cerr << "\n";
}
private:
+ /// isStackEmpty - Return true if the FP stack is empty.
+ bool isStackEmpty() const {
+ return StackTop == 0;
+ }
+
// getSlot - Return the stack slot number a particular register number is
- // in...
+ // in.
unsigned getSlot(unsigned RegNo) const {
assert(RegNo < 8 && "Regno out of range!");
return RegMap[RegNo];
}
- // getStackEntry - Return the X86::FP<n> register in register ST(i)
+ // getStackEntry - Return the X86::FP<n> register in register ST(i).
unsigned getStackEntry(unsigned STi) const {
assert(STi < StackTop && "Access past stack top!");
return Stack[StackTop-1-STi];
}
// getSTReg - Return the X86::ST(i) register which contains the specified
- // FP<RegNo> register
+ // FP<RegNo> register.
unsigned getSTReg(unsigned RegNo) const {
return StackTop - 1 - getSlot(RegNo) + llvm::X86::ST0;
}
- // pushReg - Push the specified FP<n> register onto the stack
+ // pushReg - Push the specified FP<n> register onto the stack.
void pushReg(unsigned Reg) {
assert(Reg < 8 && "Register number out of range!");
assert(StackTop < 8 && "Stack overflow!");
}
bool isAtTop(unsigned RegNo) const { return getSlot(RegNo) == StackTop-1; }
- void moveToTop(unsigned RegNo, MachineBasicBlock::iterator &I) {
- if (!isAtTop(RegNo)) {
- unsigned STReg = getSTReg(RegNo);
- unsigned RegOnTop = getStackEntry(0);
+ void moveToTop(unsigned RegNo, MachineBasicBlock::iterator I) {
+ if (isAtTop(RegNo)) return;
+
+ unsigned STReg = getSTReg(RegNo);
+ unsigned RegOnTop = getStackEntry(0);
- // Swap the slots the regs are in
- std::swap(RegMap[RegNo], RegMap[RegOnTop]);
+ // Swap the slots the regs are in.
+ std::swap(RegMap[RegNo], RegMap[RegOnTop]);
- // Swap stack slot contents
- assert(RegMap[RegOnTop] < StackTop);
- std::swap(Stack[RegMap[RegOnTop]], Stack[StackTop-1]);
+ // Swap stack slot contents.
+ assert(RegMap[RegOnTop] < StackTop);
+ std::swap(Stack[RegMap[RegOnTop]], Stack[StackTop-1]);
- // Emit an fxch to update the runtime processors version of the state
- BuildMI(*MBB, I, TII->get(X86::XCH_F)).addReg(STReg);
- NumFXCH++;
- }
+ // Emit an fxch to update the runtime processors version of the state.
+ BuildMI(*MBB, I, TII->get(X86::XCH_F)).addReg(STReg);
+ NumFXCH++;
}
void duplicateToTop(unsigned RegNo, unsigned AsReg, MachineInstr *I) {
for (MachineBasicBlock::iterator I = BB.begin(); I != BB.end(); ++I) {
MachineInstr *MI = I;
unsigned Flags = MI->getDesc().TSFlags;
- if ((Flags & X86II::FPTypeMask) == X86II::NotFP)
+
+ unsigned FPInstClass = Flags & X86II::FPTypeMask;
+ if (MI->getOpcode() == TargetInstrInfo::INLINEASM)
+ FPInstClass = X86II::SpecialFP;
+
+ if (FPInstClass == X86II::NotFP)
continue; // Efficiently ignore non-fp insts!
MachineInstr *PrevMI = 0;
DeadRegs.push_back(MO.getReg());
}
- switch (Flags & X86II::FPTypeMask) {
+ switch (FPInstClass) {
case X86II::ZeroArgFP: handleZeroArgFP(I); break;
case X86II::OneArgFP: handleOneArgFP(I); break; // fstp ST(0)
case X86II::OneArgFPRW: handleOneArgFPRW(I); break; // ST(0) = fsqrt(ST(0))
Changed = true;
}
- assert(StackTop == 0 && "Stack not empty at end of basic block?");
+ assert(isStackEmpty() && "Stack not empty at end of basic block?");
return Changed;
}
pushReg(getFPReg(MI->getOperand(0)));
pushReg(getFPReg(MI->getOperand(1)));
break;
- case X86::FpSETRESULT32:
- case X86::FpSETRESULT64:
- case X86::FpSETRESULT80:
+ case X86::FpSET_ST0_32:
+ case X86::FpSET_ST0_64:
+ case X86::FpSET_ST0_80:
assert(StackTop == 1 && "Stack should have one element on it to return!");
--StackTop; // "Forget" we have something on the top of stack!
break;
// This could be made better, but would require substantial changes.
duplicateToTop(SrcReg, DestReg, I);
}
+ }
break;
+ case TargetInstrInfo::INLINEASM: {
+ // The inline asm MachineInstr currently only *uses* FP registers for the
+ // 'f' constraint. These should be turned into the current ST(x) register
+ // in the machine instr. Also, any kills should be explicitly popped after
+ // the inline asm.
