The conditions described by POSIX can never happen with IEEE-754 floats.
When the function is const we can emit a single sse4.1 instruction for
it, without losing anything :)
llvm-svn: 162379
There were missed optimizations when the system headers didn't have attributes
in place, specifically:
- Add copysign, exp2, log2, nearbyint, rint and trunc to the list.
These are functions that get inlined by LLVM's optimizer, but only when they
have the right attributes.
- Mark copysign, fabs, fmax, fmin and trunc const unconditionally.
Previously these were only const with -fno-math-errno, but they never set
errno per POSIX.
For ceil/floor/nearbyint/round I'm not aware of any implementation that sets
errno, but POSIX says it may signal overflow so I left them alone for now.
llvm-svn: 162375