[Bug tree-optimization/110954] New: [14 Regression] Wrong code with -O0

[Bug tree-optimization/110954] New: [14 Regression] Wrong code with -O0

[vsevolod.livinskiy at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110954

            Bug ID: 110954
           Summary: [14 Regression] Wrong code with -O0
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vsevolod.livinskiy at gmail dot com
  Target Milestone: ---

Link to the compiler explorer:
https://godbolt.org/z/WYoT4hW9v

Reproducer:
#include <stdio.h>
unsigned long long a;
void b(unsigned long long *c, int g) { *c = g; }
int d, e = -38921963;
long f;
int main() {
  d = (-1807546494482798067UL - f < (6033086967267 > 0)) & e |
      !(-1807546494482798067UL - f < (6033086967267 > 0));
  b(&a, d);
  printf("%llu\n", a);
  if (a != 1)
    __builtin_abort();
}

Error:
>$ g++ -O0 test.cpp && ./a.out 
18446744073670629653
Aborted (core dumped)
>$ /usr/bin/g++-11 -O0 test.cpp && ./a.out 
1

gcc version 14.0.0 20230808 (20659be04c2749f9f47b085f1789eee0d145fb36)

[Bug tree-optimization/110954] [14 Regression] Wrong code with -O0

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110954

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-08-09
                 CC|                            |pinskia at gcc dot gnu.org
             Status|UNCONFIRMED                 |ASSIGNED
   Target Milestone|---                         |14.0
     Ever confirmed|0                           |1
           Assignee|unassigned at gcc dot gnu.org      |pinskia at gcc dot gnu.org

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
I think this is mine.

[Bug middle-end/110954] [14 Regression] Wrong code with -O0

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110954

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|tree-optimization           |middle-end

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Generic has different type constraints than gimple and that is what is
confusing here.
bitwise_inverted_equal_p cannot check comparisons to see if they are inverse of
each other unless the type is a boolean type ...

[Bug middle-end/110954] [14 Regression] Wrong code with -O0

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110954

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Cleaned and simplified up testcase:
```
#define comparison (f < 0)
int main() {
  int f = 0;
  int d = comparison | !comparison;
  if (d != 1)
    __builtin_abort();
}

```

[Bug middle-end/110954] [14 Regression] Wrong code with -O0

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110954

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch
                URL|                            |https://gcc.gnu.org/piperma
                   |                            |il/gcc-patches/2023-August/
                   |                            |626896.html

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Patch posted:
https://gcc.gnu.org/pipermail/gcc-patches/2023-August/626896.html

[Bug middle-end/110954] [14 Regression] Wrong code with -O0

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110954

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 55718
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55718&action=edit
new patch which I am testing

The only thing is it is sometimes overly conserative with the check of
`!wascmp || element_precision (type) == 1` for vector types
but that is ok those were not handled before either anyways.

We do handle `a & ~a` and `a |^ ~a` for all cases (correctly) like we did
previously and before r14-2925-g2bae476b511dc441bf61da8a4 .

[Bug middle-end/110954] [14 Regression] Wrong code with -O0

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110954

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Andrew Pinski <pinskia@gcc.gnu.org>:

https://gcc.gnu.org/g:f956c232649e4bb7482786cd54e5d5b4085cd00a

commit r14-3140-gf956c232649e4bb7482786cd54e5d5b4085cd00a
Author: Andrew Pinski <apinski@marvell.com>
Date:   Wed Aug 9 13:49:24 2023 -0700

    Fix PR 110954: wrong code with cmp | !cmp

    This was an oversight on my part forgetting that
    cmp will might have a different true value than all ones
    but will have a value of 1 in most cases.
    This means if we have `(f < 0) | !(f < 0)` we would
    optimize this to -1 rather than just 1.

    This is version 2 of the patch.
    Decided to go down a different route than just checking if
    the precission was 1 inside bitwise_inverted_equal_p.
    So instead bitwise_inverted_equal_p gets passed an argument
    that will be set if there was a comparison that was being compared
    and the user of bitwise_inverted_equal_p decides what needs to be done.
    In most uses of bitwise_inverted_equal_p, the check will be
    `!wascmp || element_precision (type) == 1` .
    But in the case of `a & ~a` and `a ^| ~a` we can handle the case
    of wascmp by using constant_boolean_node isntead.

    OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

            PR tree-optimization/110954

    gcc/ChangeLog:

            * generic-match-head.cc (bitwise_inverted_equal_p): Add
            wascmp argument and set it accordingly.
            * gimple-match-head.cc (bitwise_inverted_equal_p): Add
            wascmp argument to the macro.
            (gimple_bitwise_inverted_equal_p): Add
            wascmp argument and set it accordingly.
            * match.pd (`a & ~a`, `a ^| ~a`): Update call
            to bitwise_inverted_equal_p and handle wascmp case.
            (`(~x | y) & x`, `(~x | y) & x`, `a?~t:t`): Update
            call to bitwise_inverted_equal_p and check to see
            if was !wascmp or if precision was 1.

    gcc/testsuite/ChangeLog:

            * gcc.c-torture/execute/pr110954-1.c: New test.

[Bug middle-end/110954] [14 Regression] Wrong code with -O0

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110954

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jwzeng at nuaa dot edu.cn

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 111007 has been marked as a duplicate of this bug. ***

[Bug middle-end/110954] [14 Regression] Wrong code with -O0

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110954

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

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

--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed.