On Tue, Aug 09, 2005 at 01:35:11PM -0700, Richard Henderson wrote: > On Tue, Aug 09, 2005 at 11:02:22AM -0700, H. J. Lu wrote: > > I have a small testcase to show that enable FTZ/DAZ makes a huge (>160 > > times faster) difference on SSE floating point code. Icc enables it by > > defailt for -ON (N>=1). Should gcc do the same? > > This is the flush-denormals-to-zero bit? >
Yes, FTZ stands for flush to zero and DAZ stands for denormals are zero. > See config/{alpha,ia64,sparc}/crtfastmath.c, and how that gets used. > The one for x86 may be very similar to alpha's crtfastmath.c. It can be used for fast math on SSE targets. H.J.