mirror of
https://github.com/c64scene-ar/llvm-6502.git
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Split big monster into small helpers. No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35379 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anton Korobeynikov
parent
0b57a76bc8
commit
b17b08d1f2
@ -384,6 +384,8 @@ class SelectionDAGLowering {
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/// processed at this point in the binary search tree.
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CaseRange Range;
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};
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typedef std::vector<CaseRec> CaseRecVector;
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/// The comparison function for sorting Case values.
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struct CaseCmp {
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@ -496,7 +498,23 @@ public:
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void visitSwitch(SwitchInst &I);
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void visitUnreachable(UnreachableInst &I) { /* noop */ }
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// Helper for visitSwitch
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// Helpers for visitSwitch
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void handleSmallSwitchRange(CaseRec& CR,
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CaseRecVector& WorkList,
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Value* SV,
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MachineBasicBlock* Default);
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void handleJTSwitchCase(CaseRec& CR,
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CaseRecVector& WorkList,
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Value* SV,
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MachineBasicBlock* Default);
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void handleBTSplitSwitchCase(CaseRec& CR,
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CaseRecVector& WorkList,
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Value* SV,
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MachineBasicBlock* Default);
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void handleBTSmallSwitchCase(CaseRec& CR,
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CaseRecVector& WorkList,
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Value* SV,
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MachineBasicBlock* Default);
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void visitSwitchCase(SelectionDAGISel::CaseBlock &CB);
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void visitJumpTable(SelectionDAGISel::JumpTable &JT);
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void visitJumpTableHeader(SelectionDAGISel::JumpTable &JT,
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@ -1208,6 +1226,265 @@ void SelectionDAGLowering::visitInvoke(InvokeInst &I, bool AsTerminator) {
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void SelectionDAGLowering::visitUnwind(UnwindInst &I) {
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}
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/// handleSmaaSwitchCaseRange - Emit a series of specific tests (suitable for
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/// small case ranges).
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void SelectionDAGLowering::handleSmallSwitchRange(CaseRec& CR,
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CaseRecVector& WorkList,
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Value* SV,
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MachineBasicBlock* Default) {
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// Get the MachineFunction which holds the current MBB. This is used when
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// inserting any additional MBBs necessary to represent the switch.
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MachineFunction *CurMF = CurMBB->getParent();
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// Figure out which block is immediately after the current one.
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MachineBasicBlock *NextBlock = 0;
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MachineFunction::iterator BBI = CR.CaseBB;
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Case& BackCase = *(CR.Range.second-1);
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if (++BBI != CurMBB->getParent()->end())
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NextBlock = BBI;
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// TODO: If any two of the cases has the same destination, and if one value
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// is the same as the other, but has one bit unset that the other has set,
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// use bit manipulation to do two compares at once. For example:
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// "if (X == 6 || X == 4)" -> "if ((X|2) == 6)"
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// Rearrange the case blocks so that the last one falls through if possible.
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if (NextBlock && Default != NextBlock && BackCase.second != NextBlock) {
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// The last case block won't fall through into 'NextBlock' if we emit the
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// branches in this order. See if rearranging a case value would help.
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for (CaseItr I = CR.Range.first, E = CR.Range.second-1; I != E; ++I) {
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if (I->second == NextBlock) {
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std::swap(*I, BackCase);
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break;
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}
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}
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}
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// Create a CaseBlock record representing a conditional branch to
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// the Case's target mbb if the value being switched on SV is equal
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// to C.
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MachineBasicBlock *CurBlock = CR.CaseBB;
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for (CaseItr I = CR.Range.first, E = CR.Range.second; I != E; ++I) {
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MachineBasicBlock *FallThrough;
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if (I != E-1) {
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FallThrough = new MachineBasicBlock(CurBlock->getBasicBlock());
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CurMF->getBasicBlockList().insert(BBI, FallThrough);
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} else {
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// If the last case doesn't match, go to the default block.
