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List:       sqlite-users
Subject:    Re: [sqlite] Q about integer overflow in sqlite3MulInt64().
From:       Richard Hipp <drh () sqlite ! org>
Date:       2016-09-21 1:05:49
Message-ID: CALwJ=MwVBJUYvdE36JT2JGO2TMyPq3fa0pw0POSKX5wwBavM9A () mail ! gmail ! com
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On 9/20/16, Scott Hess <shess@google.com> wrote:
> I also see that some systems
> include __builtin_mul_overflow() intrinsics, which can use the CPU's
> overflow flag, if available, which seems plausible.
>

I too have seen this, and look forward to the wide-spread availability
of these routines.  The functions are not available on my 4.8.4 GCC,
nor on MSVC 2012 (afaik).

Other intrinsic functions are used in SQLite.  For example:

     https://www.sqlite.org/src/artifact/3e2da61018?ln=1135-1157

Intrinsic functions can make a big difference in performance.
-- 
D. Richard Hipp
drh@sqlite.org
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