[PM] Port instcombine to the new pass manager!

This is exciting as this is a much more involved port. This is
a complex, existing transformation pass. All of the core logic is shared
between both old and new pass managers. Only the access to the analyses
is separate because the actual techniques are separate. This also uses
a bunch of different and interesting analyses and is the first time
where we need to use an analysis across an IR layer.

This also paves the way to expose instcombine utility functions. I've
got a static function that implements the core pass logic over
a function which might be mildly interesting, but more interesting is
likely exposing a routine which just uses instructions *already in* the
worklist and combines until empty.

I've switched one of my favorite instcombine tests to run with both as
well to make sure this keeps working.

llvm-svn: 226987

3 files changed, 65 insertions, 143 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
index cd9c9e9d5b5..d12ee09d52f 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -15,7 +15,6 @@
 #ifndef LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINEINTERNAL_H
 #define LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINEINTERNAL_H
 
-#include "InstCombineWorklist.h"
 #include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/TargetFolder.h"
@@ -27,6 +26,7 @@
 #include "llvm/IR/Operator.h"
 #include "llvm/IR/PatternMatch.h"
 #include "llvm/Pass.h"
+#include "llvm/Transforms/InstCombine/InstCombineWorklist.h"
 
 #define DEBUG_TYPE "instcombine"
 
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineWorklist.h b/llvm/lib/Transforms/InstCombine/InstCombineWorklist.h
deleted file mode 100644
index 8d857d0f8e0..00000000000
--- a/llvm/lib/Transforms/InstCombine/InstCombineWorklist.h
+++ /dev/null
@@ -1,107 +0,0 @@
-//===- InstCombineWorklist.h - Worklist for InstCombine pass ----*- C++ -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINEWORKLIST_H
-#define LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINEWORKLIST_H
-
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/IR/Instruction.h"
-#include "llvm/Support/Compiler.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/Support/raw_ostream.h"
-
-#define DEBUG_TYPE "instcombine"
-
-namespace llvm {
-
-/// InstCombineWorklist - This is the worklist management logic for
-/// InstCombine.
-class LLVM_LIBRARY_VISIBILITY InstCombineWorklist {
-  SmallVector<Instruction*, 256> Worklist;
-  DenseMap<Instruction*, unsigned> WorklistMap;
-
-  void operator=(const InstCombineWorklist&RHS) LLVM_DELETED_FUNCTION;
-  InstCombineWorklist(const InstCombineWorklist&) LLVM_DELETED_FUNCTION;
-public:
-  InstCombineWorklist() {}
-
-  bool isEmpty() const { return Worklist.empty(); }
-
-  /// Add - Add the specified instruction to the worklist if it isn't already
-  /// in it.
-  void Add(Instruction *I) {
-    if (WorklistMap.insert(std::make_pair(I, Worklist.size())).second) {
-      DEBUG(dbgs() << "IC: ADD: " << *I << '\n');
-      Worklist.push_back(I);
-    }
-  }
-
-  void AddValue(Value *V) {
-    if (Instruction *I = dyn_cast<Instruction>(V))
-      Add(I);
-  }
-
-  /// AddInitialGroup - Add the specified batch of stuff in reverse order.
-  /// which should only be done when the worklist is empty and when the group
-  /// has no duplicates.
-  void AddInitialGroup(Instruction *const *List, unsigned NumEntries) {
-    assert(Worklist.empty() && "Worklist must be empty to add initial group");
-    Worklist.reserve(NumEntries+16);
-    WorklistMap.resize(NumEntries);
-    DEBUG(dbgs() << "IC: ADDING: " << NumEntries << " instrs to worklist\n");
-    for (unsigned Idx = 0; NumEntries; --NumEntries) {
-      Instruction *I = List[NumEntries-1];
-      WorklistMap.insert(std::make_pair(I, Idx++));
-      Worklist.push_back(I);
-    }
-  }
-
-  // Remove - remove I from the worklist if it exists.
-  void Remove(Instruction *I) {
-    DenseMap<Instruction*, unsigned>::iterator It = WorklistMap.find(I);
-    if (It == WorklistMap.end()) return; // Not in worklist.
-
-    // Don't bother moving everything down, just null out the slot.
-    Worklist[It->second] = nullptr;
-
-    WorklistMap.erase(It);
-  }
-
-  Instruction *RemoveOne() {
-    Instruction *I = Worklist.pop_back_val();
-    WorklistMap.erase(I);
-    return I;
-  }
-
-  /// AddUsersToWorkList - When an instruction is simplified, add all users of
-  /// the instruction to the work lists because they might get more simplified
-  /// now.
-  ///
-  void AddUsersToWorkList(Instruction &I) {
-    for (User *U : I.users())
-      Add(cast<Instruction>(U));
-  }
-
-
-  /// Zap - check that the worklist is empty and nuke the backing store for
-  /// the map if it is large.
-  void Zap() {
-    assert(WorklistMap.empty() && "Worklist empty, but map not?");
-
-    // Do an explicit clear, this shrinks the map if needed.
-    WorklistMap.clear();
-  }
-};
-
-} // end namespace llvm.
-
-#undef DEBUG_TYPE
-
-#endif
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index d27801b85b5..9a42d4580b8 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -33,7 +33,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/InstCombine/InstCombine.h"
 #include "InstCombineInternal.h"
 #include "llvm-c/Initialization.h"
 #include "llvm/ADT/SmallPtrSet.h"
@@ -45,6 +45,7 @@
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/MemoryBuiltins.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/DataLayout.h"
@@ -55,7 +56,7 @@
 #include "llvm/IR/ValueHandle.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
-#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/Transforms/Scalar.h"
 #include "llvm/Transforms/Utils/Local.h"
 #include <algorithm>
 #include <climits>
@@ -2922,6 +2923,66 @@ static bool prepareICWorklistFromFunction(Function &F, const DataLayout *DL,
   return MadeIRChange;
 }
 
