Fix the updating of the machine CFG when a PHI node was in a successor of

the jump table's range check block.  This re-enables 100% dense jump tables
by default on PPC & x86


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27952 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nate Begeman 2006-04-23 06:26:20 +00:00
parent 84bfed087b
commit 9453eea49b
2 changed files with 16 additions and 8 deletions

View File

@ -41,7 +41,7 @@ public:
SelectionDAG *CurDAG;
MachineBasicBlock *BB;
SelectionDAGISel(TargetLowering &tli) : TLI(tli), JT(0,0,0) {}
SelectionDAGISel(TargetLowering &tli) : TLI(tli), JT(0,0,0,0) {}
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
@ -89,8 +89,8 @@ public:
MachineBasicBlock *ThisBB;
};
struct JumpTable {
JumpTable(unsigned R, unsigned J, MachineBasicBlock *me) : Reg(R), JTI(J),
MBB(me) {}
JumpTable(unsigned R, unsigned J, MachineBasicBlock *M,
MachineBasicBlock *D) : Reg(R), JTI(J), MBB(M), Default(D) {}
// Reg - the virtual register containing the index of the jump table entry
// to jump to.
unsigned Reg;
@ -98,6 +98,9 @@ public:
unsigned JTI;
// MBB - the MBB into which to emit the code for the indirect jump.
MachineBasicBlock *MBB;
// Default - the MBB of the default bb, which is a successor of the range
// check MBB. This is when updating PHI nodes in successors.
MachineBasicBlock *Default;
// SuccMBBs - a vector of unique successor MBBs used for updating CFG info
// and PHI nodes.
std::set<MachineBasicBlock*> SuccMBBs;

View File

@ -408,7 +408,7 @@ public:
SelectionDAGLowering(SelectionDAG &dag, TargetLowering &tli,
FunctionLoweringInfo &funcinfo)
: TLI(tli), DAG(dag), TD(DAG.getTarget().getTargetData()),
JT(0,0,0), FuncInfo(funcinfo) {
JT(0,0,0,0), FuncInfo(funcinfo) {
}
/// getRoot - Return the current virtual root of the Selection DAG.
@ -891,7 +891,7 @@ void SelectionDAGLowering::visitSwitch(SwitchInst &I) {
// FIXME: Make this work with 64 bit targets someday, possibly by always
// doing differences there so that entries stay 32 bits.
// FIXME: Make this work with PIC code
if (0 && TLI.isOperationLegal(ISD::BRIND, TLI.getPointerTy()) &&
if (TLI.isOperationLegal(ISD::BRIND, TLI.getPointerTy()) &&
TLI.getPointerTy() == MVT::i32 &&
(Relocs == Reloc::Static || Relocs == Reloc::DynamicNoPIC) &&
Cases.size() > 3) {
@ -955,6 +955,7 @@ void SelectionDAGLowering::visitSwitch(SwitchInst &I) {
JT.Reg = JumpTableReg;
JT.JTI = JTI;
JT.MBB = JumpTableBB;
JT.Default = Default;
JT.SuccMBBs = UniqueBBs;
return;
}
@ -3190,12 +3191,15 @@ void SelectionDAGISel::SelectBasicBlock(BasicBlock *LLVMBB, MachineFunction &MF,
return;
}
// If we need to emit a jump table,
// If the JumpTable record is filled in, then we need to emit a jump table.
// Updating the PHI nodes is tricky in this case, since we need to determine
// whether the PHI is a successor of the range check MBB or the jump table MBB
if (JT.Reg) {
assert(SwitchCases.empty() && "Cannot have jump table and lowered switch");
SelectionDAG SDAG(TLI, MF, getAnalysisToUpdate<MachineDebugInfo>());
CurDAG = &SDAG;
SelectionDAGLowering SDL(SDAG, TLI, FuncInfo);
MachineBasicBlock *RangeBB = BB;
// Set the current basic block to the mbb we wish to insert the code into
BB = JT.MBB;
SDL.setCurrentBasicBlock(BB);
@ -3209,9 +3213,10 @@ void SelectionDAGISel::SelectBasicBlock(BasicBlock *LLVMBB, MachineFunction &MF,
MachineBasicBlock *PHIBB = PHI->getParent();
assert(PHI->getOpcode() == TargetInstrInfo::PHI &&
"This is not a machine PHI node that we are updating!");
if (JT.SuccMBBs.find(PHIBB) != JT.SuccMBBs.end()) {
if (PHIBB == JT.Default || JT.SuccMBBs.find(PHIBB) != JT.SuccMBBs.end()) {
PHIBB = (PHIBB == JT.Default) ? RangeBB : BB;
PHI->addRegOperand(PHINodesToUpdate[pi].second);
PHI->addMachineBasicBlockOperand(BB);
PHI->addMachineBasicBlockOperand(PHIBB);
}
}
return;