From: khan AT xraylith DOT wisc DOT edu (Mumit Khan) Subject: Re: double != long double 18 Jan 1999 19:54:21 -0800 Message-ID: <199901190332.VAA22022.cygnus.cygwin32.developers@modi.xraylith.wisc.edu> References: <19990118181646 DOT 34633 AT cygnus DOT com> To: Geoffrey Noer Cc: DJ Delorie , jeffdb AT goodnet DOT com, cygwin32-developers AT cygnus DOT com Geoffrey Noer writes: > On Tue, Jan 12, 1999 at 10:51:40AM -0500, DJ Delorie wrote: > > > > > Why is gcc not consistent with the "HOST" > > > compiler in this area? > > > > I don't know, but remember that the x86 support for gcc isn't limited > > to cygwin - it supports many other x86 targets like djgpp, linux, SCO, > > etc. > > I would think that gcc should be consistent with VC++ in the way that > was suggested. Couldn't this be set in a Cygwin- and Mingw-target > specific x86 config file? Actually, it affects all the x86 platforms, it's just a question of to what degree. There's been quite a bit of discussion regarding this in egcs group. My current fix (local, haven't submitted yet) is to change the rounding mode to MSVC/Intel-VTune compatible mode; if you want to go to extended fp mode, you specify -mextended-fp (or a similarly named switch, can't remember offhand) that simply links in a .o file that changes the mode via GCC's __attribute__((constructor)) mechanism. Interix on the other has solved in a much more general way that applies to *all* x86 ports, and I'm currently working with Donn Terry to get these changes into egcs. For those of who follow egcs list, you've already seen all the discussion. I'm dismayed at the fact that people keep on telling me that it's wrong to expect proper numerical results from x86 and so on. I get expected results from a host of other compilers on this very platform. For those interested, please check out following threads: "x86 regression: optimizer bug in 1.1 and dev" http://www.cygnus.com/ml/egcs-bugs/1998-Nov/0269.html and, "Floating-point Consistency, -ffloat-store, and x86 (mostly)" http://www.cygnus.com/ml/egcs/1998-Dec/0049.html Regards, Mumit