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FallThrough = Default;
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}
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SelectionDAGISel::CaseBlock CB(ISD::SETEQ, SV, I->first,
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I->second, FallThrough, CurBlock);
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// If emitting the first comparison, just call visitSwitchCase to emit the
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// code into the current block. Otherwise, push the CaseBlock onto the
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// vector to be later processed by SDISel, and insert the node's MBB
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// before the next MBB.
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if (CurBlock == CurMBB)
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visitSwitchCase(CB);
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else
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SwitchCases.push_back(CB);
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CurBlock = FallThrough;
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}
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}
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/// handleJTSwitchCase - Emit jumptable for current switch case range
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void SelectionDAGLowering::handleJTSwitchCase(CaseRec& CR,
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CaseRecVector& WorkList,
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Value* SV,
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MachineBasicBlock* Default) {
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// Get the MachineFunction which holds the current MBB. This is used when
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// inserting any additional MBBs necessary to represent the switch.
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MachineFunction *CurMF = CurMBB->getParent();
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// Figure out which block is immediately after the current one.
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MachineBasicBlock *NextBlock = 0;
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MachineFunction::iterator BBI = CR.CaseBB;
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if (++BBI != CurMBB->getParent()->end())
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NextBlock = BBI;
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Case& FrontCase = *CR.Range.first;
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Case& BackCase = *(CR.Range.second-1);
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const BasicBlock *LLVMBB = CR.CaseBB->getBasicBlock();
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uint64_t First = cast<ConstantInt>(FrontCase.first)->getSExtValue();
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uint64_t Last = cast<ConstantInt>(BackCase.first)->getSExtValue();
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// Create a new basic block to hold the code for loading the address
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// of the jump table, and jumping to it. Update successor information;
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// we will either branch to the default case for the switch, or the jump
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// table.
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MachineBasicBlock *JumpTableBB = new MachineBasicBlock(LLVMBB);
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CurMF->getBasicBlockList().insert(BBI, JumpTableBB);
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CR.CaseBB->addSuccessor(Default);
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CR.CaseBB->addSuccessor(JumpTableBB);
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// Build a vector of destination BBs, corresponding to each target
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// of the jump table. If the value of the jump table slot corresponds to
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// a case statement, push the case's BB onto the vector, otherwise, push
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// the default BB.
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std::vector<MachineBasicBlock*> DestBBs;
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int64_t TEI = First;
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for (CaseItr I = CR.Range.first, E = CR.Range.second; I != E; ++TEI)
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if (cast<ConstantInt>(I->first)->getSExtValue() == TEI) {
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DestBBs.push_back(I->second);
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++I;
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} else {
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DestBBs.push_back(Default);
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}
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// Update successor info. Add one edge to each unique successor.
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// Vector bool would be better, but vector<bool> is really slow.
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std::vector<unsigned char> SuccsHandled;
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SuccsHandled.resize(CR.CaseBB->getParent()->getNumBlockIDs());
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for (std::vector<MachineBasicBlock*>::iterator I = DestBBs.begin(),
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E = DestBBs.end(); I != E; ++I) {
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if (!SuccsHandled[(*I)->getNumber()]) {
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SuccsHandled[(*I)->getNumber()] = true;
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JumpTableBB->addSuccessor(*I);
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}
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}
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// Create a jump table index for this jump table, or return an existing
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// one.
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unsigned JTI = CurMF->getJumpTableInfo()->getJumpTableIndex(DestBBs);
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// Set the jump table information so that we can codegen it as a second
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// MachineBasicBlock
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SelectionDAGISel::JumpTable JT(-1UL, JTI, JumpTableBB, Default);
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SelectionDAGISel::JumpTableHeader JTH(First, Last, SV, CR.CaseBB,
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(CR.CaseBB == CurMBB));
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if (CR.CaseBB == CurMBB)
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visitJumpTableHeader(JT, JTH);
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JTCases.push_back(SelectionDAGISel::JumpTableBlock(JTH, JT));
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}
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/// handleBTSmallSwitchCase - handle leaf in the binary comparison tree. Just
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/// emit test.
