Revert r200431 due to bot failures.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200434 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -1393,9 +1393,7 @@ SelectionDAGBuilder::EmitBranchForMergedCondition(const Value *Cond,
                                                   MachineBasicBlock *TBB,
                                                   MachineBasicBlock *FBB,
                                                   MachineBasicBlock *CurBB,
-                                                  MachineBasicBlock *SwitchBB,
+                                                  MachineBasicBlock *SwitchBB) {
-                                                  uint32_t TWeight,
-                                                  uint32_t FWeight) {
   const BasicBlock *BB = CurBB->getBasicBlock();
 
   // If the leaf of the tree is a comparison, merge the condition into
@@ -1420,7 +1418,7 @@ SelectionDAGBuilder::EmitBranchForMergedCondition(const Value *Cond,
       }
 
       CaseBlock CB(Condition, BOp->getOperand(0),
-                   BOp->getOperand(1), NULL, TBB, FBB, CurBB, TWeight, FWeight);
+                   BOp->getOperand(1), NULL, TBB, FBB, CurBB);
       SwitchCases.push_back(CB);
       return;
     }
@@ -1428,26 +1426,17 @@ SelectionDAGBuilder::EmitBranchForMergedCondition(const Value *Cond,
 
   // Create a CaseBlock record representing this branch.
   CaseBlock CB(ISD::SETEQ, Cond, ConstantInt::getTrue(*DAG.getContext()),
-               NULL, TBB, FBB, CurBB, TWeight, FWeight);
+               NULL, TBB, FBB, CurBB);
   SwitchCases.push_back(CB);
 }
 
-/// Scale down both weights to fit into uint32_t.
-static void ScaleWeights(uint64_t &NewTrue, uint64_t &NewFalse) {
-  uint64_t NewMax = (NewTrue > NewFalse) ? NewTrue : NewFalse;
-  uint32_t Scale = (NewMax / UINT32_MAX) + 1;
-  NewTrue = NewTrue / Scale;
-  NewFalse = NewFalse / Scale;
-}
-
 /// FindMergedConditions - If Cond is an expression like
 void SelectionDAGBuilder::FindMergedConditions(const Value *Cond,
                                                MachineBasicBlock *TBB,
                                                MachineBasicBlock *FBB,
                                                MachineBasicBlock *CurBB,
                                                MachineBasicBlock *SwitchBB,
-                                               unsigned Opc, uint32_t TWeight,
+                                               unsigned Opc) {
-                                               uint32_t FWeight) {
   // If this node is not part of the or/and tree, emit it as a branch.
   const Instruction *BOp = dyn_cast<Instruction>(Cond);
   if (!BOp || !(isa<BinaryOperator>(BOp) || isa<CmpInst>(BOp)) ||
@@ -1455,8 +1444,7 @@ void SelectionDAGBuilder::FindMergedConditions(const Value *Cond,
       BOp->getParent() != CurBB->getBasicBlock() ||
       !InBlock(BOp->getOperand(0), CurBB->getBasicBlock()) ||
       !InBlock(BOp->getOperand(1), CurBB->getBasicBlock())) {
-    EmitBranchForMergedCondition(Cond, TBB, FBB, CurBB, SwitchBB,
+    EmitBranchForMergedCondition(Cond, TBB, FBB, CurBB, SwitchBB);
-                                 TWeight, FWeight);
     return;
   }
 
@@ -1468,7 +1456,6 @@ void SelectionDAGBuilder::FindMergedConditions(const Value *Cond,
 
   if (Opc == Instruction::Or) {
     // Codegen X | Y as:
-    // BB1:
     //   jmp_if_X TBB
     //   jmp TmpBB
     // TmpBB:
@@ -1476,34 +1463,14 @@ void SelectionDAGBuilder::FindMergedConditions(const Value *Cond,
     //   jmp FBB
     //
 
-    // We have flexibility in setting Prob for BB1 and Prob for TmpBB.
-    // The requirement is that
-    //   TrueProb for BB1 + (FalseProb for BB1 * TrueProb for TmpBB)
-    //     = TrueProb for orignal BB.
-    // Assuming the orignal weights are A and B, one choice is to set BB1's
-    // weights to A and A+2B, and set TmpBB's weights to A and 2B. This choice
-    // assumes that
-    //   TrueProb for BB1 == FalseProb for BB1 * TrueProb for TmpBB.
-    // Another choice is to assume TrueProb for BB1 equals to TrueProb for
-    // TmpBB, but the math is more complicated.
-
-    uint64_t NewTrueWeight = TWeight;
-    uint64_t NewFalseWeight = (uint64_t)TWeight + 2 * (uint64_t)FWeight;
-    ScaleWeights(NewTrueWeight, NewFalseWeight);
     // Emit the LHS condition.
-    FindMergedConditions(BOp->getOperand(0), TBB, TmpBB, CurBB, SwitchBB, Opc,
+    FindMergedConditions(BOp->getOperand(0), TBB, TmpBB, CurBB, SwitchBB, Opc);
-                         NewTrueWeight, NewFalseWeight);
 
-    NewTrueWeight = TWeight;
-    NewFalseWeight = 2 * (uint64_t)FWeight;
-    ScaleWeights(NewTrueWeight, NewFalseWeight);
     // Emit the RHS condition into TmpBB.
-    FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, SwitchBB, Opc,
+    FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, SwitchBB, Opc);
-                         NewTrueWeight, NewFalseWeight);
   } else {
     assert(Opc == Instruction::And && "Unknown merge op!");
     // Codegen X & Y as:
-    // BB1:
     //   jmp_if_X TmpBB
     //   jmp FBB
     // TmpBB:
@@ -1512,28 +1479,11 @@ void SelectionDAGBuilder::FindMergedConditions(const Value *Cond,
     //
     //  This requires creation of TmpBB after CurBB.
 