+static bool combineInstructionsOverFunction(
+    Function &F, InstCombineWorklist &Worklist, AssumptionCache &AC,
+    TargetLibraryInfo &TLI, DominatorTree &DT, const DataLayout *DL = nullptr,
+    LoopInfo *LI = nullptr) {
+  // Minimizing size?
+  bool MinimizeSize = F.getAttributes().hasAttribute(
+      AttributeSet::FunctionIndex, Attribute::MinSize);
+
+  /// Builder - This is an IRBuilder that automatically inserts new
+  /// instructions into the worklist when they are created.
+  IRBuilder<true, TargetFolder, InstCombineIRInserter> Builder(
+      F.getContext(), TargetFolder(DL), InstCombineIRInserter(Worklist, &AC));
+
+  // Lower dbg.declare intrinsics otherwise their value may be clobbered
+  // by instcombiner.
+  bool DbgDeclaresChanged = LowerDbgDeclare(F);
+
+  // Iterate while there is work to do.
+  int Iteration = 0;
+  for (;;) {
+    ++Iteration;
+    DEBUG(dbgs() << "\n\nINSTCOMBINE ITERATION #" << Iteration << " on "
+                 << F.getName() << "\n");
+
+    bool Changed = false;
+    if (prepareICWorklistFromFunction(F, DL, &TLI, Worklist))
+      Changed = true;
+
+    InstCombiner IC(Worklist, &Builder, MinimizeSize, &AC, &TLI, &DT, DL, LI);
+    if (IC.run())
+      Changed = true;
+
+    if (!Changed)
+      break;
+  }
+
+  return DbgDeclaresChanged || Iteration > 1;
+}
+
+PreservedAnalyses InstCombinePass::run(Function &F,
+                                       AnalysisManager<Function> *AM) {
+  auto *DL = F.getParent()->getDataLayout();
+
+  auto &AC = AM->getResult<AssumptionAnalysis>(F);
+  auto &DT = AM->getResult<DominatorTreeAnalysis>(F);
+  auto &TLI = AM->getResult<TargetLibraryAnalysis>(F);
+
+  auto *LI = AM->getCachedResult<LoopAnalysis>(F);
+
+  if (!combineInstructionsOverFunction(F, Worklist, AC, TLI, DT, DL, LI))
+    // No changes, all analyses are preserved.
+    return PreservedAnalyses::all();
+
+  // Mark all the analyses that instcombine updates as preserved.
+  // FIXME: Need a way to preserve CFG analyses here!
+  PreservedAnalyses PA;
+  PA.preserve<DominatorTreeAnalysis>();
+  return PA;
+}
+
 namespace {
 /// \brief The legacy pass manager's instcombine pass.
 ///
@@ -2954,10 +3015,6 @@ bool InstructionCombiningPass::runOnFunction(Function &F) {
   if (skipOptnoneFunction(F))
     return false;
 
-  // Lower dbg.declare intrinsics otherwise their value may be clobbered
-  // by instcombiner.
-  bool DbgDeclaresChanged = LowerDbgDeclare(F);
-
   // Required analyses.
   auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
   auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
@@ -2969,35 +3026,7 @@ bool InstructionCombiningPass::runOnFunction(Function &F) {
   auto *LIWP = getAnalysisIfAvailable<LoopInfoWrapperPass>();
   auto *LI = LIWP ? &LIWP->getLoopInfo() : nullptr;
 
-  // Minimizing size?
-  bool MinimizeSize = F.getAttributes().hasAttribute(
-      AttributeSet::FunctionIndex, Attribute::MinSize);
-
-  /// Builder - This is an IRBuilder that automatically inserts new
-  /// instructions into the worklist when they are created.
-  IRBuilder<true, TargetFolder, InstCombineIRInserter> Builder(
-      F.getContext(), TargetFolder(DL), InstCombineIRInserter(Worklist, &AC));
-
-  // Iterate while there is work to do.
-  int Iteration = 0;
-  for (;;) {
-    ++Iteration;
-    DEBUG(dbgs() << "\n\nINSTCOMBINE ITERATION #" << Iteration << " on "
-                 << F.getName() << "\n");
-
-    bool Changed = false;
-    if (prepareICWorklistFromFunction(F, DL, &TLI, Worklist))
-      Changed = true;
-
-    InstCombiner IC(Worklist, &Builder, MinimizeSize, &AC, &TLI, &DT, DL, LI);
-    if (IC.run())
-      Changed = true;
-
-    if (!Changed)
-      break;
-  }
-
-  return DbgDeclaresChanged || Iteration > 1;
+  return combineInstructionsOverFunction(F, Worklist, AC, TLI, DT, DL, LI);
 }
 
 char InstructionCombiningPass::ID = 0;