[Bug tree-optimization/101541] New: Missing ABSU detection at gimple

[Bug tree-optimization/101541] New: Missing ABSU detection at gimple

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101541

            Bug ID: 101541
           Summary: Missing ABSU detection at gimple
           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: ---

While looking at PR 44608 and finding it was already fixed, I noticed instead
we should produce ABSU at the gimple level but don't currently.

Take:
unsigned abssat2 (int x)
{
    unsigned int y = x;

    if (x < 0)
        y = -y;

  return y;
}

[Bug tree-optimization/101541] Missing ABSU detection at gimple

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101541

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2021-07-21

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.

[Bug tree-optimization/101541] Missing ABSU detection at gimple

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101541

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |pinskia at gcc dot gnu.org
             Status|NEW                         |ASSIGNED

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Mine, let me try to figure out the best way to fix this.

[Bug tree-optimization/101541] Missing ABSU detection at gimple

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101541

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> Mine, let me try to figure out the best way to fix this.

Basically the patterns starting with:
/* abs/negative simplifications moved from fold_cond_expr_with_comparison,
   Need to handle (A - B) case as fold_cond_expr_with_comparison does.
   Need to handle UN* comparisons.

need to add nop_convertN? handling. There is 6 patterns.

[Bug tree-optimization/101541] Missing ABSU detection at gimple

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101541

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Another one missed:
```
unsigned abssat2 (unsigned x)
{
    int y = x;

    if (y < 0)
        x = -x;

  return x;
}
```

I have a patch for the this case, I think. Working on the other case now.

[Bug tree-optimization/101541] Missing ABSU detection at gimple

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101541

--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Actually using bitwise_equal_p makes this easier and no need for the
nop_convert ...

I have a patch where I just need to add testcases too.

[Bug tree-optimization/101541] Missing ABSU detection at gimple

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101541

--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 56116
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56116&action=edit
Patch which I am testing

[Bug tree-optimization/101541] Missing ABSU detection at gimple

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101541

--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Created attachment 56118
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56118&action=edit
Patch which I am testing which allows for more (independent of the other)

This patch improves the case where we have a conversion at the end (after the
negate expression). And with both of these patches together we are able to
catch almost all.

There is one more phi-opt patch needed to catch the case where the conversion
before the negate expression is conditional but that is for another day.

[Bug tree-optimization/101541] Missing ABSU detection at gimple

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101541

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                URL|                            |https://gcc.gnu.org/piperma
                   |                            |il/gcc-patches/2023-October
                   |                            |/633043.html
           Keywords|                            |patch

--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Patch:
https://gcc.gnu.org/pipermail/gcc-patches/2023-October/633043.html

[Bug tree-optimization/101541] Missing ABSU detection at gimple

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101541

--- Comment #9 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:c7609acb8a8210188d21b2cd72ecc6d3b2de2ab8

commit r14-4662-gc7609acb8a8210188d21b2cd72ecc6d3b2de2ab8
Author: Andrew Pinski <pinskia@gmail.com>
Date:   Sun Oct 15 10:36:56 2023 -0700

    MATCH: Improve `A CMP 0 ? A : -A` set of patterns to use bitwise_equal_p.

    This improves the `A CMP 0 ? A : -A` set of match patterns to use
    bitwise_equal_p which allows an nop cast between signed and unsigned.
    This allows catching a few extra cases which were not being caught before.

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

    gcc/ChangeLog:

            PR tree-optimization/101541
            * match.pd (A CMP 0 ? A : -A): Improve
            using bitwise_equal_p.

    gcc/testsuite/ChangeLog:

            PR tree-optimization/101541
            * gcc.dg/tree-ssa/phi-opt-36.c: New test.
            * gcc.dg/tree-ssa/phi-opt-37.c: New test.

[Bug tree-optimization/101541] Missing ABSU detection at gimple

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101541

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|---                         |14.0

--- Comment #10 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Fixed.

[Bug tree-optimization/101541] Missing ABSU detection at gimple

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101541

--- Comment #11 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:0fc13e8c0e39c51e82deb93f324d9d86ad8d7460

commit r14-4889-g0fc13e8c0e39c51e82deb93f324d9d86ad8d7460
Author: Andrew Pinski <pinskia@gmail.com>
Date:   Sun Oct 15 19:15:38 2023 +0000

    Improve factor_out_conditional_operation for conversions and constants

    In the case of a NOP conversion (precisions of the 2 types are equal),
    factoring out the conversion can be done even if int_fits_type_p returns
    false and even when the conversion is defined by a statement inside the
    conditional. Since it is a NOP conversion there is no zero/sign extending
    happening which is why it is ok to be done here; we were trying to prevent
    an extra sign/zero extend from being moved away from definition which no-op
    conversions are not.

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

    gcc/ChangeLog:

            PR tree-optimization/104376
            PR tree-optimization/101541
            * tree-ssa-phiopt.cc (factor_out_conditional_operation):
            Allow nop conversions even if it is defined by a statement
            inside the conditional.

    gcc/testsuite/ChangeLog:

            PR tree-optimization/101541
            * gcc.dg/tree-ssa/phi-opt-39.c: New test.