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void SelectionDAGLowering::handleBTSmallSwitchCase(CaseRec& CR,
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CaseRecVector& WorkList,
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Value* SV,
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MachineBasicBlock* Default) {
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Case& FrontCase = *CR.Range.first;
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// Create a CaseBlock record representing a conditional branch to
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// the Case's target mbb if the value being switched on SV is equal
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// to C. Otherwise, branch to default.
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Constant *C = FrontCase.first;
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MachineBasicBlock *Target = FrontCase.second;
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SelectionDAGISel::CaseBlock CB(ISD::SETEQ, SV, C, Target, Default,
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CR.CaseBB);
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// If the MBB representing the leaf node is the current MBB, then just
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// call visitSwitchCase to emit the code into the current block.
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// Otherwise, push the CaseBlock onto the vector to be later processed
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// by SDISel, and insert the node's MBB before the next MBB.
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if (CR.CaseBB == CurMBB)
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visitSwitchCase(CB);
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else
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SwitchCases.push_back(CB);
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}
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/// handleBTSplitSwitchCase - emit comparison and split binary search tree into
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/// 2 subtrees.
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void SelectionDAGLowering::handleBTSplitSwitchCase(CaseRec& CR,
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CaseRecVector& WorkList,
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Value* SV,
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MachineBasicBlock* Default) {
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// Get the MachineFunction which holds the current MBB. This is used when
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// inserting any additional MBBs necessary to represent the switch.
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MachineFunction *CurMF = CurMBB->getParent();
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// Figure out which block is immediately after the current one.
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MachineBasicBlock *NextBlock = 0;
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MachineFunction::iterator BBI = CR.CaseBB;
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if (++BBI != CurMBB->getParent()->end())
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NextBlock = BBI;
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Case& FrontCase = *CR.Range.first;
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Case& BackCase = *(CR.Range.second-1);
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const BasicBlock *LLVMBB = CR.CaseBB->getBasicBlock();
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// Size is the number of Cases represented by this range.
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unsigned Size = CR.Range.second - CR.Range.first;
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uint64_t First = cast<ConstantInt>(FrontCase.first)->getSExtValue();
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uint64_t Last = cast<ConstantInt>(BackCase.first)->getSExtValue();
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double Density = 0;
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CaseItr Pivot;
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// Select optimal pivot, maximizing sum density of LHS and RHS. This will
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// (heuristically) allow us to emit JumpTable's later.
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unsigned LSize = 1;
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unsigned RSize = Size-1;
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for (CaseItr I = CR.Range.first, J=I+1, E = CR.Range.second;
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J!=E; ++I, ++J, ++LSize, --RSize) {
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uint64_t LEnd = cast<ConstantInt>(I->first)->getSExtValue();
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uint64_t RBegin = cast<ConstantInt>(J->first)->getSExtValue();
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double LDensity = (double)LSize / (double)((LEnd - First) + 1ULL);
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double RDensity = (double)RSize / (double)((Last - RBegin) + 1ULL);
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if (Density < (LDensity + RDensity)) {
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Pivot = J;
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Density = LDensity + RDensity;
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}
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}
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CaseRange LHSR(CR.Range.first, Pivot);
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CaseRange RHSR(Pivot, CR.Range.second);
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Constant *C = Pivot->first;
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MachineBasicBlock *FalseBB = 0, *TrueBB = 0;
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// We know that we branch to the LHS if the Value being switched on is
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// less than the Pivot value, C. We use this to optimize our binary
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// tree a bit, by recognizing that if SV is greater than or equal to the
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// LHS's Case Value, and that Case Value is exactly one less than the
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// Pivot's Value, then we can branch directly to the LHS's Target,
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// rather than creating a leaf node for it.
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if ((LHSR.second - LHSR.first) == 1 &&
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LHSR.first->first == CR.GE &&
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cast<ConstantInt>(C)->getZExtValue() ==
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(cast<ConstantInt>(CR.GE)->getZExtValue() + 1ULL)) {
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TrueBB = LHSR.first->second;
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} else {
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TrueBB = new MachineBasicBlock(LLVMBB);
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CurMF->getBasicBlockList().insert(BBI, TrueBB);
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WorkList.push_back(CaseRec(TrueBB, C, CR.GE, LHSR));
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}
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// Similar to the optimization above, if the Value being switched on is
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// known to be less than the Constant CR.LT, and the current Case Value
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// is CR.LT - 1, then we can branch directly to the target block for
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// the current Case Value, rather than emitting a RHS leaf node for it.
