[Bug target/86160] Implement isinf on PowerPC

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86160

--- Comment #2 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
Generic (for some floating-point formats, and maybe not for 128-bit 
formats on 32-bit targets) bit-pattern is* were implemented by Tamar 
Christina's patches that had to be reverted as they broke some powerpc 
configurations.  See bug 66462 - when versions based on integer arithmetic 
are available they should be used in place of ones based on floating-point 
arithmetic for -fsignaling-nans, regardless of which is more efficient on 
a given processor, since is* aren't meant to raise "invalid" for signaling 
NaN arguments but all comparisons do.