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From: rridge@csclub.uwaterloo.ca (Ross Ridge)
To: gcc@gcc.gnu.org
Subject: Re: [PATCH][GIT PULL][v2.6.32] tracing/x86: Add check to detect GCC messing with mcount prologue
Date: Tue, 24 Nov 2009 17:05:00 -0000	[thread overview]
Message-ID: <20091124170457.2E96F1D8D1@caffeine.csclub.uwaterloo.ca> (raw)

Andrew Haley writes:
>Alright.  So, it is possible in theory for gcc to generate code that
>only uses -maccumulate-outgoing-args when it needs to realign SP.
>And, therefore, we could have a nice option for the kernel: one with
>(mostly) good code density and never generates the bizarre code
>sequence in the prologue.

The best option would be for the Linux people to fix the underlying
problem in their kernel sources.  If the code no longer requested
that certain automatic variables be aligned, then not only would this
bizarre code sequence not be emitted, the unnecessary stack alignment
would disapear as well.  The kernel would then be free to choose to use
whatever code generation options it felt was appropriate.

				Ross Ridge

             reply	other threads:[~2009-11-24 17:05 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-11-24 17:05 Ross Ridge [this message]
2009-11-24 17:11 ` Andrew Haley
     [not found] <alpine.LFD.2.00.0911181933540.24119@localhost.localdomain>
     [not found] ` <tip-887a29f59b93cf54e21814869a4ab6e80b6fa623@git.kernel.org>
     [not found]   ` <20091119072040.GA23579@elte.hu>
     [not found]     ` <alpine.LFD.2.00.0911191053390.24119@localhost.localdomain>
     [not found]       ` <alpine.LFD.2.00.0911191423190.24119@localhost.localdomain>
2009-11-20  5:24         ` Steven Rostedt
2009-11-20  5:33           ` Steven Rostedt
2009-11-20 17:02           ` Steven Rostedt
2009-11-20 17:15             ` H. Peter Anvin
2009-11-20 19:36             ` Andrew Haley
2009-11-20 19:48               ` Steven Rostedt
2009-11-20 19:50                 ` H. Peter Anvin
2009-11-22  9:39               ` H.J. Lu
2009-11-22 17:21                 ` Andrew Haley
2009-11-22 23:31                   ` H.J. Lu
2009-11-24 14:43                     ` Andrew Haley
2009-11-24 14:56                       ` Thomas Gleixner
2009-11-24 15:06                         ` Jakub Jelinek
2009-11-24 15:32                           ` Andrew Haley
2009-11-24 15:36                             ` Jakub Jelinek
2009-11-24 15:48                               ` Andrew Haley
2009-11-24 16:39                                 ` H. Peter Anvin
2009-11-24 17:12                                   ` Andrew Haley
2009-11-24 17:30                                     ` Steven Rostedt
2009-11-25 20:05                                       ` H. Peter Anvin
2009-11-24 19:56                                     ` H. Peter Anvin
2009-11-25 15:29                           ` Thomas Gleixner
2009-11-25 15:45                             ` Ingo Molnar
2009-11-25 15:53                               ` Thomas Gleixner
2009-11-25 16:26                                 ` Ingo Molnar
2009-11-25 16:45                               ` Jakub Jelinek
2009-11-25 20:13                                 ` H. Peter Anvin
2009-11-25 21:01                                   ` Andrew Haley
2009-11-22  9:06             ` Ingo Molnar

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