On Thu, Jun 4, 2009 at 10:49 PM, Joseph S. Myers <jos...@codesourcery.com> wrote: > On Thu, 4 Jun 2009, Adam Nemet wrote: > >> 1. Change STRIP_NOPS not to remove the cast if it's changing the precision >> (not just when it changes machine modes). And then audit code quality where >> we need to and are allowed to look through these casts. > > As I said in <http://gcc.gnu.org/ml/gcc-bugs/2007-03/msg02228.html> and > <http://gcc.gnu.org/ml/gcc/2008-01/msg00215.html>, I think such references > to the mode are as a proxy for precision and machine modes are an > inappropriate level of abstraction for the tree optimizers. So I favour > checking for precision here - but I also favour having a good look at > anything using STRIP_NOPS etc. and considering whether it should use some > better defined function for removing redundant conversions instead.
FWIW I agree. STRIP_NOPS should not change the precision - we came to this conclusion multiple times but never got around to do the change. Richard. > -- > Joseph S. Myers > jos...@codesourcery.com >
