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Re: basic VRP min/max range overflow question

From: Paolo Bonzini <bonzini at gnu dot org>
To: gcc at gcc dot gnu dot org
Date: Fri, 17 Jun 2005 09:03:00 +0200
Subject: Re: basic VRP min/max range overflow question
References: <BED7C98B.A841%schlie@comcast.net>

Paul Schlie wrote:

Upon a potential integer overflow of either it's min or max range,
shouldn't the result be set to [min:type-min-value, max:type-max-value],
without the necessity of any further designations?

No.

[10, INT_MAX] + [ 1, 1 ] == [ 11, INT_MAX ] because of the famous signed int overflow definition in the C standard.

[10U, UINT_MAX] + [ 1U, 1U ] == ~[ 1U, 10U ]

Paolo

References:
- basic VRP min/max range overflow question
  - From: Paul Schlie

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