[NFC] Encapsulate work with BlockColors in LoopSafetyInfo

llvm-svn: 344590

llvm/include/llvm/Analysis/MustExecute.h

@@ -49,6 +49,9 @@ class LoopSafetyInfo {
                                // may throw.
   bool HeaderMayThrow = false; // Same as previous, but specific to loop header
 
+  // Used to update funclet bundle operands.
+  DenseMap<BasicBlock *, ColorVector> BlockColors;
+
   /// Collect all blocks from \p CurLoop which lie on all possible paths from
   /// the header of \p CurLoop (inclusive) to BB (exclusive) into the set
   /// \p Predecessors. If \p BB is the header, \p Predecessors will be empty.
@@ -56,9 +59,16 @@ class LoopSafetyInfo {
       const Loop *CurLoop, const BasicBlock *BB,
       SmallPtrSetImpl<const BasicBlock *> &Predecessors) const;
 
+protected:
+  /// Computes block colors.
+  void computeBlockColors(const Loop *CurLoop);
+
 public:
-  // Used to update funclet bundle operands.
+  /// Returns block colors map that is used to update funclet operand bundles.
-  DenseMap<BasicBlock *, ColorVector> BlockColors;
+  const DenseMap<BasicBlock *, ColorVector> &getBlockColors() const;
+
+  /// Copy colors of block \p Old into the block \p New.
+  void copyColors(BasicBlock *New, BasicBlock *Old);
 
   /// Returns true iff the header block of the loop for which this info is
   /// calculated contains an instruction that may throw or otherwise exit
@@ -83,7 +93,7 @@ public:
   /// as argument. Updates safety information in LoopSafetyInfo argument.
   /// Note: This is defined to clear and reinitialize an already initialized
   /// LoopSafetyInfo.  Some callers rely on this fact.
-  void computeLoopSafetyInfo(Loop *);
+  void computeLoopSafetyInfo(const Loop *CurLoop);
 
   /// Returns true if the instruction in a loop is guaranteed to execute at
   /// least once (under the assumption that the loop is entered).

llvm/lib/Analysis/MustExecute.cpp

@@ -22,6 +22,17 @@
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
+const DenseMap<BasicBlock *, ColorVector> &
+LoopSafetyInfo::getBlockColors() const {
+  return BlockColors;
+}
+
+void LoopSafetyInfo::copyColors(BasicBlock *New, BasicBlock *Old) {
+  ColorVector &ColorsForNewBlock = BlockColors[New];
+  ColorVector &ColorsForOldBlock = BlockColors[Old];
+  ColorsForNewBlock = ColorsForOldBlock;
+}
+
 bool LoopSafetyInfo::headerMayThrow() const {
   return HeaderMayThrow;
 }
@@ -35,7 +46,7 @@ bool LoopSafetyInfo::anyBlockMayThrow() const {
   return MayThrow;
 }
 
-void LoopSafetyInfo::computeLoopSafetyInfo(Loop *CurLoop) {
+void LoopSafetyInfo::computeLoopSafetyInfo(const Loop *CurLoop) {
   assert(CurLoop != nullptr && "CurLoop can't be null");
   BasicBlock *Header = CurLoop->getHeader();
   // Iterate over header and compute safety info.
@@ -51,6 +62,10 @@ void LoopSafetyInfo::computeLoopSafetyInfo(Loop *CurLoop) {
        (BB != BBE) && !MayThrow; ++BB)
     MayThrow |= !isGuaranteedToTransferExecutionToSuccessor(*BB);
 
+  computeBlockColors(CurLoop);
+}
+
+void LoopSafetyInfo::computeBlockColors(const Loop *CurLoop) {
   // Compute funclet colors if we might sink/hoist in a function with a funclet
   // personality routine.
   Function *Fn = CurLoop->getHeader()->getParent();

llvm/lib/Transforms/Scalar/LICM.cpp

@@ -798,7 +798,7 @@ static bool isFreeInLoop(const Instruction &I, const Loop *CurLoop,
 static bool isNotUsedOrFreeInLoop(const Instruction &I, const Loop *CurLoop,
                                   const LoopSafetyInfo *SafetyInfo,
                                   TargetTransformInfo *TTI, bool &FreeInLoop) {
-  const auto &BlockColors = SafetyInfo->BlockColors;
+  const auto &BlockColors = SafetyInfo->getBlockColors();
   bool IsFree = isFreeInLoop(I, CurLoop, TTI);
   for (const User *U : I.users()) {
     const Instruction *UI = cast<Instruction>(U);
@@ -833,7 +833,7 @@ CloneInstructionInExitBlock(Instruction &I, BasicBlock &ExitBlock, PHINode &PN,
                             const LoopSafetyInfo *SafetyInfo) {
   Instruction *New;
   if (auto *CI = dyn_cast<CallInst>(&I)) {
-    const auto &BlockColors = SafetyInfo->BlockColors;
+    const auto &BlockColors = SafetyInfo->getBlockColors();
 
     // Sinking call-sites need to be handled differently from other
     // instructions.  The cloned call-site needs a funclet bundle operand
@@ -913,7 +913,7 @@ static bool canSplitPredecessors(PHINode *PN, LoopSafetyInfo *SafetyInfo) {
   // it require updating BlockColors for all offspring blocks accordingly. By
   // skipping such corner case, we can make updating BlockColors after splitting
   // predecessor fairly simple.
-  if (!SafetyInfo->BlockColors.empty() && BB->getFirstNonPHI()->isEHPad())
+  if (!SafetyInfo->getBlockColors().empty() && BB->getFirstNonPHI()->isEHPad())
     return false;
   for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
     BasicBlock *BBPred = *PI;
@@ -967,7 +967,7 @@ static void splitPredecessorsOfLoopExit(PHINode *PN, DominatorTree *DT,
   // LE:
   //   %p = phi [%p1, %LE.split], [%p2, %LE.split2]
   //
-  auto &BlockColors = SafetyInfo->BlockColors;
+  const auto &BlockColors = SafetyInfo->getBlockColors();
   SmallSetVector<BasicBlock *, 8> PredBBs(pred_begin(ExitBB), pred_end(ExitBB));
   while (!PredBBs.empty()) {
     BasicBlock *PredBB = *PredBBs.begin();
@@ -979,14 +979,11 @@ static void splitPredecessorsOfLoopExit(PHINode *PN, DominatorTree *DT,
       // Since we do not allow splitting EH-block with BlockColors in
       // canSplitPredecessors(), we can simply assign predecessor's color to
       // the new block.
-      if (!BlockColors.empty()) {
+      if (!BlockColors.empty())
         // Grab a reference to the ColorVector to be inserted before getting the
         // reference to the vector we are copying because inserting the new
         // element in BlockColors might cause the map to be reallocated.
-        ColorVector &ColorsForNewBlock = BlockColors[NewPred];
+        SafetyInfo->copyColors(NewPred, PredBB);
-        ColorVector &ColorsForOldBlock = BlockColors[PredBB];
-        ColorsForNewBlock = ColorsForOldBlock;
-      }
     }
     PredBBs.remove(PredBB);
   }