[Bug tree-optimization/107053] New: ones bits is not tracked and popcount is not tracked

[Bug tree-optimization/107053] New: ones bits is not tracked and popcount is not tracked

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107053

            Bug ID: 107053
           Summary: ones bits is not tracked and popcount is not tracked
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Take:
```
void link_failure();
void f(int a)
{
    a |= 0x300;
    int b =  __builtin_popcount(a);
    if (b < 3)
        link_failure();
}
```
The if statement should be optimized away.
The reason is after the |, at least 3 bits are set in a.

[Bug tree-optimization/107053] ones bits is not tracked and popcount is not tracked

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107053

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
This testcase is not optimized by clang/llvm.

[Bug tree-optimization/107053] ones bits is not tracked and popcount is not tracked

[aldyh at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107053

Aldy Hernandez <aldyh at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2022-09-27

[Bug tree-optimization/107053] ones bits is not tracked and popcount is not tracked

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107053

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note the correct testcase is:
void link_failure();
void f(int a)
{
    a |= 0x300;
    int b =  __builtin_popcount(a);
    if (b < 2)
        link_failure();
}

--- CUT ---
the range of b should be 2..31 (assuming int is 32bits).
With this change clang is able to optimize it.

For the original testcase I think it can be folded to:
void link_failure();
void f(int a)
{
    int a1 &= ~0x300;
    if (a1 != 0)
        link_failure();
}
but that might be worse unless popcount can be removed. (If I did this
correctly).

[Bug tree-optimization/107053] ones bits is not tracked and popcount is not tracked

[aldyh at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107053

Aldy Hernandez <aldyh at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=107043
                 CC|                            |amacleod at redhat dot com

--- Comment #3 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
This is a variant of PR107043 which I discuss in comment #3.  We can't get this
because we don't track the or-mask, the known 1-bits.

[Bug tree-optimization/107053] ones bits is not tracked and popcount is not tracked

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107053

--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Aldy Hernandez <aldyh@gcc.gnu.org>:

https://gcc.gnu.org/g:137fb7077f7711e2e09ee8f82650fe7d93de6a4d

commit r14-2479-g137fb7077f7711e2e09ee8f82650fe7d93de6a4d
Author: Aldy Hernandez <aldyh@redhat.com>
Date:   Fri Jun 30 20:40:02 2023 +0200

    [range-op] Take known set bits into account in popcount [PR107053]

    This patch teaches popcount about known set bits which are now
    available in the irange.

            PR tree-optimization/107053

    gcc/ChangeLog:

            * gimple-range-op.cc (cfn_popcount): Use known set bits.

    gcc/testsuite/ChangeLog:

            * gcc.dg/tree-ssa/pr107053.c: New test.

[Bug tree-optimization/107053] ones bits is not tracked and popcount is not tracked

[aldyh at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107053

Aldy Hernandez <aldyh at gcc dot gnu.org> changed:

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

--- Comment #5 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
fixed in trunk

[Bug tree-optimization/107053] ones bits is not tracked and popcount is not tracked

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107053

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0