[Bug c++/113373] New: ice in verify_ssa

[Bug c++/113373] New: ice in verify_ssa

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113373

            Bug ID: 113373
           Summary: ice in verify_ssa
           Product: gcc
           Version: 14.0
            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 57069
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57069&action=edit
C++ source code

Still some fallout from recent gcc trunk changes.

The attached code does this:

foundBugs $ /home/dcb38/gcc/results.20231221.asan.ubsan/bin/g++ -c -w -O3
-march=znver3 bug996.cc
foundBugs $ /home/dcb38/gcc/results.20231227.asan.ubsan/bin/g++ -c -w -O3
-march=znver3 bug996.cc
../sdk/angelscript/source/as_restore.cpp: In member function ‘void
asCReader::TranslateFunction(asCScriptFunction*)’:
../sdk/angelscript/source/as_restore.cpp:2824:6: error: definition in block 453
does not dominate use in block 457
for SSA_NAME: _1244 in statement:
size_1336 = PHI <_1244(457), 0(227)>
PHI argument
_1244
for PHI node
size_1336 = PHI <_1244(457), 0(227)>
during GIMPLE pass: vect
../sdk/angelscript/source/as_restore.cpp:2824:6: internal compiler error:
verify_ssa failed

[Bug tree-optimization/113373] [14 regression] ICE in verify_ssa

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113373

--- Comment #1 from David Binderman <dcb314 at hotmail dot com> ---
$  /home/dcb38/gcc/results.20231221.asan.ubsan/bin/g++  -v 2>&1 | grep exp
gcc version 14.0.0 20231221 (experimental) (514ea1df444ca7f6) 
$  /home/dcb38/gcc/results.20231227.asan.ubsan/bin/g++  -v 2>&1 | grep expgcc
version 14.0.0 20231227 (experimental) (f19ceb2d49afdfa5) 
$ git log 514ea1df444ca7f6..f19ceb2d49afdfa5 | grep -c "^commit"
83
$

[Bug tree-optimization/113373] [14 regression] ICE in verify_ssa

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113373

--- Comment #2 from David Binderman <dcb314 at hotmail dot com> ---
Reducing ...

[Bug tree-optimization/113373] [14 regression] ICE in verify_ssa

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113373

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0
           Keywords|                            |ice-on-valid-code

[Bug tree-optimization/113373] [14 regression] ICE in verify_ssa

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113373

--- Comment #3 from David Binderman <dcb314 at hotmail dot com> ---
Reduced C++ code seems to be:

void __assert_fail(char *, char *, int, const char *)
    __attribute__((__noreturn__));
template <class T> struct asCArray {
  asCArray(int);
  T &operator[](unsigned);
  T *array;
  int length;
};
template <class T> T &asCArray<T>::operator[](unsigned index) {
  index < length ? void() : __assert_fail("", "", 8, __PRETTY_FUNCTION__);
  return array[index];
}
unsigned asCReaderTranslateFunction_bc_1;
int asCReaderTranslateFunction_bcLength;
void asCReaderTranslateFunction() {
  asCArray<unsigned> bcSizes(asCReaderTranslateFunction_bcLength);
  int offset, size;
  for (int num; offset--; num++)
    size += bcSizes[num];
  asCReaderTranslateFunction_bc_1 = size;
}

[Bug tree-optimization/113373] [14 regression] ICE in verify_ssa

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113373

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 57076
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57076&action=edit
Reduced C testcase

[Bug tree-optimization/113373] [14 regression] ICE in verify_ssa

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113373

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2024-01-13
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.

[Bug tree-optimization/113373] [14 regression] ICE in verify_ssa

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113373

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

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

[Bug tree-optimization/113373] [14 regression] ICE in verify_ssa since r14-6822

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113373

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org
            Summary|[14 regression] ICE in      |[14 regression] ICE in
                   |verify_ssa                  |verify_ssa since r14-6822

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Started with r14-6822-g01f4251b8775c832a92d55e2df57c9ac72eaceef

[Bug tree-optimization/113373] [14 regression] ICE in verify_ssa since r14-6822

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113373

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 #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
All good after vect_do_peeling.  It's wrecked by
vect_create_epilog_for_reduction here:

          scalar_result = scalar_results[k];
          FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, orig_name)
            {
              FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
                SET_USE (use_p, scalar_result);
              update_stmt (use_stmt);

we have two reduction epilogues, one for the early and one for the late
exit but we mismatch the scalar use to replace.

We're also picking up a reduction that's only live on one edge on the other
(but that doesn't seem to result in a problem here).

It also seems we're doing epilogue code generation before creating some
exit PHIs required for that - vect_do_peeling fails to do that.

We can try to hack around that a bit, but there's more issues with this
testcase, like we generate useless epilogues - it seems we should
identify the scalar exit PHI to transform when calling epilogue generation
for a specific edge and skip if there isn't one.

[Bug tree-optimization/113373] [14 regression] ICE in verify_ssa since r14-6822

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113373

--- Comment #8 from GCC 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:86f3cbdaa6f60eaff1cdb4ab2f1a9bc796b67207

commit r14-8330-g86f3cbdaa6f60eaff1cdb4ab2f1a9bc796b67207
Author: Richard Biener <rguenther@suse.de>
Date:   Fri Jan 19 13:55:09 2024 +0100

    tree-optimization/113373 - add missing LC PHIs for live operations

    The following makes reduction epilogue code generation happy by properly
    adding LC PHIs to the exit blocks for multiple exit vectorized loops.

    Some refactoring might make the flow easier to follow but I've refrained
    from doing that with this patch.

    I've kept some fixes in reduction epilogue generation from the earlier
    attempt fixing this PR.

            PR tree-optimization/113373
            * tree-vect-loop-manip.cc (slpeel_tree_duplicate_loop_to_edge_cfg):
            Create LC PHIs in the exit blocks where necessary.
            * tree-vect-loop.cc (vectorizable_live_operation): Do not try
            to handle missing LC PHIs.
            (find_connected_edge): Remove.
            (vect_create_epilog_for_reduction): Cleanup use of auto_vec.

            * gcc.dg/vect/vect-early-break_104-pr113373.c: New testcase.

[Bug tree-optimization/113373] [14 regression] ICE in verify_ssa since r14-6822

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113373

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

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

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.