[Python-Dev] sre vs gcc (was: New re failures on Windows)

Andrew MacIntyre andymac@bullseye.apana.org.au
Tue, 22 Apr 2003 19:27:01 +1100 (edt)

[redirected to people apparently working on SRE]
On Mon, 21 Apr 2003, Tim Peters wrote:

> Narrowing it down to the specific C code that's at fault is still the best
> hope.  There are two reasons for that:
> 1. It's very easy to write ill-defined code in C, and for all we know
>    now some part of _sre is depending on undefined, or implementation
>    defined (but apparently likely), behavior.
> 2. If that's not the problem, optimization bugs are usually easy to
>    sidestep via minor code changes.  You have to know which code is
>    getting screwed first, though.

Seeing that Gustavo had checked in some changes to _sre.c on Sunday, I CVS
up'ed and now find that a gcc 2.95.4 build survives test_sre with -O3.
A gcc 3.2.2 build still gets a bus error with either -O3 or -O2.

The actual test case from test_sre that fails is:
# non-simple '*?' still recurses and hits the recursion limit
test(r"""sre.search('(a|b)*?c', 10000*'ab'+'cd').end(0)""", None, RuntimeError)

For the moment, the FreeBSD 5.x (ie gcc 3.2.x) element of my configure.in
patch (SF #725024) is still valid.

Andrew I MacIntyre                     "These thoughts are mine alone..."
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