[Bug target/13899] New: [x86] -mfpmath misdocumented

["bangerth at dealii dot org" <gcc-bugzilla@gcc.gnu.org>]

-mfpmath=X takes an argument X indicating what floating point 
units to use. The manual in invoke.texi lists these choices: 
---------------- 
@item -mfpmath=@var{unit} 
@opindex march 
generate floating point arithmetics for selected unit @var{unit}.  the choices 
for @var{unit} are: 
 
@table @samp 
@item 387 
Use the standard 387 floating point coprocessor present majority of chips and 
emulated otherwise.  Code compiled with this option will run almost 
everywhere. 
The temporary results are computed in 80bit precision instead of precision 
specified by the type resulting in slightly different results compared to most 
of other chips. See @option{-ffloat-store} for more detailed description. 
 
This is the default choice for i386 compiler. 
 
@item sse 
.... 
@item pni 
Use all SSE extensions enabled by @option{-msse2} as well as the new 
SSE extensions in Prescott New Instructions. @option{-mpni} also 
enables 2 builtin functions, @code{__builtin_ia32_monitor} and 
@code{__builtin_ia32_mwait}, for new instructions @code{monitor} and 
@code{mwait}. 
 
@item sse,387 
.... 
@end table 
 
However, compiling any program with -mfpmath=pni on any branch I 
have gives me this: 
g/x> /home/bangerth/bin/gcc-3.5-pre/bin/c++ -march=pentium4 -mfpmath=pni -c 
x.cc 
x.cc:0: error: bad value (pni) for -mfpmath= switch 
 
If this value is really not allowed, then it should be fixed on 
all active branches in the manual. If it is allowed, then the 
bug is somewhere in the option handling. 
 
W.

-- 
           Summary: [x86] -mfpmath misdocumented
           Product: gcc
           Version: 3.3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: bangerth at dealii dot org
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13899