[Bug c/29186] optimzation breaks floating point exception flag reading

[joseph at codesourcery dot com]

------- Comment #8 from joseph at codesourcery dot com  2006-09-23 22:19 -------
Subject: Re:  optimzation breaks floating point exception flag
 reading

On Sat, 23 Sep 2006, kreckel at ginac dot de wrote:

> 
> 
> ------- Comment #7 from kreckel at ginac dot de  2006-09-23 22:11 -------
> (In reply to comment #6)
> > Use -frounding-math to enable FENV_ACCESS for the whole translation unit, 
> 
> Sorry, I fail to see what -frounding-math has to do with this. The example in
> comment #5 was about overflows and divisions by zero. Anyway, adding
> -frounding-math does not change anything in the case at hand.

Exceptions are meant to be covered by -ftrapping-math, which is on by 
default; with -frounding-math the whole of FENV_ACCESS should be enabled.

Although we don't implement the pragmas for control of these features in 
particular regions of code, we *do* have options that are meant to enable 
them for whole translation units.  So any failure of those options to 
disable problem optimizations is a bug which is *not* a duplicate of the 
lack of the pragmas.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29186