Let SelectionDAG start to use probability-based interface to add successors.

The patch in http://reviews.llvm.org/D13745 is broken into four parts:

1. New interfaces without functional changes.
2. Use new interfaces in SelectionDAG, while in other passes treat probabilities
as weights.
3. Use new interfaces in all other passes.
4. Remove old interfaces.

This the second patch above. In this patch SelectionDAG starts to use
probability-based interfaces in MBB to add successors but other MC passes are
still using weight-based interfaces. Therefore, we need to maintain correct
weight list in MBB even when probability-based interfaces are used. This is
done by updating weight list in probability-based interfaces by treating the
numerator of probabilities as weights. This change affects many test cases
that check successor weight values. I will update those test cases once this
patch looks good to you.


Differential revision: http://reviews.llvm.org/D14361

llvm-svn: 253965

1 files changed, 38 insertions, 36 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index 321e18d682a..1171f0aad00 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -154,39 +154,39 @@ private:
       unsigned JTCasesIndex;
       unsigned BTCasesIndex;
     };
-    uint32_t Weight;
+    BranchProbability Prob;
 
     static CaseCluster range(const ConstantInt *Low, const ConstantInt *High,
-                             MachineBasicBlock *MBB, uint32_t Weight) {
+                             MachineBasicBlock *MBB, BranchProbability Prob) {
       CaseCluster C;
       C.Kind = CC_Range;
       C.Low = Low;
       C.High = High;
       C.MBB = MBB;
-      C.Weight = Weight;
+      C.Prob = Prob;
       return C;
     }
 
     static CaseCluster jumpTable(const ConstantInt *Low,
                                  const ConstantInt *High, unsigned JTCasesIndex,
-                                 uint32_t Weight) {
+                                 BranchProbability Prob) {
       CaseCluster C;
       C.Kind = CC_JumpTable;
       C.Low = Low;
       C.High = High;
       C.JTCasesIndex = JTCasesIndex;
-      C.Weight = Weight;
+      C.Prob = Prob;
       return C;
     }
 
     static CaseCluster bitTests(const ConstantInt *Low, const ConstantInt *High,
-                                unsigned BTCasesIndex, uint32_t Weight) {
+                                unsigned BTCasesIndex, BranchProbability Prob) {
       CaseCluster C;
       C.Kind = CC_BitTests;
       C.Low = Low;
       C.High = High;
       C.BTCasesIndex = BTCasesIndex;
-      C.Weight = Weight;
+      C.Prob = Prob;
       return C;
     }
   };
@@ -198,13 +198,13 @@ private:
     uint64_t Mask;
     MachineBasicBlock* BB;
     unsigned Bits;
-    uint32_t ExtraWeight;
+    BranchProbability ExtraProb;
 
     CaseBits(uint64_t mask, MachineBasicBlock* bb, unsigned bits,
-             uint32_t Weight):
-      Mask(mask), BB(bb), Bits(bits), ExtraWeight(Weight) { }
+             BranchProbability Prob):
+      Mask(mask), BB(bb), Bits(bits), ExtraProb(Prob) { }
 
-    CaseBits() : Mask(0), BB(nullptr), Bits(0), ExtraWeight(0) {}
+    CaseBits() : Mask(0), BB(nullptr), Bits(0) {}
   };
 
   typedef std::vector<CaseBits> CaseBitsVector;
@@ -217,13 +217,13 @@ private:
   /// blocks needed by multi-case switch statements.
   struct CaseBlock {
     CaseBlock(ISD::CondCode cc, const Value *cmplhs, const Value *cmprhs,
-              const Value *cmpmiddle,
-              MachineBasicBlock *truebb, MachineBasicBlock *falsebb,
-              MachineBasicBlock *me,
-              uint32_t trueweight = 0, uint32_t falseweight = 0)
-      : CC(cc), CmpLHS(cmplhs), CmpMHS(cmpmiddle), CmpRHS(cmprhs),
-        TrueBB(truebb), FalseBB(falsebb), ThisBB(me),
-        TrueWeight(trueweight), FalseWeight(falseweight) { }
+              const Value *cmpmiddle, MachineBasicBlock *truebb,
+              MachineBasicBlock *falsebb, MachineBasicBlock *me,
+              BranchProbability trueprob = BranchProbability::getUnknown(),
+              BranchProbability falseprob = BranchProbability::getUnknown())
+        : CC(cc), CmpLHS(cmplhs), CmpMHS(cmpmiddle), CmpRHS(cmprhs),
+          TrueBB(truebb), FalseBB(falsebb), ThisBB(me), TrueProb(trueprob),
+          FalseProb(falseprob) {}
 
     // CC - the condition code to use for the case block's setcc node
     ISD::CondCode CC;
@@ -239,8 +239,8 @@ private:
     // ThisBB - the block into which to emit the code for the setcc and branches
     MachineBasicBlock *ThisBB;
 
