Re: [PATCH 2/2][v3] Drop excess size used for run time allocated stack variables.

[Dominik Vogt <vogt@linux.vnet.ibm.com>]

On Wed, May 25, 2016 at 02:32:41PM +0100, Dominik Vogt wrote:
> On Wed, May 25, 2016 at 02:30:54PM +0100, Dominik Vogt wrote:
> > On Tue, May 03, 2016 at 03:17:53PM +0100, Dominik Vogt wrote:
> > > Version two of the patch including a test case.
> > > 
> > > On Mon, May 02, 2016 at 09:10:25AM -0600, Jeff Law wrote:
> > > > On 04/29/2016 04:12 PM, Dominik Vogt wrote:
> > > > >The attached patch removes excess stack space allocation with
> > > > >alloca in some situations.  Plese check the commit message in the
> > > > >patch for details.
> > > 
> > > > However, I would strongly recommend some tests, even if they are
> > > > target specific.  You can always copy pr36728-1 into the s390x
> > > > directory and look at size of the generated stack.  Simliarly for
> > > > pr50938 for x86.
> > > 
> > > However, x86 uses the "else" branch in round_push, i.e. it uses
> > > "virtual_preferred_stack_boundary_rtx" to calculate the number of
> > > bytes to add for stack alignment.  That value is unknown at the
> > > time round_push is called, so the test case fails on such targets,
> > > and I've no idea how to fix this properly.
> > 
> > Third version of the patch with the suggested cleanup in the first
> > patch and the functional stuff in the second one.  The first patch
> > is based on Jeff's draft with the change suggested by Eric and
> > more cleanup added by me.
> 
> This is the updated funtional patch.  Re-tested with limited
> effort, i.e. tested and bootstrapped on s390x biarch (but did not
> look for performance regressions compared to version 2 of the
> patch).

(I won't be able to reply to any comments until 20th of June.)

Ciao

Dominik ^_^  ^_^

-- 

Dominik Vogt
IBM Germany