[LLVM-C][Ocaml] Add MergeFunctions and DCE pass

MergeFunctions and DCE pass are missing from OCaml/C-api. This patch
adds them.

Differential Revision: https://reviews.llvm.org/D65071

Reviewers: whitequark, hiraditya, deadalnix

Reviewed By: whitequark

Subscribers: llvm-commits

Tags: #llvm

Authored by: kren1

llvm-svn: 373170
diff --git a/llvm/lib/Transforms/Scalar/Scalar.cpp b/llvm/lib/Transforms/Scalar/Scalar.cpp
index 869cf00..688b8b9 100644
--- a/llvm/lib/Transforms/Scalar/Scalar.cpp
+++ b/llvm/lib/Transforms/Scalar/Scalar.cpp
@@ -123,6 +123,10 @@
   unwrap(PM)->add(createAggressiveDCEPass());
 }
 
+void LLVMAddDCEPass(LLVMPassManagerRef PM) {
+  unwrap(PM)->add(createDeadCodeEliminationPass());
+}
+
 void LLVMAddBitTrackingDCEPass(LLVMPassManagerRef PM) {
   unwrap(PM)->add(createBitTrackingDCEPass());
 }