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Re: [PATCH][middle-end] Make qsort in tree-ssa-sccvn.c stable.

From: Rafael Espindola <espindola at google dot com>
To: Michael Matz <matz at suse dot de>
Cc: Doug Kwan (éæå) <dougkwan at google dot com>, gcc-patches <gcc-patches at gcc dot gnu dot org>
Date: Tue, 12 May 2009 14:02:50 +0100
Subject: Re: [PATCH][middle-end] Make qsort in tree-ssa-sccvn.c stable.
References: <498552560905111859p6b0aaa21sb98953e57d950dfd@mail.gmail.com> <38a0d8450905120225w2a3e74a0y62b062e422254e3c@mail.gmail.com> <Pine.LNX.4.64.0905121438400.29566@wotan.suse.de>

> Unstability is only given when the comparison returns 0 for any other
> cases besides pointer equality. ÂIt could have been recoded by an a priori
> check for pa==pb, in which case it could be replaced by an
> gcc_unreachable, which indeed might be more clear.

True. Doing

gcc_assert (pa == pb);
return 0;

in the last else should be fine too.

>
> Ciao,
> Michael.

Cheers,
-- 
Rafael Avila de Espindola

Google | Gordon House | Barrow Street | Dublin 4 | Ireland
Registered in Dublin, Ireland | Registration Number: 368047

References:
- [PATCH][middle-end] Make qsort in tree-ssa-sccvn.c stable.
  - From: =?big5?b?RG91ZyBLd2FuICjD9q62vHcp?=
- Re: [PATCH][middle-end] Make qsort in tree-ssa-sccvn.c stable.
  - From: Rafael Espindola
- Re: [PATCH][middle-end] Make qsort in tree-ssa-sccvn.c stable.
  - From: Michael Matz

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