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Re: [PATCH] i386: Don't use frame pointer without stack access

From: Michael Matz <matz at suse dot de>
To: Uros Bizjak <ubizjak at gmail dot com>
Cc: "H.J. Lu" <hjl dot tools at gmail dot com>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
Date: Mon, 7 Aug 2017 15:15:04 +0200 (CEST)
Subject: Re: [PATCH] i386: Don't use frame pointer without stack access
Authentication-results: sourceware.org; auth=none
References: <20170806194037.GA25845@gmail.com> <CAFULd4Z-OicMFZTRS-3PiOQRSFxfNrkUP+O5pb7R-Uw-tSzfcw@mail.gmail.com>

Hi,

On Mon, 7 Aug 2017, Uros Bizjak wrote:

> On Sun, Aug 6, 2017 at 9:40 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> > When there is no stack access, there is no need to use frame pointer
> > even if -fno-omit-frame-pointer is used.
> >
> > Tested on i686 and x86-64.  OK for trunk?
> 
> LGTM.

This will break unwinders relying on frame pointers to exist on all 
functions, for which projects conciously forced a frame pointer with this 
option.  I don't think we can simply override user specified explicit 
wishes in this way, presumably they had a reason to use it.

Ciao,
Michael.

Follow-Ups:
- Re: [PATCH] i386: Don't use frame pointer without stack access
  - From: Uros Bizjak

References:
- [PATCH] i386: Don't use frame pointer without stack access
  - From: H.J. Lu
- Re: [PATCH] i386: Don't use frame pointer without stack access
  - From: Uros Bizjak

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