Clang as default compiler November 4th

[Steve Kargl]

On Tue, Sep 11, 2012 at 04:27:55PM +0200, Tijl Coosemans wrote:
> On 11-09-2012 16:10, Dimitry Andric wrote:
> > On 2012-09-11 15:24, Steve Kargl wrote:
> >> What is important is whether software built with clang functions
> >> correctly.  See for example,
> >>
> >> http://math-atlas.sourceforge.net/errata.html#WhatComp
> > 
> > Yes, maths support, specifically precision, is admittedly still one of
> > clang's (really llvm's) weaker points.  It is currently not really a
> > high priority item for upstream.
> > 
> > This is obviously something that a certain part of our userbase will
> > care a lot about, while most of the time they won't care so much about
> > licensing or politics.  So those people are probably better off using
> > gcc for the time being.
> 
> Does it affect the accuracy of libm functions?
> 

I'm not sure if anyone has done any extensive testing.
I've started to run some of my test codes to compare
certain functions in a clang-compiled libm, gcc-compiled
libm, and reference solutions generated from math/mpfr.
For a locally patched j0f, I found that clang gave
much worse accuracy.  If I revert the local patch,
clang and gcc are to give the same results.  Unfortnately,
an unpatched j0f gives 500000 ULP errors.

-- 
Steve