Documentation: http://llvm.org/doxygen/structllvm_1_1EarlyCSEPass.html

Bug: b/135609394
Change-Id: Ie7c6a99be46832797c3871b00fee33dea979f207
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/33951
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Tested-by: Ben Clayton <bclayton@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>