tree c14fb2a3d3fc0492034c7742b5e1118e9bf8ccd0
parent e4dd65305a046019123ab34ebdcbe761a3a719ca
author Rich Felker <dalias@aerifal.cx> 1555800780 -0400
committer Rich Felker <dalias@aerifal.cx> 1555800905 -0400

make new math code compatible with unused variable warning/error

commit b50d315fd23f0fbc4c11e2583801dd123d933745 introduced
fp_force_eval implemented by default with a dead store to a volatile
variable. unfortunately introduces warnings with -Wunused-variable and
breaks the ability to use -Werror with the default warning options set
by configure when warnings are enabled.

we could just call fp_barrier instead, but that results in a spurious
load after the store due to volatile semantics.

the fix committed here avoids the load. it will still produce warnings
without -Wno-unused-but-set-variable, but that's part of our default
warning profile, and there are already other locations in the source
where an unused variable warning will occur without it.