Merging r276479:

Merging r276479:
------------------------------------------------------------------------
r276479 | asbirlea | 2016-07-22 15:02:19 -0700 (Fri, 22 Jul 2016) | 11 lines

Add flag to PassManagerBuilder to disable GVN Hoist Pass.

Summary:
Adding a flag to diable GVN Hoisting by default.
Note: The GVN Hoist Pass causes some Halide tests to hang. Halide will disable the pass while investigating.

Reviewers: llvm-commits, chandlerc, spop, dberlin

Subscribers: mehdi_amini

Differential Revision: https://reviews.llvm.org/D22639
------------------------------------------------------------------------

git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_39@276647 91177308-0d34-0410-b5e6-96231b3b80d8