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if ((RHSR.second - RHSR.first) == 1 && CR.LT &&
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cast<ConstantInt>(RHSR.first->first)->getZExtValue() ==
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(cast<ConstantInt>(CR.LT)->getZExtValue() - 1ULL)) {
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FalseBB = RHSR.first->second;
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} else {
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FalseBB = new MachineBasicBlock(LLVMBB);
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CurMF->getBasicBlockList().insert(BBI, FalseBB);
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WorkList.push_back(CaseRec(FalseBB,CR.LT,C,RHSR));
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}
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// Create a CaseBlock record representing a conditional branch to
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// the LHS node if the value being switched on SV is less than C.
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// Otherwise, branch to LHS.
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SelectionDAGISel::CaseBlock CB(ISD::SETLT, SV, C, TrueBB, FalseBB,
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CR.CaseBB);
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if (CR.CaseBB == CurMBB)
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visitSwitchCase(CB);
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else
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SwitchCases.push_back(CB);
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}
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void SelectionDAGLowering::visitSwitch(SwitchInst &I) {
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// Figure out which block is immediately after the current one.
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MachineBasicBlock *NextBlock = 0;
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@ -1245,13 +1522,8 @@ void SelectionDAGLowering::visitSwitch(SwitchInst &I) {
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// search tree.
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Value *SV = I.getOperand(0);
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// Get the MachineFunction which holds the current MBB. This is used during
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// emission of jump tables, and when inserting any additional MBBs necessary
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// to represent the switch.
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MachineFunction *CurMF = CurMBB->getParent();
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// Push the initial CaseRec onto the worklist
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std::vector<CaseRec> WorkList;
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CaseRecVector WorkList;
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WorkList.push_back(CaseRec(CurMBB,0,0,CaseRange(Cases.begin(),Cases.end())));
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while (!WorkList.empty()) {
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@ -1260,7 +1532,6 @@ void SelectionDAGLowering::visitSwitch(SwitchInst &I) {
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WorkList.pop_back();
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Case& FrontCase = *CR.Range.first;
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Case& BackCase = *(CR.Range.second-1);
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const BasicBlock *LLVMBB = CR.CaseBB->getBasicBlock();
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// Figure out which block is immediately after the current one.
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NextBlock = 0;
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@ -1275,52 +1546,7 @@ void SelectionDAGLowering::visitSwitch(SwitchInst &I) {
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// If the range has few cases (two or less) emit a series of specific
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// tests.
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if (Size < 3) {
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// TODO: If any two of the cases has the same destination, and if one value
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// is the same as the other, but has one bit unset that the other has set,
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// use bit manipulation to do two compares at once. For example:
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// "if (X == 6 || X == 4)" -> "if ((X|2) == 6)"
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// Rearrange the case blocks so that the last one falls through if possible.
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if (NextBlock && Default != NextBlock && BackCase.second != NextBlock) {
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// The last case block won't fall through into 'NextBlock' if we emit the
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// branches in this order. See if rearranging a case value would help.
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for (CaseItr I = CR.Range.first, E = CR.Range.second-1; I != E; ++I) {
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if (I->second == NextBlock) {
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std::swap(*I, BackCase);
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break;
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}
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}
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}
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// Create a CaseBlock record representing a conditional branch to
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// the Case's target mbb if the value being switched on SV is equal
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// to C.
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MachineBasicBlock *CurBlock = CR.CaseBB;
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for (CaseItr I = CR.Range.first, E = CR.Range.second; I != E; ++I) {
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MachineBasicBlock *FallThrough;
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if (I != E-1) {
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FallThrough = new MachineBasicBlock(CurBlock->getBasicBlock());
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CurMF->getBasicBlockList().insert(BBI, FallThrough);
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} else {
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// If the last case doesn't match, go to the default block.
