Bring back "[PM] Port JumpThreading to the new PM" with a fix

This reverts commit r272603 and adds a fix.

Big thanks to Davide for pointing me at r216244 which gives some insight
into how to fix this VS2013 issue. VS2013 can't synthesize a move
constructor. So the fix here is to add one explicitly to the
JumpThreadingPass class.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272607 91177308-0d34-0410-b5e6-96231b3b80d8

Author: chisophugis

include/llvm/Transforms/Scalar/JumpThreading.h

@@ -0,0 +1,140 @@
+//===- JumpThreading.h - thread control through conditional BBs -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// See the comments on JumpThreadingPass.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_SCALAR_JUMPTHREADING_H
+#define LLVM_TRANSFORMS_SCALAR_JUMPTHREADING_H
+
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/Analysis/BlockFrequencyInfo.h"
+#include "llvm/Analysis/BranchProbabilityInfo.h"
+#include "llvm/Analysis/LazyValueInfo.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/ValueHandle.h"
+
+namespace llvm {
+
+/// A private "module" namespace for types and utilities used by
+/// JumpThreading.
+/// These are implementation details and should not be used by clients.
+namespace jumpthreading {
+// These are at global scope so static functions can use them too.
+typedef SmallVectorImpl<std::pair<Constant *, BasicBlock *>> PredValueInfo;
+typedef SmallVector<std::pair<Constant *, BasicBlock *>, 8> PredValueInfoTy;
+
+// This is used to keep track of what kind of constant we're currently hoping
+// to find.
+enum ConstantPreference { WantInteger, WantBlockAddress };
+}
+
+/// This pass performs 'jump threading', which looks at blocks that have
+/// multiple predecessors and multiple successors.  If one or more of the
+/// predecessors of the block can be proven to always jump to one of the
+/// successors, we forward the edge from the predecessor to the successor by
+/// duplicating the contents of this block.
+///
+/// An example of when this can occur is code like this:
+///
+///   if () { ...
+///     X = 4;
+///   }
+///   if (X < 3) {
+///
+/// In this case, the unconditional branch at the end of the first if can be
+/// revectored to the false side of the second if.
+///
+class JumpThreadingPass : public PassInfoMixin<JumpThreadingPass> {
+  TargetLibraryInfo *TLI;
+  LazyValueInfo *LVI;
+  std::unique_ptr<BlockFrequencyInfo> BFI;
+  std::unique_ptr<BranchProbabilityInfo> BPI;
+  bool HasProfileData;
+#ifdef NDEBUG
+  SmallPtrSet<const BasicBlock *, 16> LoopHeaders;
+#else
+  SmallSet<AssertingVH<const BasicBlock>, 16> LoopHeaders;
+#endif
+  DenseSet<std::pair<Value *, BasicBlock *>> RecursionSet;
+
+  unsigned BBDupThreshold;
+
+  // RAII helper for updating the recursion stack.
+  struct RecursionSetRemover {
+    DenseSet<std::pair<Value *, BasicBlock *>> &TheSet;
+    std::pair<Value *, BasicBlock *> ThePair;
+
+    RecursionSetRemover(DenseSet<std::pair<Value *, BasicBlock *>> &S,
+                        std::pair<Value *, BasicBlock *> P)
+        : TheSet(S), ThePair(P) {}
+
+    ~RecursionSetRemover() { TheSet.erase(ThePair); }
+  };
+
+public:
+  JumpThreadingPass(int T = -1);
+  // Hack for MSVC 2013 which seems like it can't synthesize this.
+  JumpThreadingPass(JumpThreadingPass &&Other)
+      : TLI(Other.TLI), LVI(Other.LVI), BFI(std::move(Other.BFI)),
+        BPI(std::move(Other.BPI)), HasProfileData(Other.HasProfileData),
+        LoopHeaders(std::move(Other.LoopHeaders)),
+        RecursionSet(std::move(Other.RecursionSet)),
+        BBDupThreshold(Other.BBDupThreshold) {}
+
+  // Glue for old PM.
+  bool runImpl(Function &F, TargetLibraryInfo *TLI_, LazyValueInfo *LVI_,
+               bool HasProfileData_, std::unique_ptr<BlockFrequencyInfo> BFI_,
+               std::unique_ptr<BranchProbabilityInfo> BPI_);
+
+  PreservedAnalyses run(Function &F, AnalysisManager<Function> &AM);
+
+  void releaseMemory() {
+    BFI.reset();
+    BPI.reset();
+  }
+
+  void FindLoopHeaders(Function &F);
+  bool ProcessBlock(BasicBlock *BB);
+  bool ThreadEdge(BasicBlock *BB, const SmallVectorImpl<BasicBlock *> &PredBBs,
+                  BasicBlock *SuccBB);
+  bool DuplicateCondBranchOnPHIIntoPred(
+      BasicBlock *BB, const SmallVectorImpl<BasicBlock *> &PredBBs);
+
+  bool
+  ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,
+                                  jumpthreading::PredValueInfo &Result,
+                                  jumpthreading::ConstantPreference Preference,
+                                  Instruction *CxtI = nullptr);
+  bool ProcessThreadableEdges(Value *Cond, BasicBlock *BB,
+                              jumpthreading::ConstantPreference Preference,
+                              Instruction *CxtI = nullptr);
+
+  bool ProcessBranchOnPHI(PHINode *PN);
+  bool ProcessBranchOnXOR(BinaryOperator *BO);
+  bool ProcessImpliedCondition(BasicBlock *BB);
+
+  bool SimplifyPartiallyRedundantLoad(LoadInst *LI);
+  bool TryToUnfoldSelect(CmpInst *CondCmp, BasicBlock *BB);
+  bool TryToUnfoldSelectInCurrBB(BasicBlock *BB);
+
+private:
+  BasicBlock *SplitBlockPreds(BasicBlock *BB, ArrayRef<BasicBlock *> Preds,
+                              const char *Suffix);
+  void UpdateBlockFreqAndEdgeWeight(BasicBlock *PredBB, BasicBlock *BB,
+                                    BasicBlock *NewBB, BasicBlock *SuccBB);
+};
+
+} // end namespace llvm
+
+#endif

lib/Passes/PassBuilder.cpp

@@ -75,6 +75,7 @@
 #include "llvm/Transforms/Scalar/GVN.h"
 #include "llvm/Transforms/Scalar/GuardWidening.h"
 #include "llvm/Transforms/Scalar/IndVarSimplify.h"
+#include "llvm/Transforms/Scalar/JumpThreading.h"
 #include "llvm/Transforms/Scalar/LoopRotation.h"
 #include "llvm/Transforms/Scalar/LoopSimplifyCFG.h"
 #include "llvm/Transforms/Scalar/LowerAtomic.h"

lib/Passes/PassRegistry.def

@@ -130,6 +130,7 @@ FUNCTION_PASS("lower-expect", LowerExpectIntrinsicPass())
 FUNCTION_PASS("guard-widening", GuardWideningPass())
 FUNCTION_PASS("gvn", GVN())
 FUNCTION_PASS("mldst-motion", MergedLoadStoreMotionPass())
+FUNCTION_PASS("jump-threading", JumpThreadingPass())
 FUNCTION_PASS("partially-inline-libcalls", PartiallyInlineLibCallsPass())
 FUNCTION_PASS("lcssa", LCSSAPass())
 FUNCTION_PASS("print", PrintFunctionPass(dbgs()))