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Re: optimization/9052: in C code, "if" statement fails to execute if optimized
- From: Steven Bosscher <s dot bosscher at student dot tudelft dot nl>
- To: Eric Botcazou <ebotcazou at libertysurf dot fr>
- Cc: Richard dot Earnshaw at arm dot com, gcc-gnats at gcc dot gnu dot org,gcc-bugs at gcc dot gnu dot org, nobody at gcc dot gnu dot org, phama at webjockey dot net
- Date: 12 Feb 2003 18:01:20 +0100
- Subject: Re: optimization/9052: in C code, "if" statement fails to execute if optimized
- References: <200302121624.h1CGO9G31917@pc960.cambridge.arm.com> <200302121754.54649.ebotcazou@libertysurf.fr>
Op wo 12-02-2003, om 17:55 schreef Eric Botcazou:
> > Adding -ffloat-store will probably also make the "misbehaviour" go away.
>
> It does.
>
> > GCC is almost certainly using the register result from the current
> > iteration to compare with the memory result from an earlier iteration.
> > Since the register result has excess precision the compare for equality
> > fails. That's not a bug, it's just the FP works on the X86.
> >
> > So in summary, almost certainly "not a bug".
>
> I fully concur. I think the PR can be closed.
>
Nice, one more PR gone (still too many to go :-/).
How about 8445, 9654? Those are "bugs" that disappear with
-ffloat-store, too. Like I said, I don't know enough about floating
point numbers...
Greetz
Steven