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Re: [RFC] Fix PR28684
- From: Revital1 Eres <ERES at il dot ibm dot com>
- To: Richard Guenther <rguenther at suse dot de>
- Cc: Ayal Zaks <ZAKS at il dot ibm dot com>, Dorit Nuzman <DORIT at il dot ibm dot com>, gcc-patches at gcc dot gnu dot org, roger at eyesopen dot com, Clint Whaley <whaley at cs dot utsa dot edu>
- Date: Thu, 16 Nov 2006 16:30:33 +0200
- Subject: Re: [RFC] Fix PR28684
> I believe we may also inhibit or create underflow or overflow with
> re-ordering for example
> (X + C1) - C2 to X + (C1 - C2)
> for X near FLT_MAX and C1 sufficiently large.
> Even transforming
> X + Y - Y to X
> may fail to propagate a NaN Y to the result.
Is transforming X + Y - Y to X is allowed by our flag?
Isn't it like x * 0 -> 0?