https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113365
--- Comment #4 from newbie-02 <newbie-02 at gmx dot de> --- hello @Andrew Pinski, just if I'm allowed to add one more point / question: using the testing program, playing with optimization, I get the following results for binary64s ( doubles ): unoptimized: time: result: calculation: 0.005571; 4.940656458412465442E-324; x2d = nextafter( 1E-323, 0.0 ) 0.002029; 4.940656458412465442E-324; x2d = ( ( 1E-323 ) - 5E-324 ) 0.005395; 1.482196937523739633E-323; x2d = nextafter( 1E-323, 1.0 ) 0.002023; 1.482196937523739633E-323; x2d = ( ( 1E-323 ) + 5E-324 ) which points out that addition / subtraction are faster in denormals, or assignd at compile time despite x2d is defined volatile. optimized ( compiled with -O2 ): I mostly! get understandable results, ( nextafter similar and ADD / SUB faster reg, compiler cheating?, but on some occasions ( ~10% of compile attempts ): time: result: calculation: 0.009311; 4.940656458412465442E-324; x2d = nextafter( 1E-323, 0.0 ) 0.000420; 4.940656458412465442E-324; x2d = ( ( 1E-323 ) - 5E-324 ) 0.009668; 1.482196937523739633E-323; x2d = nextafter( 1E-323, 1.0 ) 0.000423; 1.482196937523739633E-323; x2d = ( ( 1E-323 ) + 5E-324 ) which has ** ~doubled execution time for nextafters **. Is that something I should worry about? Somthing which could be improved? Either here by options or in gcc?
