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Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."

From: Robert Dewar
Subject: Re: changing "configure" to default to "gcc -g -O2 -fwrapv ..."
Date: Sun, 31 Dec 2006 11:39:20 -0500
User-agent: Thunderbird (Windows/20061207)

Richard Kenner wrote:
Essentially, there are three choices: with -fwrapv, you must preseve wrapping
semantics and do NONE of those optimizations; with -fno-wrapv, you can do ALL
of them; in the default cause, a heuristic can be used that attempts to
balance optimization quality against breakage of old code.

Right, and such heuristics are certainly appropriate when you have
conflicting requirements, especially when both requirements

a) do all the optimizations possible
b) don't break existing code

are both ill defined

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