http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48823
--- Comment #4 from Jeroen Demeyer <jdemeyer at cage dot ugent.be> 2011-10-13 20:05:21 UTC --- (In reply to comment #3) > The difference in results is due to the use of the fma instructions (fused > multiply add). If you don't want the fma instructions to be used you should > use the -ffp-contract=on flag. Thanks for the reply, I understand your reasoning. However, will this option guarantee strict IEEE floating-point behaviour or are there other flags to be specified? I have always been under the impression that *by default* gcc produced code respecting the floating-point standard unless one specifies something like -ffast-math. It seems this has changed in recent GCC versions.
