Merging r275866:

Merging r275866:
------------------------------------------------------------------------
r275866 | tnorthover | 2016-07-18 11:28:52 -0700 (Mon, 18 Jul 2016) | 6 lines

CodeGenPrep: use correct function to determine Global's alignment.

Elsewhere (particularly computeKnownBits) we assume that a global will be
aligned to the value returned by Value::getPointerAlignment. This is used to
boost the alignment on memcpy/memset, so any target-specific request can only
increase that value.
------------------------------------------------------------------------

git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_39@275918 91177308-0d34-0410-b5e6-96231b3b80d8