+ unsigned Kills[7];
+ unsigned NumKills = 0;
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ MachineOperand &Op = MI->getOperand(i);
+ if (!Op.isReg() || Op.getReg() < X86::FP0 || Op.getReg() > X86::FP6)
+ continue;
+ assert(Op.isUse() && "Only handle inline asm uses right now");
+
+ unsigned FPReg = getFPReg(Op);
+ Op.setReg(getSTReg(FPReg));
+
+ // If we kill this operand, make sure to pop it from the stack after the
+ // asm. We just remember it for now, and pop them all off at the end in
+ // a batch.
+ if (Op.isKill())
+ Kills[NumKills++] = FPReg;
+ }
+
+ // If this asm kills any FP registers (is the last use of them) we must
+ // explicitly emit pop instructions for them. Do this now after the asm has
+ // executed so that the ST(x) numbers are not off (which would happen if we
+ // did this inline with operand rewriting).
+ //
+ // Note: this might be a non-optimal pop sequence. We might be able to do
+ // better by trying to pop in stack order or something.
+ MachineBasicBlock::iterator InsertPt = MI;
+ while (NumKills)
+ freeStackSlotAfter(InsertPt, Kills[--NumKills]);
+
+ // Don't delete the inline asm!
+ return;
}
+
+ case X86::RET:
+ case X86::RETI:
+ // If RET has an FP register use operand, pass the first one in ST(0) and
+ // the second one in ST(1).
+ if (isStackEmpty()) return; // Quick check to see if any are possible.
+
+ // Find the register operands.
+ unsigned FirstFPRegOp = ~0U, SecondFPRegOp = ~0U;
+
+ for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
+ MachineOperand &Op = MI->getOperand(i);
+ if (!Op.isReg() || Op.getReg() < X86::FP0 || Op.getReg() > X86::FP6)
+ continue;
+ assert(Op.isUse() && Op.isKill() &&
+ "Ret only defs operands, and values aren't live beyond it");
+
+ if (FirstFPRegOp == ~0U)
+ FirstFPRegOp = getFPReg(Op);
+ else {
+ assert(SecondFPRegOp == ~0U && "More than two fp operands!");
+ SecondFPRegOp = getFPReg(Op);
+ }
+
+ // Remove the operand so that later passes don't see it.
+ MI->RemoveOperand(i);
+ --i, --e;
+ }
+
+ // There are only four possibilities here:
+ // 1) we are returning a single FP value. In this case, it has to be in
+ // ST(0) already, so just declare success by removing the value from the
+ // FP Stack.
+ if (SecondFPRegOp == ~0U) {
+ // Assert that the top of stack contains the right FP register.
+ assert(StackTop == 1 && FirstFPRegOp == getStackEntry(0) &&
+ "Top of stack not the right register for RET!");
+
+ // Ok, everything is good, mark the value as not being on the stack
+ // anymore so that our assertion about the stack being empty at end of
+ // block doesn't fire.
+ StackTop = 0;
+ return;
+ }
+
+ assert(0 && "TODO: This code should work, but has never been tested."
+ "Test it when we have multiple FP return values working");
+
+ // Otherwise, we are returning two values:
+ // 2) If returning the same value for both, we only have one thing in the FP
+ // stack. Consider: RET FP1, FP1
+ if (StackTop == 1) {
+ assert(FirstFPRegOp == SecondFPRegOp && FirstFPRegOp == getStackEntry(0)&&
+ "Stack misconfiguration for RET!");
+
+ // Duplicate the TOS so that we return it twice. Just pick some other FPx
+ // register to hold it.
+ unsigned NewReg = (FirstFPRegOp+1)%7;
+ duplicateToTop(FirstFPRegOp, NewReg, MI);
+ FirstFPRegOp = NewReg;
+ }
+
+ /// Okay we know we have two different FPx operands now:
+ assert(StackTop == 2 && "Must have two values live!");
+
+ /// 3) If SecondFPRegOp is currently in ST(0) and FirstFPRegOp is currently
+ /// in ST(1). In this case, emit an fxch.
+ if (getStackEntry(0) == SecondFPRegOp) {
+ assert(getStackEntry(1) == FirstFPRegOp && "Unknown regs live");
+ moveToTop(FirstFPRegOp, MI);
+ }
+
+ /// 4) Finally, FirstFPRegOp must be in ST(0) and SecondFPRegOp must be in
+ /// ST(1). Just remove both from our understanding of the stack and return.
+ assert(getStackEntry(0) == FirstFPRegOp && "Unknown regs live");
+ assert(getStackEntry(0) == SecondFPRegOp && "Unknown regs live");
+ StackTop = 0;
+ return;
}
I = MBB->erase(I); // Remove the pseudo instruction
projects / oota-llvm.git / blobdiff