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From: Mark Mitchell <mark@codesourcery.com>
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To: "H.J. Lu" <hjl.tools@gmail.com>
CC: Richard Guenther <richard.guenther@gmail.com>,  Jakub Jelinek <jakub@redhat.com>, GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: PATCH: Turn on -fomit-frame-pointer by default for 32bit 	Linux/x86
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H.J. Lu wrote:

>> If I could, I'd go back in time and eliminate ABIs that use frame
>> pointers.  The use of unwind tables is, IMHO, a clearly superior

> The stack layout at function entry is the same as x86-64 psABI. I understand
> the old backtrace codes depend on the frame pointer, but it isn't mandated
> by the psABI.

Sure, but the psABI document is less relevant than existing practice.  I
don't think it's relevant to this discussion.  Let's not talk about it.

The important issue is that there is a lot of code out there that
probably assumes a frame pointer, and it will stop working.  We have to
weigh that against the fact that the code that doesn't stop working will
run faster.

Thanks,

-- 
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713