[Bug tree-optimization/115307] [avr] Don't expand isinf() like a built-in

[gjl at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115307

--- Comment #5 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #1)
> The issue is that we probably fold isinff early.  On x86 I see already in
> .original:
> 
>   return !(ABS_EXPR <f> u<= 3.4028234663852885981170418348451692544e+38);

That looks incorrect.  The man 3 page for isinf states that it returns -1 for
-Inf, but that expression returns 1 for -Inf (same for the expanded avr code
above).