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Re: PATCH: [4.3 Regression] __builtin_strcpy doesn't work with -fstack-protector

From: Paolo Bonzini <bonzini at gnu dot org>
To: Richard Guenther <richard dot guenther at gmail dot com>
Cc: "H.J. Lu" <hjl dot tools at gmail dot com>, gcc-patches at gcc dot gnu dot org, jakub at redhat dot com
Date: Tue, 20 Jan 2009 11:55:13 +0100
Subject: Re: PATCH: [4.3 Regression] __builtin_strcpy doesn't work with -fstack-protector
References: <20090119202922.GA31233@lucon.org> <84fc9c000901200049k44d7a22amc6cc11d0ad338247@mail.gmail.com>

Richard Guenther wrote:
> On Mon, Jan 19, 2009 at 9:29 PM, H.J. Lu <hongjiu.lu@intel.com> wrote:
>> Hi,
>>
>> Gcc 4.3 may not set memory size correctly on x86 when inlining string
>> functions.  As the result, scheduler may move insns around and
>> generate wrong code.  This backport works for me.  OK for 4.3?
> 
> Please make sure this does not cause PR38868 to regress.

I don't think so; the cause of PR38868 is that better canonicalization
of trees causes more MEM_EXPRs to appear, which are wrong due to an
RTL-level bug similar to the one HJ is fixing here.

Even if so, we have a patch for PR38868 and you may try backport it as well.

Paolo

References:
- PATCH: [4.3 Regression] __builtin_strcpy doesn't work with -fstack-protector
  - From: H.J. Lu
- Re: PATCH: [4.3 Regression] __builtin_strcpy doesn't work with -fstack-protector
  - From: Richard Guenther

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