[Bug c/115023] New: __builtin_assoc_barrier does not talk about contracting even though it prevents it too

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115023

            Bug ID: 115023
           Summary: __builtin_assoc_barrier does not talk about
                    contracting even though it prevents it too
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Keywords: documentation
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

Take:
```
float foo(float a, float b, float c) {
  return __builtin_assoc_barrier(a * b) + c;
}
```
On aarch64 (or on x86_64 with -mfma), this will prevent the generation of FMA
but the documentation does not mention that even though this is by design.