NewGVN: Don't try to kill off the stored value of stores when processing the congruence class of the store. Because we use the stored value of a store as the def, it isn't dead just because it appears as a def when it comes from a store.
NewGVN: Don't try to kill off the stored value of stores when
processing the congruence class of the store.
Because we use the stored value of a store as the def, it isn't dead
just because it appears as a def when it comes from a store.

Note: I have not hit any cases with the memory code as it is where
this breaks anything, just because of what memory congruences we
actually allow.  In a followup that improves memory congruence,
this bug actually breaks real stuff (but the verifier catches it).

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@299300 91177308-0d34-0410-b5e6-96231b3b80d8

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