[Bug target/93570] New: PPC: __builtin_mtfsf does not return a value

[jens.seifert at de dot ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93570

            Bug ID: 93570
           Summary: PPC: __builtin_mtfsf does not return a value
           Product: gcc
           Version: 8.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jens.seifert at de dot ibm.com
  Target Milestone: ---

Documentation says:

double __builtin_mtfsf(const int,double)

Not documented in 8.3.0, but somehow works, nevertheless looks like the
prototype is wrong and should be

void __builtin_mtfsf(const int,double)

double mtfsf(double x)
{
   return __builtin_mtfsf(0xFF,x);
}

returns

flm.C:9:34: error: void value not ignored as it ought to be
    return __builtin_mtfsf(0xFF, x);

Is __builtin_mtfsf returning void ?
Is it safe to use __builtin_mtfsf with 8.3.0 ?