[PM] Port EarlyCSE to the new pass manager.

I've added RUN lines both to the basic test for EarlyCSE and the
target-specific test, as this serves as a nice test that the TTI layer
in the new pass manager is in fact working well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227725 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Transforms/Scalar/EarlyCSE.h

@@ -0,0 +1,45 @@
+//===- EarlyCSE.h - Simple and fast CSE pass --------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file provides the interface for a simple, fast CSE pass.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_SCALAR_EARLYCSE_H
+#define LLVM_TRANSFORMS_SCALAR_EARLYCSE_H
+
+#include "llvm/IR/Function.h"
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+/// \brief A simple and fast domtree-based CSE pass.
+///
+/// This pass does a simple depth-first walk over the dominator tree,
+/// eliminating trivially redundant instructions and using instsimplify to
+/// canonicalize things as it goes. It is intended to be fast and catch obvious
+/// cases so that instcombine and other passes are more effective. It is
+/// expected that a later pass of GVN will catch the interesting/hard cases.
+class EarlyCSEPass {
+public:
+  static StringRef name() { return "EarlyCSEPass"; }
+
+  /// \brief Run the pass over the function.
+  ///
+  /// This will lower all of th expect intrinsic calls in this function into
+  /// branch weight metadata. That metadata will subsequently feed the analysis
+  /// of the probabilities and frequencies of the CFG. After running this pass,
+  /// no more expect intrinsics remain, allowing the rest of the optimizer to
+  /// ignore them.
+  PreservedAnalyses run(Function &F, AnalysisManager<Function> *AM);
+};
+
+}
+
+#endif