[Bug c/98393] New: new valgrind error for ./gcc.target/m68k/pr52573.c

[Bug c/98393] New: new valgrind error for ./gcc.target/m68k/pr52573.c

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

            Bug ID: 98393
           Summary: new valgrind error for ./gcc.target/m68k/pr52573.c
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dcb314 at hotmail dot com
  Target Milestone: ---

A valgrind version of gcc trunk dated 20201206, with hash 8c23434fdadcf4ca,
compiles testsuite file ./gcc.target/m68k/pr52573.c fine with compiler flag -O3
on x86_64.

A week later, gcc trunk dated 20201211, with hash 97b56dece7413839, does this:

==11710== Conditional jump or move depends on uninitialised value(s)
==11710==    at 0xE9DC54: vect_build_slp_instance(vec_info*, slp_instance_kind,
vec<_stmt_vec_info*, va_heap, vl_p
tr>&, _stmt_vec_info*, unsigned int, unsigned int*, hash_map<vec<gimple*,
va_heap, vl_ptr>, _slp_tree*, simple_has
hmap_traits<bst_traits, _slp_tree*> >*, _stmt_vec_info*) (tree-vect-slp.c:2396)

The problem remains a week later in gcc trunk dated 20201218.

I will have a look with git bisect.

[Bug c/98393] new valgrind error for ./gcc.target/m68k/pr52573.c

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

--- Comment #1 from David Binderman <dcb314 at hotmail dot com> ---
Trying hash f6e8e2797ebae21e.

[Bug c/98393] new valgrind error for ./gcc.target/m68k/pr52573.c

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

--- Comment #2 from David Binderman <dcb314 at hotmail dot com> ---
Seems good, so range reduces to f6e8e2797ebae21e..97b56dece7413839

Trying 4cf70c20cb10acd6

[Bug c/98393] new valgrind error for ./gcc.target/m68k/pr52573.c

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

--- Comment #3 from David Binderman <dcb314 at hotmail dot com> ---
Seems ok, so range reduces to 4cf70c20cb10acd6..97b56dece7413839

Trying 7f359556a772e26e

[Bug c/98393] new valgrind error for ./gcc.target/m68k/pr52573.c

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

--- Comment #4 from David Binderman <dcb314 at hotmail dot com> ---
Seems good, so range reduces to 7f359556a772e26e..97b56dece7413839

Trying 1423318fa7786493

[Bug c/98393] new valgrind error for ./gcc.target/m68k/pr52573.c

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

--- Comment #5 from David Binderman <dcb314 at hotmail dot com> ---
Range so far seems to be 7f359556a772e26e..1423318fa7786493

Trying fa4a8b6463e0dbc2

[Bug c/98393] new valgrind error for ./gcc.target/m68k/pr52573.c

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

David Binderman <dcb314 at hotmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenther at suse dot de

--- Comment #6 from David Binderman <dcb314 at hotmail dot com> ---
So commit fc7b4248172561a9ee310e2d43d8a485a5c9e108 
appears to be the culprit.

May I ask Richard to confirm my git bisect analysis ?

[Bug tree-optimization/98393] [11 Regression] valgrind error for ./gcc.target/m68k/pr52573.c since r11-5928-gfc7b4248172561a9

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
          Component|c                           |tree-optimization
   Last reconfirmed|                            |2020-12-21
             Status|UNCONFIRMED                 |NEW
      Known to fail|                            |11.0
            Summary|new valgrind error for      |[11 Regression] valgrind
                   |./gcc.target/m68k/pr52573.c |error for
                   |                            |./gcc.target/m68k/pr52573.c
                   |                            |since
                   |                            |r11-5928-gfc7b4248172561a9
      Known to work|                            |10.2.0
                 CC|                            |marxin at gcc dot gnu.org
   Target Milestone|---                         |11.0
            Version|unknown                     |11.0

--- Comment #7 from Martin Liška <marxin at gcc dot gnu.org> ---
Reduced test-case:

$ cat m68.i
struct {
  int : 12, : 11, k : 9;
  long l;
} sH;

int sH_3___trans_tmp_1, sH_3_i, sH_3_v;

unsigned sH_3_s;

void
sH_3() {
  char *p = (char *)&sH;
  sH_3_i = 0;
  for (; sH_3_i < sizeof(sH); ++sH_3_i) {
    sH_3_s *= 515245;
    sH_3___trans_tmp_1 = sH_3_s % 2048;
    *p++ = sH_3___trans_tmp_1;
  }
  sH.k = sH_3_v;
}

