Re: [Tinycc-devel] Fwd: Bug#698351: tcc: FE_INVALID flag not set on comparison with NAN (unordered)

[Vincent Lefevre]

Hi,

On 2013-01-17 15:57:50 +0100, Thomas Preud'homme wrote:
> I've just received this bug report in Debian. I don't know about
> this flag but if even gcc does the mistake, I think we can safely
> delay the fix for after the release, unless it's an easy fix. The
> bug report suggest there is just an instruction to change and that
> could be done easily I guess but as I said I don't know anything
> about this flag (first time I hear about it).

I've quickly looked at the source, but I'm not sure (I know almost
nothing about x86 / x86_64). One important point is that the
FE_INVALID flag must not be set for == and !=, and it seems that
the current code is shared by all these operations. I suppose that
a test op == TOK_EQ || op == TOK_NE could be sufficient to select
the right instruction.

My little program http://www.vinc17.net/software/tst-ieee754.c
could be useful to do some checking.

-- 
Vincent Lefèvre <address@hidden> - Web: <http://www.vinc17.net/>
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Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)