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Date: Wed, 06 Aug 2003 02:31:00 -0000
Subject: Re: On inlining in C++
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Cc: Andrew Pinski <pinskia@physics.uc.edu>, Geoff Keating <geoffk@geoffk.org>,
   Gabriel Dos Reis <gdr@integrable-solutions.net>, aph@redhat.com,
   coyote@coyotegulch.com, gcc@gcc.gnu.org
To: Joe Buck <jbuck@synopsys.com>
From: Andrew Pinski <pinskia@physics.uc.edu>
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On Tuesday, Aug 5, 2003, at 22:00 US/Eastern, Joe Buck wrote:

>
>>> There are tons of messages in this (or related thread) so it might be
>>> possible that I missed a message that disagreed with the
>>> interpretation of the documentation I quoted.  Can you give reference
>>> to such a message?
>
> On Tue, Aug 05, 2003 at 11:16:56AM -0700, Geoff Keating wrote:
>> I would point out that the documentation says "as fast as a macro",
>> but it should really say "as fast or faster than a macro".
>
> Ah, but even if we fix the inlining issues, we still aren't keeping the
> promise: inline functions are still slower in many cases if 
> struct/class
> objects with more than one member are passed by reference.
  (but that macro is not equivalent to that function).
>
> Compile the following code with "gcc -O2 -S il.C" using the trunk on 
> x86,
> and take a look.  The problem is that we prematurely commit the tmp 
> object
> to the stack, even though after inlining its address is not taken.

Yes this is a know defect in gcc which should be fixed soon on the 
tree-ssa branch,
it is not yet but it should be soon.

Thanks,
Andrew Pinski