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Re: Patch to rework IEEE floating point checks
- From: "Joseph S. Myers" <jsm28 at cam dot ac dot uk>
- To: Richard Sandiford <rsandifo at redhat dot com>
- Cc: <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 28 Feb 2002 21:50:12 +0000 (GMT)
- Subject: Re: Patch to rework IEEE floating point checks
On 28 Feb 2002, Richard Sandiford wrote:
> 3) Document what exactly makes each transformation right or wrong,
> which should make things easier to maintain. At the moment, most
> checks just say "not valid for IEEE" with no explanation why.
> And to show that there has been some confusion here, if x and y
> are IEEE floats, the tree level optimises "x + -y" into "x - y",
> but the RTL level doesn't.
>
> 4) Make it possible to add options like -fignore-signed-zeros,
> or whatever, as suboptions of -funsafe-math-optimizations.
> (More options might not be universally popular, though. ;-)
Another thing that would be desirable: allow tree and RTL expressions to
carry with them flags detailing which transformations are allowed. (This
is needed for the C99 standard pragmas, and I think it is useful for Java
as well.)
--
Joseph S. Myers
jsm28@cam.ac.uk