The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/2ab09351d60ab39ce4083d888880e9c981d81e06

commit 2ab09351d60ab39ce4083d888880e9c981d81e06
Author: Yunlian Jiang <yunlian@chromium.org>
Date: Wed Feb 21 12:27:04 2018

llvm: Cherrypick a fix to ValueMapper

This cherrypickes 61c5605f601c14b58d9697c7b625f2082daed65d, which fixes
a bug exposed during ThinLTO compilation.

Original commit message:
commit 61c5605f601c14b58d9697c7b625f2082daed65d
Author: Teresa Johnson <tejohnson@google.com>
Date:   Tue Jan 30 20:16:32 2018 +0000

    Teach ValueMapper to use ODR uniqued types when available

    Summary:
    This is exposed during ThinLTO compilation, when we import an alias by
    creating a clone of the aliasee. Without this fix the debug type is
    unnecessarily cloned and we get a duplicate, undoing the uniquing.

    Fixes PR36089.

BUG= chromium:813109 
TEST=cbuildbot chromiumos-sdk chell-llvm-toolchain-tryjob
     kevin-llvm-toolchain-tryjob --hwtest
     USE="thinlto afdo_use" emerge-samus chromeos-chrome

Change-Id: I51c9f14dcbe09fd5e2317f5db09608ecc67ee610
Reviewed-on: https://chromium-review.googlesource.com/926707
Commit-Ready: Yunlian Jiang <yunlian@chromium.org>
Tested-by: Yunlian Jiang <yunlian@chromium.org>
Reviewed-by: Manoj Gupta <manojgupta@chromium.org>

[rename] https://crrev.com/2ab09351d60ab39ce4083d888880e9c981d81e06/sys-libs/compiler-rt/compiler-rt-6.0_pre321490-r2.ebuild
[rename] https://crrev.com/2ab09351d60ab39ce4083d888880e9c981d81e06/sys-devel/llvm/llvm-6.0_pre321490_p20180131-r3.ebuild
[add] https://crrev.com/2ab09351d60ab39ce4083d888880e9c981d81e06/sys-devel/llvm/files/cherry/61c5605f601c14b58d9697c7b625f2082daed65d.patch