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*From*: Kenneth Zadeck <zadeck at naturalbridge dot com>*To*: Robert Dewar <dewar at adacore dot com>*Cc*: Richard Biener <richard dot guenther at gmail dot com>, Mike Stump <mikestump at comcast dot net>, gcc-patches <gcc-patches at gcc dot gnu dot org>, Lawrence Crowl <crowl at google dot com>, rdsandiford at googlemail dot com, Ian Lance Taylor <iant at google dot com>*Date*: Mon, 08 Apr 2013 09:24:46 -0400*Subject*: Re: Comments on the suggestion to use infinite precision math for wide int.*References*: <506C72C7 dot 7090207 at naturalbridge dot com> <87pq3y3kyk dot fsf at sandifor-thinkpad dot stglab dot manchester dot uk dot ibm dot com> <CAFiYyc3NjOxpQ-Y9GDrQOET+dc3LXWuiuM=DxqmyASE8urRoWw at mail dot gmail dot com> <50912D85 dot 1070002 at naturalbridge dot com> <CAFiYyc2Q2UQPmkhExi2c8f-BSGLv+Rq1rOy4NdPQmTqSRE1A0A at mail dot gmail dot com> <5091331C dot 3030504 at naturalbridge dot com> <CAFiYyc1L6zuehE75dEfd_fB1-81F1fDHpL3kS=tbk6qAK3Texg at mail dot gmail dot com> <512D686B dot 90000 at naturalbridge dot com> <CAFiYyc3fXewAW2dU6-RHLiTQ-ZiLgdWmfwdFF6k1VqxPsrvZbQ at mail dot gmail dot com> <515B16EB dot 5020303 at naturalbridge dot com> <CAFiYyc2qWwDcqzCMpMSiQ72w5ry=a3ZpxkFkiK7OvvBA0h4eGw at mail dot gmail dot com> <515C1AFB dot 3080105 at naturalbridge dot com> <CAFiYyc12qGj92j+5yCUEpghOZXqjjAgOzS_H6QJpKvd-dyfU0A at mail dot gmail dot com> <515C55D7 dot 7020003 at naturalbridge dot com> <CAFiYyc0sp1wbq1J+FXoJWcb9UcsOWiwjJ_KaQkbbgCnddxhVzA at mail dot gmail dot com> <5161AA07 dot 7090706 at naturalbridge dot com> <CAFiYyc1QArda2jm56=eT_ugqX39m4tW=gf7FCowuruq-xOdQGg at mail dot gmail dot com> <5162BB64 dot 3070007 at naturalbridge dot com> <5162C019 dot 5030405 at adacore dot com>

On 04/08/2013 09:03 AM, Robert Dewar wrote:

It may be interesting to look at what we have done in Ada with regard to overflow in intermediate expressions. Briefly we allow specification of three modes all intermediate arithmetic is done in the base type, with overflow signalled if an intermediate value is outside this range. all intermediate arithmetic is done in the widest integer type, with overflow signalled if an intermediate value is outside this range. all intermediate arithmetic uses an infinite precision arithmetic package built for this purpose. In the second and third cases we do range analysis that allows smaller intermediate precision if we know it's safe. We also allow separate specification of the mode inside and outside assertions (e.g. preconditions and postconditions) since in the latter you often want to regard integers as mathematical, not subject to intermediate overflow.

Otherwise, how could ada have ever worked with gcc? kenny

**Follow-Ups**:**Re: Comments on the suggestion to use infinite precision math for wide int.***From:*Robert Dewar

**References**:**Re: patch to fix constant math - 4th patch - the wide-int class - patch ping for the next stage 1***From:*Richard Biener

**Re: patch to fix constant math - 4th patch - the wide-int class - patch ping for the next stage 1***From:*Kenneth Zadeck

**Re: patch to fix constant math - 4th patch - the wide-int class - patch ping for the next stage 1***From:*Richard Biener

**Re: patch to fix constant math - 4th patch - the wide-int class - patch ping for the next stage 1***From:*Kenneth Zadeck

**Re: patch to fix constant math - 4th patch - the wide-int class - patch ping for the next stage 1***From:*Richard Biener

**Re: patch to fix constant math - 4th patch - the wide-int class - patch ping for the next stage 1***From:*Kenneth Zadeck

**Re: patch to fix constant math - 4th patch - the wide-int class - patch ping for the next stage 1***From:*Richard Biener

**Comments on the suggestion to use infinite precision math for wide int.***From:*Kenneth Zadeck

**Re: Comments on the suggestion to use infinite precision math for wide int.***From:*Richard Biener

**Re: Comments on the suggestion to use infinite precision math for wide int.***From:*Kenneth Zadeck

**Re: Comments on the suggestion to use infinite precision math for wide int.***From:*Robert Dewar

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