Last good:
https://build.chromium.org/p/chromium.fyi/builders/ClangToTLinux/builds/8907
Clang: 311850

First bad:
https://build.chromium.org/p/chromium.fyi/builders/ClangToTLinux/builds/8908
Clang: 311866

Prime suspect:

------------------------------------------------------------------------
r311857 | mehdi_amini | 2017-08-27 13:24:09 -0700 (Sun, 27 Aug 2017) | 6 lines

Emit static constexpr member as available_externally definition

By exposing the constant initializer, the optimizer can fold many
of these constructs.

Differential Revision: https://reviews.llvm.org/D34992
------------------------------------------------------------------------

 Issue 759746  has been merged into this issue.

Attaching repro source and invocation.

Deleted: hid_service_linux-0c7e64.sh 8.7 KB

hid_service_linux-0c7e64.sh 8.7 KB View Download

Deleted: hid_service_linux-0c7e64.cpp 5.2 MB

hid_service_linux-0c7e64.cpp 5.2 MB View Download

Upstream bug: https://bugs.llvm.org/show_bug.cgi?id=34348

Reverted in r311898