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FallThrough = Default;
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}
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SelectionDAGISel::CaseBlock CB(ISD::SETEQ, SV, I->first,
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I->second, FallThrough, CurBlock);
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// If emitting the first comparison, just call visitSwitchCase to emit the
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// code into the current block. Otherwise, push the CaseBlock onto the
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// vector to be later processed by SDISel, and insert the node's MBB
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// before the next MBB.
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if (CurBlock == CurMBB)
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visitSwitchCase(CB);
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else
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SwitchCases.push_back(CB);
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CurBlock = FallThrough;
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}
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handleSmallSwitchRange(CR, WorkList, SV, Default);
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continue;
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}
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@ -1336,56 +1562,7 @@ void SelectionDAGLowering::visitSwitch(SwitchInst &I) {
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double Density = (double)Size / (double)((Last - First) + 1ULL);
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if (Density >= 0.3125) {
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// Create a new basic block to hold the code for loading the address
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// of the jump table, and jumping to it. Update successor information;
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// we will either branch to the default case for the switch, or the jump
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// table.
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MachineBasicBlock *JumpTableBB = new MachineBasicBlock(LLVMBB);
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CurMF->getBasicBlockList().insert(BBI, JumpTableBB);
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CR.CaseBB->addSuccessor(Default);
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CR.CaseBB->addSuccessor(JumpTableBB);
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// Build a vector of destination BBs, corresponding to each target
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// of the jump table. If the value of the jump table slot corresponds to
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// a case statement, push the case's BB onto the vector, otherwise, push
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// the default BB.
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std::vector<MachineBasicBlock*> DestBBs;
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int64_t TEI = First;
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for (CaseItr I = CR.Range.first, E = CR.Range.second; I != E; ++TEI)
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if (cast<ConstantInt>(I->first)->getSExtValue() == TEI) {
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DestBBs.push_back(I->second);
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++I;
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} else {
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DestBBs.push_back(Default);
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}
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// Update successor info. Add one edge to each unique successor.
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// Vector bool would be better, but vector<bool> is really slow.
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std::vector<unsigned char> SuccsHandled;
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SuccsHandled.resize(CR.CaseBB->getParent()->getNumBlockIDs());
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for (std::vector<MachineBasicBlock*>::iterator I = DestBBs.begin(),
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E = DestBBs.end(); I != E; ++I) {
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if (!SuccsHandled[(*I)->getNumber()]) {
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SuccsHandled[(*I)->getNumber()] = true;
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JumpTableBB->addSuccessor(*I);
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}
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}
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// Create a jump table index for this jump table, or return an existing
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// one.
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||||
unsigned JTI = CurMF->getJumpTableInfo()->getJumpTableIndex(DestBBs);
|
||||
|
||||
// Set the jump table information so that we can codegen it as a second
|
||||
// MachineBasicBlock
|
||||
SelectionDAGISel::JumpTable JT(-1UL, JTI, JumpTableBB, Default);
|
||||
SelectionDAGISel::JumpTableHeader JTH(First, Last, SV, CR.CaseBB,
|
||||
(CR.CaseBB == CurMBB));
|
||||
if (CR.CaseBB == CurMBB)
|
||||
visitJumpTableHeader(JT, JTH);
|
||||
|
||||
JTCases.push_back(SelectionDAGISel::JumpTableBlock(JTH, JT));
|
||||
|
||||
handleJTSwitchCase(CR, WorkList, SV, Default);
|
||||
continue;
|
||||
}
|
||||
}
|
||||
@ -1393,93 +1570,11 @@ void SelectionDAGLowering::visitSwitch(SwitchInst &I) {
|
||||
// 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) {
|
||||
// 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);
|
||||
} else {
|
||||
uint64_t First = cast<ConstantInt>(FrontCase.first)->getSExtValue();
|
||||
uint64_t Last = cast<ConstantInt>(BackCase.first)->getSExtValue();
|
||||
double Density = 0;
|
||||
CaseItr Pivot;
|
||||
|
||||
// Select optimal pivot, maximizing sum density of LHS and RHS. This will
|
||||
// (heuristically) allow us to emit JumpTable's later.
