[Bug tree-optimization/112357] New: Documentation for vect-max-peeling-for-alignment references -1 but -1 does not work

[Bug tree-optimization/112357] New: Documentation for vect-max-peeling-for-alignment references -1 but -1 does not work

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112357

            Bug ID: 112357
           Summary: Documentation for vect-max-peeling-for-alignment
                    references -1 but -1 does not work
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: documentation
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Using `-O2 --param vect-max-peeling-for-alignment=-1` provides the following
error message:
```
g++: error: argument to '--param=vect-max-peeling-for-alignment=' should be a
non-negative integer
```

But https://gcc.gnu.org/onlinedocs//gcc/Optimize-Options.html documents -1:
```
vect-max-peeling-for-alignment
The maximum number of loop peels to enhance access alignment for vectorizer.
Value -1 means no limit.
```

[Bug tree-optimization/112357] Documentation for vect-max-peeling-for-alignment references -1 but -1 does not work

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112357

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2023-11-03
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
-param=vect-max-peeling-for-alignment=
Common Joined UInteger Var(param_vect_max_peeling_for_alignment) Init(-1)
IntegerRange(0, 64) Param Optimization
Maximum number of loop peels to enhance alignment of data references in a loop.

Interesting that we allow an Init() with an out-of-range value.  Possibly
a way to detect whether the parameter was specified or not ...

Documentation should probably be adjusted to mention when not specified
no limit applies (the limit is the vectorization factor - 1)