[Bug middle-end/111959] New: tree_single_nonnegative_warnv_p could use tree_nonzero_bits for SSA_NAMES and int types

[Bug middle-end/111959] New: tree_single_nonnegative_warnv_p could use tree_nonzero_bits for SSA_NAMES and int types

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111959

            Bug ID: 111959
           Summary: tree_single_nonnegative_warnv_p could use
                    tree_nonzero_bits for SSA_NAMES and int types
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: internal-improvement, missed-optimization
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

I Noticed this while looking into PR 101590.

tree_single_nonnegative_warnv_p  currently does:
    case SSA_NAME:
      /* Limit the depth of recursion to avoid quadratic behavior.
         This is expected to catch almost all occurrences in practice.
         If this code misses important cases that unbounded recursion
         would not, passes that need this information could be revised
         to provide it through dataflow propagation.  */
      return (!name_registered_for_update_p (t)
              && depth < param_max_ssa_name_query_depth
              && gimple_stmt_nonnegative_warnv_p (SSA_NAME_DEF_STMT (t),
                                                  strict_overflow_p, depth));

But we could/should use tree_nonzero_bits first to see if the info is already
cached somewhere.  This might speed up things.

An example of where this would improve is:
```
int f(int a, int b)
{
  if (a & ~0xff) __builtin_unreachable();
  return a / (1<<b);
}
int f1(int a, int b)
{
  if (a & ~0xff) __builtin_unreachable();
  return a >>b;
}
```

There are other examples too.

[Bug middle-end/111959] tree_single_nonnegative_warnv_p could use tree_nonzero_bits for SSA_NAMES and int types

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111959

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2023-10-24
             Status|UNCONFIRMED                 |NEW
           Assignee|unassigned at gcc dot gnu.org      |pinskia at gcc dot gnu.org

[Bug middle-end/111959] tree_single_nonnegative_warnv_p could use tree_nonzero_bits for SSA_NAMES and int types

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111959

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Floating point could also use the ranger too.
I do wonder if we want to use the global or local ranger here ...
I am going to start with the global one.

[Bug middle-end/111959] tree_single_nonnegative_warnv_p could use tree_nonzero_bits for SSA_NAMES and int types

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111959

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 56195
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56195&action=edit
Patch which I am testing

[Bug middle-end/111959] tree_single_nonnegative_warnv_p could use tree_nonzero_bits for SSA_NAMES and int types

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111959

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=80776

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Doing this causes PR 80776 to show up again.

[Bug middle-end/111959] tree_single_nonnegative_warnv_p could use tree_nonzero_bits for SSA_NAMES and int types

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111959

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch
                URL|                            |https://gcc.gnu.org/piperma
                   |                            |il/gcc-patches/2023-October
                   |                            |/634205.html

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Patch submitted:
https://gcc.gnu.org/pipermail/gcc-patches/2023-October/634205.html