[nvvm] Mark ldu and ldg intrinsics as IntrArgMemOnly.
[nvvm] Mark ldu and ldg intrinsics as IntrArgMemOnly.

Summary:
Previously these intrinsics were marked as can-read any memory address.
Now they're marked as reading only the pointer they're passed.

Reviewers: rnk

Subscribers: jholewinski, llvm-commits, tra

Differential Revision: http://reviews.llvm.org/D20080

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@268996 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm