
0xdca504 vect_is_simple_use_1(tree_node*, gimple_statement_base*,
_loop_vec_info*, _bb_vec_info*, gimple_statement_base**, tree_node**,
vect_def_type*, tree_node**)
    ../../src/trunk/gcc/tree-vect-stmts.c:7867
0xdd3d5a vectorizable_operation
    ../../src/trunk/gcc/tree-vect-stmts.c:4676
0xddc731 vect_analyze_stmt(gimple_statement_base*, bool*, _slp_tree*)
    ../../src/trunk/gcc/tree-vect-stmts.c:7196
0xdf1319 vect_slp_analyze_node_operations
    ../../src/trunk/gcc/tree-vect-slp.c:2094

tree-vect-stmts.c:7867 is

    gcc_assert (*vectype != NULL_TREE);
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From: "basile at opensource dot dyc.edu" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c/65958] -fstack-check breaks __builtin(alloca)
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ide958

Anthony G. Basile <basile at opensource dot dyc.edu> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |basile at opensource dot dyc.edu

--- Comment #1 from Anthony G. Basile <basile at opensource dot dyc.edu> ---
We should add that we've only seen this on arm arch.

[Bug tree-optimization/65961] [6 Regression] ice in vect_is_simple_use_1 with -O3

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65961

Markus Trippelsdorf <trippels at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-05-01
                 CC|                            |trippels at gcc dot gnu.org
          Component|c                           |tree-optimization
            Summary|ice in vect_is_simple_use_1 |[6 Regression] ice in
                   |with -O3                    |vect_is_simple_use_1 with
                   |                            |-O3
     Ever confirmed|0                           |1

--- Comment #1 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
int *a;
void
foo ()
{
  do
    {
      a[16] = (a[1] ^ a[0]) << 1 | a[1];
      a[17] = (a[0] ^ a[1]) << 1 | a[0];
      a[18] = (a[0] ^ a[1]) << 1 | a[0];
      a[19] = (a[0] ^ a[1]) << 1 | a[0];
      a[20] = (a[0] ^ a[1]) << 1 | a[0];
      a[21] = (a[0] ^ a[1]) << 1 | a[0];
      a[22] = (a[0] ^ a[1]) << 1 | a[0];
      a[23] = (a[20] ^ a[1]) << 1 | a[9];
      a += 8;
    }
  while (1);
}

[Bug tree-optimization/65961] [6 Regression] ice in vect_is_simple_use_1 with -O3

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65961

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mpolacek at gcc dot gnu.org
   Target Milestone|---                         |6.0

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Started with r222514.

[Bug tree-optimization/65961] [6 Regression] ice in vect_is_simple_use_1 with -O3

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65961

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

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

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

[Bug tree-optimization/65961] [6 Regression] ice in vect_is_simple_use_1 with -O3

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65961

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Hmpf, so we have an operand that is both part of a regular SLP node _and_ is
part
of a SLP node that gets its operand built up from scalars.  So obviously
looking at STMT_VINFO_VECTORIZABLE (def-of-op) isn't giving the correct answer
(it depends on context).

I tried to avoid passing down the SLP node to vect_is_simple_use[_1], but that
is what it would take to fix this (well, or reject the SLP build while we
compute
STMT_VINFO_VECTORIZABLE ()).

I have to think more about what refactoring would make sense here.

[Bug tree-optimization/65961] [6 Regression] ice in vect_is_simple_use_1 with -O3

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65961

--- Comment #5 from David Binderman <dcb314 at hotmail dot com> ---
As of trunk 20150520, this bug looks fixed to me.

[Bug tree-optimization/65961] [6 Regression] ice in vect_is_simple_use_1 with -O3

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65961

--- Comment #6 from Richard Biener <rguenth at gcc dot gnu.org> ---
It might be mitigated for the testcase in question but the underlying problem
didn't get fixed.

[Bug tree-optimization/65961] [6 Regression] ice in vect_is_simple_use_1 with -O3

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65961

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Tue Jun  2 07:50:19 2015
New Revision: 224013

URL: https://gcc.gnu.org/viewcvs?rev=224013&root=gcc&view=rev
Log:
2015-06-02  Richard Biener  <rguenther@suse.de>

        PR tree-optimization/65961
        * tree-vect-slp.c (vect_get_and_check_slp_defs): Remove bogus
        check and clarify dump message.
        (vect_build_slp_tree): If all children are built up from scalars
        build up the parent from scalars instead.
        * tree-vect-stmts.c (vect_is_simple_use): Cleanup.

        * gcc.dg/torture/pr65961.c: New testcase.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr65961.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-vect-slp.c
    trunk/gcc/tree-vect-stmts.c

[Bug tree-optimization/65961] [6 Regression] ice in vect_is_simple_use_1 with -O3

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65961

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

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

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.