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Subject: Re: svn commit: r265367 - head/lib/libc/regex
From: David Chisnall <theraven@FreeBSD.org>
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Date: Mon, 5 May 2014 22:21:59 +0100
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To: Pedro Giffuni <pfg@FreeBSD.org>
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On 5 May 2014, at 20:49, Pedro Giffuni <pfg@FreeBSD.org> wrote:

> Yes, but I reverted it because there are other ways to check for =
overflows without the performance hit.

Do we have a good reusable routine for doing this somewhere?  Clang and =
gcc both have some idiom recognisers that try to spot when people are =
attempting to do this.  Clang also has a builtin, which would be good to =
use when available.  Overflow checking is very cheap on modern CPUs =
(add, branch on carry), so it would be nice if we could start looking =
for this malloc() and realloc() pattern and replacing the multiply with =
something that checks for the error.

David