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Re: New option to turn off stack reuse for temporaries

From: Jason Merrill <jason at redhat dot com>
To: Richard Guenther <richard dot guenther at gmail dot com>
Cc: Xinliang David Li <davidxl at google dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, Michael Matz <matz at suse dot de>
Date: Thu, 21 Jun 2012 10:50:41 -0700
Subject: Re: New option to turn off stack reuse for temporaries
References: <CAAkRFZK_27tveOTLioz-YwfF_4w4qtTJkRFjno7r8risRVQsnQ@mail.gmail.com> <4FE26AFC.3000703@redhat.com> <CAAkRFZL_WkRtxRD4_U=_KzfPGtnmf=QxJSN_E=KfROKwTALjHQ@mail.gmail.com> <CAFiYyc2_genu4SOJ963YqforcuopxXDWYXUeC6=66V-2pYEPXw@mail.gmail.com>

On 06/21/2012 02:21 AM, Richard Guenther wrote:

The flag is not restricted to the C++ compiler and applies to all automatic
variables.

This only affects the clobbers for C++ temporary objects, not clobbers for automatic variables going out of scope.

Also with this patch you remove code motion barriers which might cause
other issues.

How so?

A more "proper" place to fix this is when we actually do the stack reuse,
in cfgexpand.

How would that distinguish between the clobbers for temporaries vs. automatics?

Jason

References:
- New option to turn off stack reuse for temporaries
  - From: Xinliang David Li
- Re: New option to turn off stack reuse for temporaries
  - From: Jason Merrill
- Re: New option to turn off stack reuse for temporaries
  - From: Xinliang David Li
- Re: New option to turn off stack reuse for temporaries
  - From: Richard Guenther

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