[PM] Port LowerExpectIntrinsic to the new pass manager.

This just lifts the logic into a static helper function, sinks the
legacy pass to be a trivial wrapper of that helper fuction, and adds
a trivial wrapper for the new PM as well. Not much to see here.

I switched a test case to run in both modes, but we have to strip the
dead prototypes separately as that pass isn't in the new pass manager
(yet).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226999 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Transforms/Scalar/LowerExpectIntrinsic.h

@@ -0,0 +1,40 @@
+//===- LowerExpectIntrinsic.h - LowerExpectIntrinsic pass -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+///
+/// The header file for the LowerExpectIntrinsic pass as used by the new pass
+/// manager.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_SCALAR_LOWEREXPECTINTRINSIC_H
+#define LLVM_TRANSFORMS_SCALAR_LOWEREXPECTINTRINSIC_H
+
+#include "llvm/IR/Function.h"
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+class LowerExpectIntrinsicPass {
+public:
+  static StringRef name() { return "LowerExpectIntrinsicPass"; }
+
+  /// \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);
+};
+
+}
+
+#endif

lib/Transforms/Scalar/LowerExpectIntrinsic.cpp

@@ -11,7 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Scalar/LowerExpectIntrinsic.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/IR/BasicBlock.h"
@@ -25,6 +25,7 @@
 #include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Transforms/Scalar.h"
 
 using namespace llvm;
 
@@ -40,24 +41,6 @@ static cl::opt<uint32_t>
 UnlikelyBranchWeight("unlikely-branch-weight", cl::Hidden, cl::init(4),
                    cl::desc("Weight of the branch unlikely to be taken (default = 4)"));
 
-namespace {
-/// \brief Legacy pass for lowering expect intrinsics out of the IR.
-///
-/// When this pass is run over a function it uses expect intrinsics which feed
-/// branches and switches to provide branch weight metadata for those
-/// terminators. It then removes the expect intrinsics from the IR so the rest
-/// of the optimizer can ignore them.
-class LowerExpectIntrinsic : public FunctionPass {
-public:
-  static char ID;
-  LowerExpectIntrinsic() : FunctionPass(ID) {
-    initializeLowerExpectIntrinsicPass(*PassRegistry::getPassRegistry());
-  }
-
-  bool runOnFunction(Function &F) override;
-};
-}
-
 static bool handleSwitchExpect(SwitchInst &SI) {
   CallInst *CI = dyn_cast<CallInst>(SI.getCondition());
   if (!CI)
@@ -143,7 +126,7 @@ static bool handleBranchExpect(BranchInst &BI) {
   return true;
 }
 
-bool LowerExpectIntrinsic::runOnFunction(Function &F) {
+static bool lowerExpectIntrinsic(Function &F) {
   bool Changed = false;
 
   for (BasicBlock &BB : F) {
@@ -175,6 +158,31 @@ bool LowerExpectIntrinsic::runOnFunction(Function &F) {
   return Changed;
 }
 
+PreservedAnalyses LowerExpectIntrinsicPass::run(Function &F) {
+  if (lowerExpectIntrinsic(F))
+    return PreservedAnalyses::none();
+
+  return PreservedAnalyses::all();
+}
+
+namespace {
+/// \brief Legacy pass for lowering expect intrinsics out of the IR.
+///
+/// When this pass is run over a function it uses expect intrinsics which feed
+/// branches and switches to provide branch weight metadata for those
+/// terminators. It then removes the expect intrinsics from the IR so the rest
+/// of the optimizer can ignore them.
+class LowerExpectIntrinsic : public FunctionPass {
+public:
+  static char ID;
+  LowerExpectIntrinsic() : FunctionPass(ID) {
+    initializeLowerExpectIntrinsicPass(*PassRegistry::getPassRegistry());
+  }
+
+  bool runOnFunction(Function &F) override { return lowerExpectIntrinsic(F); }
+};
+}
+
 char LowerExpectIntrinsic::ID = 0;
 INITIALIZE_PASS(LowerExpectIntrinsic, "lower-expect",
                 "Lower 'expect' Intrinsics", false, false)

test/Transforms/LowerExpectIntrinsic/basic.ll

@@ -1,4 +1,5 @@
 ; RUN: opt -lower-expect -strip-dead-prototypes -S -o - < %s | FileCheck %s
+; RUN: opt -S -passes=lower-expect < %s | opt -strip-dead-prototypes -S | FileCheck %s
 
 ; CHECK-LABEL: @test1(
 define i32 @test1(i32 %x) nounwind uwtable ssp {

tools/opt/PassRegistry.def

@@ -63,6 +63,7 @@ FUNCTION_ANALYSIS("targetlibinfo", TargetLibraryAnalysis())
 FUNCTION_PASS("instcombine", InstCombinePass())
 FUNCTION_PASS("invalidate<all>", InvalidateAllAnalysesPass())
 FUNCTION_PASS("no-op-function", NoOpFunctionPass())
+FUNCTION_PASS("lower-expect", LowerExpectIntrinsicPass())
 FUNCTION_PASS("print", PrintFunctionPass(dbgs()))
 FUNCTION_PASS("print<assumptions>", AssumptionPrinterPass(dbgs()))
 FUNCTION_PASS("print<domtree>", DominatorTreePrinterPass(dbgs()))

tools/opt/Passes.cpp

@@ -26,6 +26,7 @@
 #include "llvm/IR/Verifier.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Transforms/InstCombine/InstCombine.h"
+#include "llvm/Transforms/Scalar/LowerExpectIntrinsic.h"
 
 using namespace llvm;