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Remove dead code

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35380 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anton Korobeynikov 2007-03-27 12:05:48 +00:00
parent b17b08d1f2
commit dd43321079
1 changed files with 46 additions and 82 deletions
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128
lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
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@ -499,19 +499,15 @@ public:
void visitUnreachable(UnreachableInst &I) { /* noop */ }
// Helpers for visitSwitch
void handleSmallSwitchRange(CaseRec& CR,
bool handleSmallSwitchRange(CaseRec& CR,
CaseRecVector& WorkList,
Value* SV,
MachineBasicBlock* Default);
void handleJTSwitchCase(CaseRec& CR,
bool handleJTSwitchCase(CaseRec& CR,
CaseRecVector& WorkList,
Value* SV,
MachineBasicBlock* Default);
void handleBTSplitSwitchCase(CaseRec& CR,
CaseRecVector& WorkList,
Value* SV,
MachineBasicBlock* Default);
void handleBTSmallSwitchCase(CaseRec& CR,
bool handleBTSplitSwitchCase(CaseRec& CR,
CaseRecVector& WorkList,
Value* SV,
MachineBasicBlock* Default);
@ -1228,10 +1224,17 @@ void SelectionDAGLowering::visitUnwind(UnwindInst &I) {
/// handleSmaaSwitchCaseRange - Emit a series of specific tests (suitable for
/// small case ranges).
void SelectionDAGLowering::handleSmallSwitchRange(CaseRec& CR,
bool SelectionDAGLowering::handleSmallSwitchRange(CaseRec& CR,
CaseRecVector& WorkList,
Value* SV,
MachineBasicBlock* Default) {
Case& BackCase = *(CR.Range.second-1);
// Size is the number of Cases represented by this range.
unsigned Size = CR.Range.second - CR.Range.first;
if (Size >=3)
return false;
// Get the MachineFunction which holds the current MBB. This is used when
// inserting any additional MBBs necessary to represent the switch.
MachineFunction *CurMF = CurMBB->getParent();
@ -1240,8 +1243,6 @@ void SelectionDAGLowering::handleSmallSwitchRange(CaseRec& CR,
MachineBasicBlock *NextBlock = 0;
MachineFunction::iterator BBI = CR.CaseBB;
Case& BackCase = *(CR.Range.second-1);
if (++BBI != CurMBB->getParent()->end())
NextBlock = BBI;
@ -1290,16 +1291,36 @@ void SelectionDAGLowering::handleSmallSwitchRange(CaseRec& CR,
CurBlock = FallThrough;
}
return true;
}
/// handleJTSwitchCase - Emit jumptable for current switch case range
void SelectionDAGLowering::handleJTSwitchCase(CaseRec& CR,
bool SelectionDAGLowering::handleJTSwitchCase(CaseRec& CR,
CaseRecVector& WorkList,
Value* SV,
MachineBasicBlock* Default) {
Case& FrontCase = *CR.Range.first;
Case& BackCase = *(CR.Range.second-1);
// Size is the number of Cases represented by this range.
unsigned Size = CR.Range.second - CR.Range.first;
uint64_t First = cast<ConstantInt>(FrontCase.first)->getSExtValue();
uint64_t Last = cast<ConstantInt>(BackCase.first)->getSExtValue();
if ((!TLI.isOperationLegal(ISD::BR_JT, MVT::Other) &&
!TLI.isOperationLegal(ISD::BRIND, MVT::Other)) ||
Size <= 5)
return false;
double Density = (double)Size / (double)((Last - First) + 1ULL);
if (Density < 0.3125)
return false;
// Get the MachineFunction which holds the current MBB. This is used when
// inserting any additional MBBs necessary to represent the switch.
MachineFunction *CurMF = CurMBB->getParent();
MachineFunction *CurMF = CurMBB->getParent();
// Figure out which block is immediately after the current one.
