SV: [PATCH] D24861: [Sema] extend Wshift-op-parentheses so it warns for multiplicative operators

[Daniel Marjamäki via cfe-commits]

Hello!

Moving it to a subgroup such as -Wparentheses is fine for me. I will look at that when I have time. Do you think this warning has an acceptable output then?

Best regards,
Daniel Marjamäki

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Daniel Marjamäki Senior Engineer
Evidente ES East AB  Warfvinges väg 34  SE-112 51 Stockholm  Sweden

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________________________________________
Från: Richard Trieu [rtrieu at google.com]
Skickat: den 1 oktober 2016 00:41
Till: reviews+D24861+public+1ab88c6ac93f51fd at reviews.llvm.org
Kopia: Daniel Marjamäki; David Blaikie; joerg at netbsd.org; bruno.cardoso at gmail.com; cfe-commits
Ämne: Re: [PATCH] D24861: [Sema] extend Wshift-op-parentheses so it warns for multiplicative operators

Currently, this warning is on by default.  As you said, the results you found look intentional in many cases, so there is a high false positive rate.  For on by default warnings, we expect a high true positive rate and intend for users to not disable the warning.  From my analysis on a separate codebase, I found less than 10% true positive rate out of 200 warnings.  One option might be to move this warning to a subgroup, which would leave it discoverable from either -Wall or -Wparentheses, but not have it on by default.

On Wed, Sep 28, 2016 at 4:09 AM, Daniel Marjamäki <daniel.marjamaki at evidente.se<mailto:daniel.marjamaki at evidente.se>> wrote:
danielmarjamaki added a comment.

I updated the patch so it does not warn about 'A * B << C'. It's a simple fix. I have not made careful measurements but I guess that the performance penalty is acceptable.


https://reviews.llvm.org/D24861