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Re: [PATCHv2] Add a warning for suspicious use of conditional expressions in boolean context

From: Joseph Myers <joseph at codesourcery dot com>
To: Bernd Edlinger <bernd dot edlinger at hotmail dot de>
Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Jason Merrill <jason at redhat dot com>
Date: Mon, 5 Sep 2016 16:46:22 +0000
Subject: Re: [PATCHv2] Add a warning for suspicious use of conditional expressions in boolean context
Authentication-results: sourceware.org; auth=none
References: <AM4PR0701MB21624AB3DECA1269E4BBB475E4E50@AM4PR0701MB2162.eurprd07.prod.outlook.com> <AM4PR0701MB2162C862449B51EF27F6AC52E4E70@AM4PR0701MB2162.eurprd07.prod.outlook.com> <alpine.DEB.2.20.1609051122070.30482@digraph.polyomino.org.uk> <AM4PR0701MB216214571A9BFAF1B1045812E4E60@AM4PR0701MB2162.eurprd07.prod.outlook.com>

On Mon, 5 Sep 2016, Bernd Edlinger wrote:

> But I think the reasoning is still correct, left shifting
> in a boolean context is suspicious, even if -fwrapv may make
> it defined.  Do you agree?

Well, you can argue that if you want to test whether low bits are all 
zero, you should just use binary & with a suitable mask, or else cast to 
unsigned for the left shift.

-- 
Joseph S. Myers
joseph@codesourcery.com

References:
- [PATCH] Add a warning for suspicious use of conditional expressions in boolean context
  - From: Bernd Edlinger
- [PATCHv2] Add a warning for suspicious use of conditional expressions in boolean context
  - From: Bernd Edlinger
- Re: [PATCHv2] Add a warning for suspicious use of conditional expressions in boolean context
  - From: Joseph Myers
- Re: [PATCHv2] Add a warning for suspicious use of conditional expressions in boolean context
  - From: Bernd Edlinger

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