$ ./xgcc -B. m68.i -c -O3
/home/marxin/Programming/gcc2/gcc/tree-vect-slp.c:2486:16: runtime error: load
of value 80, which is not a valid value for type 'bool'
    #0 0x2e89cbf in vect_build_slp_instance
/home/marxin/Programming/gcc2/gcc/tree-vect-slp.c:2486
    #1 0x2e8b237 in vect_analyze_slp_instance
/home/marxin/Programming/gcc2/gcc/tree-vect-slp.c:2655
    #2 0x2e8a0a2 in vect_build_slp_instance
/home/marxin/Programming/gcc2/gcc/tree-vect-slp.c:2524
    #3 0x2e8b237 in vect_analyze_slp_instance
/home/marxin/Programming/gcc2/gcc/tree-vect-slp.c:2655
    #4 0x2e8b4e5 in vect_analyze_slp(vec_info*, unsigned int)
/home/marxin/Programming/gcc2/gcc/tree-vect-slp.c:2687
    #5 0x2e9ac0c in vect_slp_analyze_bb_1
/home/marxin/Programming/gcc2/gcc/tree-vect-slp.c:4507
    #6 0x2e9b968 in vect_slp_region
/home/marxin/Programming/gcc2/gcc/tree-vect-slp.c:4619
    #7 0x2e9d7d1 in vect_slp_bbs
/home/marxin/Programming/gcc2/gcc/tree-vect-slp.c:4767
    #8 0x2e9e167 in vect_slp_function(function*)
/home/marxin/Programming/gcc2/gcc/tree-vect-slp.c:4853
    #9 0x2ee0503 in execute
/home/marxin/Programming/gcc2/gcc/tree-vectorizer.c:1449
    #10 0x200b8a1 in execute_one_pass(opt_pass*)
/home/marxin/Programming/gcc2/gcc/passes.c:2567
    #11 0x200c229 in execute_pass_list_1
/home/marxin/Programming/gcc2/gcc/passes.c:2656
    #12 0x200c2de in execute_pass_list_1
/home/marxin/Programming/gcc2/gcc/passes.c:2657
    #13 0x200c2de in execute_pass_list_1
/home/marxin/Programming/gcc2/gcc/passes.c:2657
    #14 0x200c37c in execute_pass_list(function*, opt_pass*)
/home/marxin/Programming/gcc2/gcc/passes.c:2667
    #15 0x10e5be7 in cgraph_node::expand()
/home/marxin/Programming/gcc2/gcc/cgraphunit.c:1829
    #16 0x10e753f in expand_all_functions
/home/marxin/Programming/gcc2/gcc/cgraphunit.c:1997
    #17 0x10e9669 in symbol_table::compile()
/home/marxin/Programming/gcc2/gcc/cgraphunit.c:2361
    #18 0x10e9ff6 in symbol_table::finalize_compilation_unit()
/home/marxin/Programming/gcc2/gcc/cgraphunit.c:2542
    #19 0x249ec80 in compile_file
/home/marxin/Programming/gcc2/gcc/toplev.c:482
    #20 0x24a74c3 in do_compile /home/marxin/Programming/gcc2/gcc/toplev.c:2193
    #21 0x24a7ac6 in toplev::main(int, char**)
/home/marxin/Programming/gcc2/gcc/toplev.c:2332
    #22 0x5146fda in main /home/marxin/Programming/gcc2/gcc/main.c:39
    #23 0x7ffff6d2a151 in __libc_start_main (/lib64/libc.so.6+0x28151)
    #24 0xa0ba2d in _start (/dev/shm/objdir2/gcc/cc1+0xa0ba2d)

And yes, it started with r11-5928-gfc7b4248172561a9.

[Bug tree-optimization/98393] [11 Regression] valgrind error for ./gcc.target/m68k/pr52573.c since r11-5928-gfc7b4248172561a9

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

--- Comment #8 from Martin Liška <marxin at gcc dot gnu.org> ---
Happens when:

(gdb) p node
$4 = (slp_tree) 0x0

[Bug tree-optimization/98393] [11 Regression] valgrind error for ./gcc.target/m68k/pr52573.c since r11-5928-gfc7b4248172561a9

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

--- Comment #9 from David Binderman <dcb314 at hotmail dot com> ---
Also from the testsuite, files 

./gcc.c-torture/execute/20040709-1.c
./gcc.dg/torture/pr98235.c
./gcc.dg/tree-ssa/loop-34.c

with -O3 show the same problem.

[Bug tree-optimization/98393] [11 Regression] valgrind error for ./gcc.target/m68k/pr52573.c since r11-5928-gfc7b4248172561a9

[dcb314 at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

--- Comment #10 from David Binderman <dcb314 at hotmail dot com> ---
Reduced test case:

typedef struct {
  short a;
  struct {
    unsigned short b;
    unsigned short c
  } d[]
} e;
enum { f, g, h, i };
e j;
char k, l;
e *m;
void n(void) {
  int o;
  char *q, *r = 0, *s, *t, *p = &k;
  for (; *p; ++p)
    switch (o) {
    case f:
      o = s = p;
    case g:
      switch (*p) {
      case '@':
        t = p;
        o = h;
      }
      break;
    case h:
      q = p;
    case i:
      if (p == '#')
        r = p;
    }
  j.d[0].b = q - &k;
  j.d[0].c = r - q;
  if (s) {
    j.d[0].b = s - &k;
    j.d[0].c = t - s;
  }
  if (m)
    j.d[0].b = j.d[0].c = l;
}

[Bug tree-optimization/98393] [11 Regression] valgrind error for ./gcc.target/m68k/pr52573.c since r11-5928-gfc7b4248172561a9

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

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
           Priority|P3                          |P1

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
Mine.  Looks like PR98270 but here we have more info.

[Bug tree-optimization/98393] [11 Regression] valgrind error for ./gcc.target/m68k/pr52573.c since r11-5928-gfc7b4248172561a9

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

--- Comment #12 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:0926259f9fc21a7f1e09f45f8aede156ef249585

commit r11-6437-g0926259f9fc21a7f1e09f45f8aede156ef249585
Author: Richard Biener <rguenther@suse.de>
Date:   Mon Jan 4 11:22:24 2021 +0100

    tree-optimization/98393 - properly init matches when failing SLP

    This zeroes matches when failing SLP discovery because of the
    work limit.

    2021-01-04  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/98393
            * tree-vect-slp.c (vect_build_slp_tree): Properly zero matches
            when hitting the limit.

[Bug tree-optimization/98393] [11 Regression] valgrind error for ./gcc.target/m68k/pr52573.c since r11-5928-gfc7b4248172561a9

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

--- Comment #13 from Richard Biener <rguenth at gcc dot gnu.org> ---
*** Bug 98270 has been marked as a duplicate of this bug. ***

[Bug tree-optimization/98393] [11 Regression] valgrind error for ./gcc.target/m68k/pr52573.c since r11-5928-gfc7b4248172561a9

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98393

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

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

--- Comment #14 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.