MachineBasicBlock *NextBlock = 0;
@ -1308,13 +1329,8 @@ void SelectionDAGLowering::handleJTSwitchCase(CaseRec& CR,
if (++BBI != CurMBB->getParent()->end())
NextBlock = BBI;
Case& FrontCase = *CR.Range.first;
Case& BackCase = *(CR.Range.second-1);
const BasicBlock *LLVMBB = CR.CaseBB->getBasicBlock();
uint64_t First = cast<ConstantInt>(FrontCase.first)->getSExtValue();
uint64_t Last = cast<ConstantInt>(BackCase.first)->getSExtValue();
// Create a new basic block to hold the code for loading the address
// of the jump table, and jumping to it. Update successor information;
// we will either branch to the default case for the switch, or the jump
@ -1364,37 +1380,13 @@ void SelectionDAGLowering::handleJTSwitchCase(CaseRec& CR,
visitJumpTableHeader(JT, JTH);
JTCases.push_back(SelectionDAGISel::JumpTableBlock(JTH, JT));
}
/// handleBTSmallSwitchCase - handle leaf in the binary comparison tree. Just
/// emit test.
void SelectionDAGLowering::handleBTSmallSwitchCase(CaseRec& CR,
CaseRecVector& WorkList,
Value* SV,
MachineBasicBlock* Default) {
Case& FrontCase = *CR.Range.first;
// Create a CaseBlock record representing a conditional branch to
// the Case's target mbb if the value being switched on SV is equal
// to C. Otherwise, branch to default.
Constant *C = FrontCase.first;
MachineBasicBlock *Target = FrontCase.second;
SelectionDAGISel::CaseBlock CB(ISD::SETEQ, SV, C, Target, Default,
CR.CaseBB);
// If the MBB representing the leaf node is the current MBB, then just
// call visitSwitchCase to emit the code into the current block.
// Otherwise, push the CaseBlock onto the vector to be later processed
// by SDISel, and insert the node's MBB before the next MBB.
if (CR.CaseBB == CurMBB)
visitSwitchCase(CB);
else
SwitchCases.push_back(CB);
return true;
}
/// handleBTSplitSwitchCase - emit comparison and split binary search tree into
/// 2 subtrees.
void SelectionDAGLowering::handleBTSplitSwitchCase(CaseRec& CR,
bool SelectionDAGLowering::handleBTSplitSwitchCase(CaseRec& CR,
CaseRecVector& WorkList,
Value* SV,
MachineBasicBlock* Default) {
@ -1483,6 +1475,8 @@ void SelectionDAGLowering::handleBTSplitSwitchCase(CaseRec& CR,
visitSwitchCase(CB);
else
SwitchCases.push_back(CB);
return true;
}
void SelectionDAGLowering::visitSwitch(SwitchInst &I) {
@ -1530,51 +1524,21 @@ void SelectionDAGLowering::visitSwitch(SwitchInst &I) {
// Grab a record representing a case range to process off the worklist
CaseRec CR = WorkList.back();
WorkList.pop_back();
Case& FrontCase = *CR.Range.first;
Case& BackCase = *(CR.Range.second-1);
// Figure out which block is immediately after the current one.
NextBlock = 0;
BBI = CR.CaseBB;
if (++BBI != CurMBB->getParent()->end())
NextBlock = BBI;
// Size is the number of Cases represented by this range.
unsigned Size = CR.Range.second - CR.Range.first;
// If the range has few cases (two or less) emit a series of specific
// tests.
if (Size < 3) {
handleSmallSwitchRange(CR, WorkList, SV, Default);
continue;
}
if (handleSmallSwitchRange(CR, WorkList, SV, Default))
continue;
// If the switch has more than 5 blocks, and at least 31.25% dense, and the
// target supports indirect branches, then emit a jump table rather than
// lowering the switch to a binary tree of conditional branches.
if ((TLI.isOperationLegal(ISD::BR_JT, MVT::Other) ||
TLI.isOperationLegal(ISD::BRIND, MVT::Other)) &&
Size > 5) {
uint64_t First = cast<ConstantInt>(FrontCase.first)->getSExtValue();
uint64_t Last = cast<ConstantInt>(BackCase.first)->getSExtValue();
double Density = (double)Size / (double)((Last - First) + 1ULL);
if (Density >= 0.3125) {
handleJTSwitchCase(CR, WorkList, SV, Default);
continue;
}
}
// Emit binary tree. If Size is 1, then we are processing a leaf of the
// binary search tree. Otherwise, we need to pick a pivot, and push left
// and right ranges onto the worklist.
if (Size == 1)
handleBTSmallSwitchCase(CR, WorkList, SV, Default);
else
handleBTSplitSwitchCase(CR, WorkList, SV, Default);
if (handleJTSwitchCase(CR, WorkList, SV, Default))
continue;
// Emit binary tree. We need to pick a pivot, and push left and right ranges
// onto the worklist. Leafs are handled via handleSmallSwitchRange() call.
handleBTSplitSwitchCase(CR, WorkList, SV, Default);
}
}