rL305193-backport

rL305193-backport

commit 2b622a393ce80c6157d32a50bf67d6b830729469
Author: Than McIntosh <thanm@google.com>
Date:   Mon Jun 12 14:56:02 2017 +0000

    StackColoring: smarter check for slot overlap

    Summary:
    The old check for slot overlap treated 2 slots `S` and `T` as
    overlapping if there existed a CFG node in which both of the slots could
    possibly be active. That is overly conservative and caused stack blowups
    in Rust programs. Instead, check whether there is a single CFG node in
    which both of the slots are possibly active *together*.

    Fixes PR32488.

    Patch by Ariel Ben-Yehuda <ariel.byd@gmail.com>

    Reviewers: thanm, nagisa, llvm-commits, efriedma, rnk

    Reviewed By: thanm

    Subscribers: dotdash

    Differential Revision: https://reviews.llvm.org/D31583

    git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@305193 91177308-0d34-0410-b5e6-96231b3b80d8

Gbp-Pq: Name rL305193-backport.diff