On Tue, 15 Feb 2005, Joe Buck wrote: > The problem is that the user can independently set the IEEE rounding mode. > This means that you can only fold floating point constants in cases where > the generated result is exact; you cannot fold 1./3. for example.
You can fold 1./3. unless the user uses the FENV_ACCESS pragma to say you can't in a particular region of the code. (Or -frounding-math while we don't have FENV_ACCESS, although -frounding-math may not work fully either as parts of the compiler may not be aware that the results of apparently identical floating-point computations may depend on the rounding mode.) Even with FENV_ACCESS, for C you still need to fold 1./3. in static initializers (using the default rounding mode in that case). -- Joseph S. Myers http://www.srcf.ucam.org/~jsm28/gcc/ [EMAIL PROTECTED] (personal mail) [EMAIL PROTECTED] (CodeSourcery mail) [EMAIL PROTECTED] (Bugzilla assignments and CCs)
