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Re: Is it OK that gcc optimizes away overflow check?

From: Andrew Haley <aph at redhat dot com>
To: gcc-help at gcc dot gnu dot org
Date: Tue, 26 Jul 2011 17:37:27 +0100
Subject: Re: Is it OK that gcc optimizes away overflow check?
References: <4E2B2B72.9050504@agner.org> <mcr4o2arj57.fsf@coign.corp.google.com> <4E2E8B12.1090204@agner.org> <4E2E9873.7060902@redhat.com>

On 07/26/2011 11:35 AM, Andrew Haley wrote:

> Consider
> 
>   for (i = 0; i < limit; i++)
>     f(i * 2);
> 
> which can be rewritten to
> 
>   tmp = limit * 2;
>   for (i = 0; i < tmp; i++)
>     f(i);

duh.

  int tmp = limit * 2;
  for (i = 0; i < tmp; i += 2)
    f(i);

Andrew.

Follow-Ups:
- Re: Is it OK that gcc optimizes away overflow check?
  - From: Agner Fog

References:
- Is it OK that gcc optimizes away overflow check?
  - From: Agner Fog
- Re: Is it OK that gcc optimizes away overflow check?
  - From: Ian Lance Taylor
- Re: Is it OK that gcc optimizes away overflow check?
  - From: Agner Fog
- Re: Is it OK that gcc optimizes away overflow check?
  - From: Andrew Haley

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