Only add the option processing and store the result. No attributes are
added to FIR yet.
Only the "off" and "fast" options are supported. "fast-honor-pragmas" is not applicable because we do not implement #pragma clang fp contract() in Fortran [1]. "on" is not supported because it is unclear how to fuse only within individual statements. gfortran also does not implement "on": treating it as an "off".
Currently the default value is "off" to preserve existing behavior. gfortran uses "fast" by default and that may be the right thing for flang-new after further discussion in the future, but that can be changed separately. gfortran's documentation is available here.
[1] https://clang.llvm.org/docs/LanguageExtensions.html#extensions-to-specify-floating-point-flags
I still think that we shouldn't be making references to Flang in Clang documentation. And this DocBrief is only used by Clang. Also, "flang" is problematic - what do you mean by "flang"?