[llvm] r262505 - Revert "[X86] Elide references to _chkstk for dynamic allocas"

[Hans Wennborg via llvm-commits]

On Wed, Mar 2, 2016 at 11:21 AM, Reid Kleckner via llvm-commits
<llvm-commits at lists.llvm.org> wrote:
> Author: rnk
> Date: Wed Mar  2 13:20:59 2016
> New Revision: 262505
>
> URL: http://llvm.org/viewvc/llvm-project?rev=262505&view=rev
> Log:
> Revert "[X86] Elide references to _chkstk for dynamic allocas"
>
> This reverts commit r262370.
>
> It turns out there is code out there that does sequences of allocas
> greater than 4K: http://crbug.com/591404
>
> The goal of this change was to improve the code size of inalloca call
> sequences, but we got tangled up in the mess of dynamic allocas.
> Instead, we should come back later with a separate MI pass that uses
> dominance to optimize the full sequence. This should also be able to
> remove the often unneeded stacksave/stackrestore pairs around the call.

Do you want to file a bug blocking PR26299 so we don't lose track of this?