[LICM] Don't verify domtree/loopinfo unless EXPENSIVE_CHECKS is enabled.
[LICM] Don't verify domtree/loopinfo unless EXPENSIVE_CHECKS is enabled.

For large functions, verifying the whole function after each loop takes
non-linear time.

Differential Revision: https://reviews.llvm.org/D67571



git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@372924 91177308-0d34-0410-b5e6-96231b3b80d8

GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm