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-rw-r--r--lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp71
-rw-r--r--lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h6
-rw-r--r--test/CodeGen/X86/MachineBranchProb.ll34
3 files changed, 12 insertions, 99 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index c177038102..a561c5190a 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1393,9 +1393,7 @@ SelectionDAGBuilder::EmitBranchForMergedCondition(const Value *Cond,
MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
MachineBasicBlock *CurBB,
- MachineBasicBlock *SwitchBB,
- uint32_t TWeight,
- uint32_t FWeight) {
+ MachineBasicBlock *SwitchBB) {
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,
- uint32_t FWeight) {
+ unsigned Opc) {
// 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,
- TWeight, FWeight);
+ EmitBranchForMergedCondition(Cond, TBB, FBB, CurBB, SwitchBB);
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,
- NewTrueWeight, NewFalseWeight);
+ FindMergedConditions(BOp->getOperand(0), TBB, TmpBB, CurBB, SwitchBB, Opc);
- 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,
- NewTrueWeight, NewFalseWeight);
+ FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, SwitchBB, Opc);
} 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,
- NewTrueWeight, NewFalseWeight);
+ FindMergedConditions(BOp->getOperand(0), TmpBB, FBB, CurBB, SwitchBB, Opc);
- 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,
- NewTrueWeight, NewFalseWeight);
+ FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, SwitchBB, Opc);
}
}
@@ -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),
- getEdgeWeight(BrMBB, Succ1MBB));
+ BOp->getOpcode());
// 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.
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
index a8c6ab77c7..d32d13f343 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
+++ b/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,
- uint32_t TW, uint32_t FW);
+ MachineBasicBlock *SwitchBB, unsigned Opc);
void EmitBranchForMergedCondition(const Value *Cond, MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
MachineBasicBlock *CurBB,
- MachineBasicBlock *SwitchBB,
- uint32_t TW, uint32_t FW);
+ MachineBasicBlock *SwitchBB);
bool ShouldEmitAsBranches(const std::vector<CaseBlock> &Cases);
bool isExportableFromCurrentBlock(const Value *V, const BasicBlock *FromBB);
void CopyToExportRegsIfNeeded(const Value *V);
diff --git a/test/CodeGen/X86/MachineBranchProb.ll b/test/CodeGen/X86/MachineBranchProb.ll
deleted file mode 100644
index 9c6b26dc3d..0000000000
--- a/test/CodeGen/X86/MachineBranchProb.ll
+++ /dev/null
@@ -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}
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-09 05:40:13 +0000