Simplify strlen to a subtraction for certain cases.

Patch by Li Huang (li1.huang@intel.com)

Differential Revision: http://reviews.llvm.org/D18230


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266200 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed