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Re: [RFC] Fix PR28684
- From: Clint Whaley <whaley at cs dot utsa dot edu>
- To: whaley at cs dot utsa dot edu, ERES at il dot ibm dot com
- Cc: ZAKS at il dot ibm dot com, whaley at cs dot utsa dot edu, roger at eyesopen dot com, rguenther at suse dot de, gcc-patches at gcc dot gnu dot org, DORIT at il dot ibm dot com
- Date: Thu, 16 Nov 2006 10:42:39 -0600
- Subject: Re: [RFC] Fix PR28684
- References: <OFC9698BC6.7246A440-ONC2257228.00562F3C-C2257228.00590C7A@il.ibm.com>
>vectorization does not need strength reduction so far.
>I did not see such transformation in the list of transformations
>which I though might fit the flag.
>The fact that it is not controlled by the flag
>was implicitly mentioned in the definition -
>An example of a transformation which is not allowed by this flag is
>transforming x * 0 to 0 as the result is not IEEE compliant when x
>Should I add a comment about it in the definition?
I don't think we need to comment things we *don't* do :) However, I think
strength reduction crept into the discussion based on this line from the
most recent discussion:
>NOTE: may reorder or strength reduce floating-point comparisons as
>well, and so may not be used when ordered comparisons are required.
I think this is a hold-over from an earlier discussion, where strength
reduction was in the set of flags. Based on what you say above, maybe
this should be reworded:
>NOTE: may reorder floating-point comparisons as well, and so may not be
>used when ordered comparisons are required.