On Wed, Mar 14, 2012 at 11:22 AM, Michael Goffioul <michael.goffi...@gmail.com> wrote: > On Wed, Mar 14, 2012 at 9:48 AM, Bruno Haible <br...@clisp.org> wrote: >> Michael Goffioul wrote: >>> I encountered a compilation error with MSVC when compiling floor.c in >>> strict floating-point mode (-fp:strict). >> >> Note that the use of -fp:strict also leads to test failures such as >> >> test-hypot.h:41: assertion failed >> FAIL: test-hypotl.exe >> >> MSVC appears to compile the test code (test-hypotl.c) in a different way, >> in such a way that a comparison of +Inf with +Inf fails. >> >> I'm therefore not sure this option can be recommended. > > Initially I didn't use it, until I noticed a test failure in octave. > At some point, 2 complex numbers are compared with '<': in octave, > this is implemented by comparing the modules, then the arguments. > However, the result of b < a was true while a and b were the same. > This boiled down to rounding error accumulation in the FPU and the > only way to avoid it was to use -fp:strict. According to MSVC > documentation, this is the only way to get IEEE compliance > (http://msdn.microsoft.com/en-us/library/ms235601(v=vs.100).aspx) and > this is required in a software like octave.
MSVC is broken for floating point comparaison see for instance https://connect.microsoft.com/VisualStudio/feedback/details/518015/nan-comparison-under-the-64-bit-compiler-is-incorrect > Michael. >
