libstdc++/8230: Buggy allocator behaviour

[Richard Henderson]

The following reply was made to PR libstdc++/8230; it has been noted by GNATS.

From: Richard Henderson <rth@redhat.com>
To: Gabriel Dos Reis <gdr@integrable-solutions.net>
Cc: Matt Austern <austern@apple.com>, Benjamin Kosnik <bkoz@redhat.com>,
   bkoz@gcc.gnu.org, gcc-bugs@gcc.gnu.org, jkanze@caicheuvreux.com,
   gcc-gnats@gcc.gnu.org, libstdc++@gcc.gnu.org
Subject: Re: libstdc++/8230: Buggy allocator behaviour
Date: Fri, 15 Nov 2002 14:41:38 -0800

 On Thu, Nov 14, 2002 at 11:27:17PM +0100, Gabriel Dos Reis wrote:
 > Maybe RTH could provide us with some datapoint here?
 
 "It depends".
 
 > | Second, if the answer to question 1 is "a lot": is there some sensible
 > | way to use this in the compiler itself?  I suppose it'd have to involve
 > | some ghastly macro hackery because of the bootstrap problem, but
 > | it we're talking big performance wins, it might be worth it.
 > 
 > If the answer to the first question is "a lot", then I agree with you
 > that it makes perfect sense to use it in the compiler itself.  I
 > could imagine something along the lines
 > 
 > #if !defined(__GNUC__) || __GNUC__ < 3  /* correct the version number */
 > #  define __builtin_expect(EXP, PROB) EXP
 > #endif
 > 
 > in system.h or wherever appropriate.
 
 I don't think it's worth it, except _possibly_ in the 
 ENABLE_CHECKING macros.
 
 
 r~