-    // TrueWeight/FalseWeight - branch weights.
-    uint32_t TrueWeight, FalseWeight;
+    // TrueProb/FalseProb - branch weights.
+    BranchProbability TrueProb, FalseProb;
   };
 
   struct JumpTable {
@@ -272,12 +272,12 @@ private:
 
   struct BitTestCase {
     BitTestCase(uint64_t M, MachineBasicBlock* T, MachineBasicBlock* Tr,
-                uint32_t Weight):
-      Mask(M), ThisBB(T), TargetBB(Tr), ExtraWeight(Weight) { }
+                BranchProbability Prob):
+      Mask(M), ThisBB(T), TargetBB(Tr), ExtraProb(Prob) { }
     uint64_t Mask;
     MachineBasicBlock *ThisBB;
     MachineBasicBlock *TargetBB;
-    uint32_t ExtraWeight;
+    BranchProbability ExtraProb;
   };
 
   typedef SmallVector<BitTestCase, 3> BitTestInfo;
@@ -285,10 +285,10 @@ private:
   struct BitTestBlock {
     BitTestBlock(APInt F, APInt R, const Value *SV, unsigned Rg, MVT RgVT,
                  bool E, bool CR, MachineBasicBlock *P, MachineBasicBlock *D,
-                 BitTestInfo C, uint32_t W)
+                 BitTestInfo C, BranchProbability Pr)
         : First(F), Range(R), SValue(SV), Reg(Rg), RegVT(RgVT), Emitted(E),
           ContiguousRange(CR), Parent(P), Default(D), Cases(std::move(C)),
-          Weight(W), DefaultWeight(0) {}
+          Prob(Pr) {}
     APInt First;
     APInt Range;
     const Value *SValue;
@@ -299,8 +299,8 @@ private:
     MachineBasicBlock *Parent;
     MachineBasicBlock *Default;
     BitTestInfo Cases;
-    uint32_t Weight;
-    uint32_t DefaultWeight;
+    BranchProbability Prob;
+    BranchProbability DefaultProb;
   };
 
   /// Minimum jump table density, in percent.
@@ -342,7 +342,7 @@ private:
     CaseClusterIt LastCluster;
     const ConstantInt *GE;
     const ConstantInt *LT;
-    uint32_t DefaultWeight;
+    BranchProbability DefaultProb;
   };
   typedef SmallVector<SwitchWorkListItem, 4> SwitchWorkList;
 
@@ -694,13 +694,13 @@ public:
   void FindMergedConditions(const Value *Cond, MachineBasicBlock *TBB,
                             MachineBasicBlock *FBB, MachineBasicBlock *CurBB,
                             MachineBasicBlock *SwitchBB,
-                            Instruction::BinaryOps Opc,
-                            uint32_t TW, uint32_t FW);
+                            Instruction::BinaryOps Opc, BranchProbability TW,
+                            BranchProbability FW);
   void EmitBranchForMergedCondition(const Value *Cond, MachineBasicBlock *TBB,
                                     MachineBasicBlock *FBB,
                                     MachineBasicBlock *CurBB,
                                     MachineBasicBlock *SwitchBB,
-                                    uint32_t TW, uint32_t FW);
+                                    BranchProbability TW, BranchProbability FW);
   bool ShouldEmitAsBranches(const std::vector<CaseBlock> &Cases);
   bool isExportableFromCurrentBlock(const Value *V, const BasicBlock *FromBB);
   void CopyToExportRegsIfNeeded(const Value *V);
@@ -744,10 +744,12 @@ private:
   void visitTerminatePad(const TerminatePadInst &TPI);
   void visitCleanupPad(const CleanupPadInst &CPI);
 
-  uint32_t getEdgeWeight(const MachineBasicBlock *Src,
-                         const MachineBasicBlock *Dst) const;
-  void addSuccessorWithWeight(MachineBasicBlock *Src, MachineBasicBlock *Dst,
-                              uint32_t Weight = 0);
+  BranchProbability getEdgeProbability(const MachineBasicBlock *Src,
+                                       const MachineBasicBlock *Dst) const;
+  void addSuccessorWithProb(
+      MachineBasicBlock *Src, MachineBasicBlock *Dst,
+      BranchProbability Prob = BranchProbability::getUnknown());
+
 public:
   void visitSwitchCase(CaseBlock &CB,
                        MachineBasicBlock *SwitchBB);
@@ -757,7 +759,7 @@ public:
   void visitBitTestHeader(BitTestBlock &B, MachineBasicBlock *SwitchBB);
   void visitBitTestCase(BitTestBlock &BB,
                         MachineBasicBlock* NextMBB,
-                        uint32_t BranchWeightToNext,
+                        BranchProbability BranchProbToNext,
                         unsigned Reg,
                         BitTestCase &B,
                         MachineBasicBlock *SwitchBB);