http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52904
Laurent Rineau <Laurent.Rineau__gcc at normalesup dot org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |Laurent.Rineau__gcc@normale | |sup.org --- Comment #5 from Laurent Rineau <Laurent.Rineau__gcc at normalesup dot org> --- With the following gcc version: gcc (GCC) 4.8.2 20131017 (Red Hat 4.8.2-1) I have a similar result: $ gcc -c -Wstrict-overflow -O2 v.i v.i: In function ‘wait_reading_process_output’: v.i:14:6: warning: assuming signed overflow does not occur when simplifying conditional to constant [-Wstrict-overflow] if (nfds < 0) ^ That diagnostic seems right, according to the documentation of -Wstrict-overflow.