------- Comment #4 from rguenth at gcc dot gnu dot org 2009-12-15 13:15 ------- This is because (quoting http://gcc.gnu.org/gcc-4.5/changes.html):
"GCC now supports handling floating-point excess precision arising from use of the x87 floating-point unit in a way that conforms to ISO C99. This is enabled with -fexcess-precision=standard and with standards conformance options such as -std=c99, and may be disabled using -fexcess-precision=fast." GCC with -std=c99 makes sure to properly handle the i387 FPU excess precision. With -fexcess-precision=fast the code is as fast (and non-conforming) like with GCC 4.4. Using -std=gnu99 is also an option. -- rguenth at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jsm28 at gcc dot gnu dot org Status|UNCONFIRMED |RESOLVED Resolution| |WONTFIX Summary|[4.5] Performance regression|[4.5 Regression] Performance |of generated code |regression of generated code Target Milestone|--- |4.5.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42376