|
||||
unsigned LSize = 1;
|
||||
unsigned RSize = Size-1;
|
||||
for (CaseItr I = CR.Range.first, J=I+1, E = CR.Range.second;
|
||||
J!=E; ++I, ++J, ++LSize, --RSize) {
|
||||
uint64_t LEnd = cast<ConstantInt>(I->first)->getSExtValue();
|
||||
uint64_t RBegin = cast<ConstantInt>(J->first)->getSExtValue();
|
||||
double LDensity = (double)LSize / (double)((LEnd - First) + 1ULL);
|
||||
double RDensity = (double)RSize / (double)((Last - RBegin) + 1ULL);
|
||||
if (Density < (LDensity + RDensity)) {
|
||||
Pivot = J;
|
||||
Density = LDensity + RDensity;
|
||||
}
|
||||
}
|
||||
|
||||
CaseRange LHSR(CR.Range.first, Pivot);
|
||||
CaseRange RHSR(Pivot, CR.Range.second);
|
||||
Constant *C = Pivot->first;
|
||||
MachineBasicBlock *FalseBB = 0, *TrueBB = 0;
|
||||
|
||||
// We know that we branch to the LHS if the Value being switched on is
|
||||
// less than the Pivot value, C. We use this to optimize our binary
|
||||
// tree a bit, by recognizing that if SV is greater than or equal to the
|
||||
// LHS's Case Value, and that Case Value is exactly one less than the
|
||||
// Pivot's Value, then we can branch directly to the LHS's Target,
|
||||
// rather than creating a leaf node for it.
|
||||
if ((LHSR.second - LHSR.first) == 1 &&
|
||||
LHSR.first->first == CR.GE &&
|
||||
cast<ConstantInt>(C)->getZExtValue() ==
|
||||
(cast<ConstantInt>(CR.GE)->getZExtValue() + 1ULL)) {
|
||||
TrueBB = LHSR.first->second;
|
||||
} else {
|
||||
TrueBB = new MachineBasicBlock(LLVMBB);
|
||||
CurMF->getBasicBlockList().insert(BBI, TrueBB);
|
||||
WorkList.push_back(CaseRec(TrueBB, C, CR.GE, LHSR));
|
||||
}
|
||||
|
||||
// Similar to the optimization above, if the Value being switched on is
|
||||
// known to be less than the Constant CR.LT, and the current Case Value
|
||||
// is CR.LT - 1, then we can branch directly to the target block for
|
||||
// the current Case Value, rather than emitting a RHS leaf node for it.
|
||||
if ((RHSR.second - RHSR.first) == 1 && CR.LT &&
|
||||
cast<ConstantInt>(RHSR.first->first)->getZExtValue() ==
|
||||
(cast<ConstantInt>(CR.LT)->getZExtValue() - 1ULL)) {
|
||||
FalseBB = RHSR.first->second;
|
||||
} else {
|
||||
FalseBB = new MachineBasicBlock(LLVMBB);
|
||||
CurMF->getBasicBlockList().insert(BBI, FalseBB);
|
||||
WorkList.push_back(CaseRec(FalseBB,CR.LT,C,RHSR));
|
||||
}
|
||||
|
||||
// Create a CaseBlock record representing a conditional branch to
|
||||
// the LHS node if the value being switched on SV is less than C.
|
||||
// Otherwise, branch to LHS.
|
||||
SelectionDAGISel::CaseBlock CB(ISD::SETLT, SV, C, TrueBB, FalseBB,
|
||||
CR.CaseBB);
|
||||
|
||||
if (CR.CaseBB == CurMBB)
|
||||
visitSwitchCase(CB);
|
||||
else
|
||||
SwitchCases.push_back(CB);
|
||||
}
|
||||
if (Size == 1)
|
||||
handleBTSmallSwitchCase(CR, WorkList, SV, Default);
|
||||
else
|
||||
handleBTSplitSwitchCase(CR, WorkList, SV, Default);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user