-    // We have flexibility in setting Prob for BB1 and Prob for TmpBB.
-    // The requirement is that
-    //   FalseProb for BB1 + (TrueProb for BB1 * FalseProb for TmpBB)
-    //     = FalseProb for orignal BB.
-    // Assuming the orignal weights are A and B, one choice is to set BB1's
-    // weights to 2A+B and B, and set TmpBB's weights to 2A and B. This choice
-    // assumes that
-    //   FalseProb for BB1 == TrueProb for BB1 * FalseProb for TmpBB.
-
-    uint64_t NewTrueWeight = 2 * (uint64_t)TWeight + (uint64_t)FWeight;
-    uint64_t NewFalseWeight = FWeight;
-    ScaleWeights(NewTrueWeight, NewFalseWeight);
     // Emit the LHS condition.
-    FindMergedConditions(BOp->getOperand(0), TmpBB, FBB, CurBB, SwitchBB, Opc,
+    FindMergedConditions(BOp->getOperand(0), TmpBB, FBB, CurBB, SwitchBB, Opc);
-                         NewTrueWeight, NewFalseWeight);
 
-    NewTrueWeight = 2 * (uint64_t)TWeight;
-    NewFalseWeight = FWeight;
-    ScaleWeights(NewTrueWeight, NewFalseWeight);
     // Emit the RHS condition into TmpBB.
-    FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, SwitchBB, Opc,
+    FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, SwitchBB, Opc);
-                         NewTrueWeight, NewFalseWeight);
   }
 }
 
@@ -1620,8 +1570,7 @@ void SelectionDAGBuilder::visitBr(const BranchInst &I) {
         (BOp->getOpcode() == Instruction::And ||
          BOp->getOpcode() == Instruction::Or)) {
       FindMergedConditions(BOp, Succ0MBB, Succ1MBB, BrMBB, BrMBB,
-                           BOp->getOpcode(), getEdgeWeight(BrMBB, Succ0MBB),
+                           BOp->getOpcode());
-                           getEdgeWeight(BrMBB, Succ1MBB));
       // If the compares in later blocks need to use values not currently
       // exported from this block, export them now.  This block should always
       // be the first entry.

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h

@@ -612,13 +612,11 @@ public:
 
   void FindMergedConditions(const Value *Cond, MachineBasicBlock *TBB,
                             MachineBasicBlock *FBB, MachineBasicBlock *CurBB,
-                            MachineBasicBlock *SwitchBB, unsigned Opc,
+                            MachineBasicBlock *SwitchBB, unsigned Opc);
-                            uint32_t TW, uint32_t FW);
   void EmitBranchForMergedCondition(const Value *Cond, MachineBasicBlock *TBB,
                                     MachineBasicBlock *FBB,
                                     MachineBasicBlock *CurBB,
-                                    MachineBasicBlock *SwitchBB,
+                                    MachineBasicBlock *SwitchBB);
-                                    uint32_t TW, uint32_t FW);
   bool ShouldEmitAsBranches(const std::vector<CaseBlock> &Cases);
   bool isExportableFromCurrentBlock(const Value *V, const BasicBlock *FromBB);
   void CopyToExportRegsIfNeeded(const Value *V);

test/CodeGen/X86/MachineBranchProb.ll

@@ -1,34 +0,0 @@
-; RUN: llc < %s -mtriple=x86_64-apple-darwin -print-machineinstrs=expand-isel-pseudos -o /dev/null 2>&1 | FileCheck %s
-
-;; Make sure a transformation in SelectionDAGBuilder that converts "or + br" to
-;; two branches correctly updates the branch probability.
-
-@max_regno = common global i32 0, align 4
-
-define void @test(i32* %old, i32 %final) {
-for.cond:
-  br label %for.cond2
-
-for.cond2:                                        ; preds = %for.inc, %for.cond
-  %i.1 = phi i32 [ %inc19, %for.inc ], [ 0, %for.cond ]
-  %bit.0 = phi i32 [ %shl, %for.inc ], [ 1, %for.cond ]
-  %tobool = icmp eq i32 %bit.0, 0
-  %v3 = load i32* @max_regno, align 4
-  %cmp4 = icmp eq i32 %i.1, %v3
-  %or.cond = or i1 %tobool, %cmp4
-  br i1 %or.cond, label %for.inc20, label %for.inc, !prof !0
-; CHECK: BB#1: derived from LLVM BB %for.cond2
-; CHECK: Successors according to CFG: BB#3(28004359) BB#4(1101746182)
-; CHECK: BB#4: derived from LLVM BB %for.cond2
-; CHECK: Successors according to CFG: BB#3(56008718) BB#2(2147483647)
-
-for.inc:                                          ; preds = %for.cond2
-  %shl = shl i32 %bit.0, 1
-  %inc19 = add nsw i32 %i.1, 1
-  br label %for.cond2
-
-for.inc20:                                        ; preds = %for.cond2
-  ret void
-}
-
-!0 = metadata !{metadata !"branch_weights", i32 112017436, i32 -735157296}