[Bug tree-optimization/97559] New: ICE at -O1 and above on x86_64-pc-linux-gnu: verify_ssa failed

[Bug tree-optimization/97559] New: ICE at -O1 and above on x86_64-pc-linux-gnu: verify_ssa failed

[su at cs dot ucdavis.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97559

            Bug ID: 97559
           Summary: ICE at -O1 and above on x86_64-pc-linux-gnu:
                    verify_ssa failed
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu
  Target Milestone: ---

[566] % gcctk -v
Using built-in specs.
COLLECT_GCC=gcctk
COLLECT_LTO_WRAPPER=/local/suz-local/software/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/11.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-trunk/configure --disable-bootstrap
--prefix=/local/suz-local/software/local/gcc-trunk --enable-languages=c,c++
--disable-werror --enable-multilib --with-system-zlib
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.0.0 20201024 (experimental) [master revision
d0e2ffcca0e:78f21910dde:a29ff9c53a77b6e208350d8c6db0f3e988f61d1f] (GCC) 
[567] % 
[567] % gcctk -O0 -c small.c
[568] % 
[568] % gcctk -O1 -c small.c
small.c: In function ‘e’:
small.c:5:6: error: stmt with wrong VUSE
    5 | void e () {
      |      ^
# VUSE <.MEM_8(D)>
f_9 = a;
expected .MEM_5
during GIMPLE pass: sink
small.c:5:6: internal compiler error: verify_ssa failed
0xf6887b verify_ssa(bool, bool)
        ../../gcc-trunk/gcc/tree-ssa.c:1208
0xbf6e07 execute_function_todo
        ../../gcc-trunk/gcc/passes.c:1999
0xbf7bb2 execute_todo
        ../../gcc-trunk/gcc/passes.c:2046
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.
[569] % 
[569] % cat small.c
int printf (char *, ...);

int a, b, c, d;

void e () {
  int f = a;
  if (b) {
  L1:
    b = 0;
  L2:
    if (c) {
      if (f)
        printf("0");
      goto L1;
    }
  }
  if (d)
    goto L2;
}

[Bug tree-optimization/97559] ICE at -O1 and above on x86_64-pc-linux-gnu: verify_ssa failed

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97559

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|UNCONFIRMED                 |ASSIGNED
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2020-10-26

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
I will have a look.

[Bug tree-optimization/97559] ICE at -O1 and above on x86_64-pc-linux-gnu: verify_ssa failed

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97559

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
OK, so as expected this is

static bool
statement_sink_location (gimple *stmt, basic_block frombb,
                         gimple_stmt_iterator *togsi, bool *zero_uses_p)
{
...
      /* If this is a load then do not sink past any stores.
         Look for virtual definitions in the path from frombb to the sink
         location computed from the real uses and if found, adjust
         that it a common dominator.  */
      if (gimple_vuse (stmt))
        {
...
          FOR_EACH_IMM_USE_FAST (use_p, imm_iter, gimple_vuse (stmt))
            {
...
                  /* In case the PHI node post-dominates the current insert
location
                     we can disregard it.  But make sure it is not dominating
                     it as well as can happen in a CFG cycle.  */
                  if (commondom != bb
                      && !dominated_by_p (CDI_DOMINATORS, commondom, bb)
                      && dominated_by_p (CDI_POST_DOMINATORS, commondom, bb))
                    continue;

where the use stmt is in an irreducible region and thus the dominance
check breaks down.  We want to avoid doing a full 'is use_stmt' on a
path from bb to commondom check and thus are employing some heuristics
to capture most cases.  We do have natural loops computed here and
irreducible regions marked, need to think about an adjustment to the above.

Meanwhile more testcases are always welcome.

[Bug tree-optimization/97559] ICE at -O1 and above on x86_64-pc-linux-gnu: verify_ssa failed

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97559

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |10.2.0
      Known to fail|                            |11.0
                 CC|                            |marxin at gcc dot gnu.org

--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> ---
Btw. started with r11-3705-gdae673abd37d4004.

[Bug tree-optimization/97559] [11 Regression] ICE at -O1 and above on x86_64-pc-linux-gnu: verify_ssa failed

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97559

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|ICE at -O1 and above on     |[11 Regression] ICE at -O1
                   |x86_64-pc-linux-gnu:        |and above on
                   |verify_ssa failed           |x86_64-pc-linux-gnu:
                   |                            |verify_ssa failed
                 CC|                            |jakub at gcc dot gnu.org
           Priority|P3                          |P1
   Target Milestone|---                         |11.0

[Bug tree-optimization/97559] [11 Regression] ICE at -O1 and above on x86_64-pc-linux-gnu: verify_ssa failed

[zhendong.su at inf dot ethz.ch]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97559

Zhendong Su <zhendong.su at inf dot ethz.ch> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |zhendong.su at inf dot ethz.ch

--- Comment #4 from Zhendong Su <zhendong.su at inf dot ethz.ch> ---
Another repro for the same ICE (but only at -Os):

[541] % gcctk -O1 -c small.c
[542] % gcctk -O2 -c small.c
[543] % gcctk -O3 -c small.c
[544] %
[544] % gcctk -Os -c small.c
small.c: In function ‘e’:
small.c:3:6: error: stmt with wrong VUSE
    3 | void e() {
      |      ^
# VUSE <.MEM_7(D)>
f_8 = b;
expected .MEM_5
during GIMPLE pass: sink
small.c:3:6: internal compiler error: verify_ssa failed
0xf707cb verify_ssa(bool, bool)
        ../../gcc-trunk/gcc/tree-ssa.c:1208
0xbfe3e7 execute_function_todo
        ../../gcc-trunk/gcc/passes.c:2046
0xbff192 execute_todo
        ../../gcc-trunk/gcc/passes.c:2093
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.
[545] %
[545] % cat small.c
int a, b, c, d;

void e() {
  int f = b;
  if (a) {
  L1:
    a = 0;
  L2:
    if (a) {
      c = b;
      goto L1;
    }
  }
  if (d)
    goto L2;
}

[Bug tree-optimization/97559] [11 Regression] ICE at -O1 and above on x86_64-pc-linux-gnu: verify_ssa failed

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97559

--- 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:a294e6368f80ac27c5150414027d1cf2a21bd9b7

commit r11-5840-ga294e6368f80ac27c5150414027d1cf2a21bd9b7
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Dec 8 09:45:57 2020 +0100

    tree-optimization/97559 - fix sinking in irreducible regions

    This fixes sinking of loads when irreducible regions are involved
    and the heuristics to find stores on the path along the sink
    breaks down since that uses dominator queries.

    2020-12-08  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/97559
            * tree-ssa-sink.c (statement_sink_location): Never ignore
            PHIs on sink paths in irreducible regions.

            * gcc.dg/torture/pr97559-1.c: New testcase.
            * gcc.dg/torture/pr97559-2.c: Likewise.

[Bug tree-optimization/97559] [11 Regression] ICE at -O1 and above on x86_64-pc-linux-gnu: verify_ssa failed

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97559

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 finally.