diff options
Diffstat (limited to 'contrib/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp')
| -rw-r--r-- | contrib/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp | 186 |
1 files changed, 103 insertions, 83 deletions
diff --git a/contrib/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/contrib/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp index f0f4743298e7..2ff66f8f8715 100644 --- a/contrib/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp +++ b/contrib/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp @@ -30,6 +30,12 @@ #include "llvm/Support/MathExtras.h" using namespace llvm; +/// MinRCSize - Smallest register class we allow when constraining virtual +/// registers. If satisfying all register class constraints would require +/// using a smaller register class, emit a COPY to a new virtual register +/// instead. +const unsigned MinRCSize = 4; + /// CountResults - The results of target nodes have register or immediate /// operands first, then an optional chain, and optional glue operands (which do /// not go into the resulting MachineInstr). @@ -87,7 +93,7 @@ EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned, UI != E; ++UI) { SDNode *User = *UI; bool Match = true; - if (User->getOpcode() == ISD::CopyToReg && + if (User->getOpcode() == ISD::CopyToReg && User->getOperand(2).getNode() == Node && User->getOperand(2).getResNo() == ResNo) { unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); @@ -113,7 +119,8 @@ EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned, if (!UseRC) UseRC = RC; else if (RC) { - const TargetRegisterClass *ComRC = getCommonSubClass(UseRC, RC); + const TargetRegisterClass *ComRC = + TRI->getCommonSubClass(UseRC, RC); // If multiple uses expect disjoint register classes, we emit // copies in AddRegisterOperand. if (ComRC) @@ -139,7 +146,7 @@ EmitCopyFromReg(SDNode *Node, unsigned ResNo, bool IsClone, bool IsCloned, } else { DstRC = TLI->getRegClassFor(VT); } - + // If all uses are reading from the src physical register and copying the // register is either impossible or very expensive, then don't create a copy. if (MatchReg && SrcRC->getCopyCost() < 0) { @@ -167,7 +174,7 @@ unsigned InstrEmitter::getDstOfOnlyCopyToRegUse(SDNode *Node, return 0; SDNode *User = *Node->use_begin(); - if (User->getOpcode() == ISD::CopyToReg && + if (User->getOpcode() == ISD::CopyToReg && User->getOperand(2).getNode() == Node && User->getOperand(2).getResNo() == ResNo) { unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); @@ -202,7 +209,7 @@ void InstrEmitter::CreateVirtualRegisters(SDNode *Node, MachineInstr *MI, for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end(); UI != E; ++UI) { SDNode *User = *UI; - if (User->getOpcode() == ISD::CopyToReg && + if (User->getOpcode() == ISD::CopyToReg && User->getOperand(2).getNode() == Node && User->getOperand(2).getResNo() == i) { unsigned Reg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); @@ -280,15 +287,16 @@ InstrEmitter::AddRegisterOperand(MachineInstr *MI, SDValue Op, MCID.OpInfo[IIOpNum].isOptionalDef(); // If the instruction requires a register in a different class, create - // a new virtual register and copy the value into it. + // a new virtual register and copy the value into it, but first attempt to + // shrink VReg's register class within reason. For example, if VReg == GR32 + // and II requires a GR32_NOSP, just constrain VReg to GR32_NOSP. if (II) { - const TargetRegisterClass *SrcRC = MRI->getRegClass(VReg); const TargetRegisterClass *DstRC = 0; if (IIOpNum < II->getNumOperands()) DstRC = TII->getRegClass(*II, IIOpNum, TRI); assert((DstRC || (MCID.isVariadic() && IIOpNum >= MCID.getNumOperands())) && "Don't have operand info for this instruction!"); - if (DstRC && !SrcRC->hasSuperClassEq(DstRC)) { + if (DstRC && !MRI->constrainRegClass(VReg, DstRC, MinRCSize)) { unsigned NewVReg = MRI->createVirtualRegister(DstRC); BuildMI(*MBB, InsertPos, Op.getNode()->getDebugLoc(), TII->get(TargetOpcode::COPY), NewVReg).addReg(VReg); @@ -326,7 +334,7 @@ InstrEmitter::AddRegisterOperand(MachineInstr *MI, SDValue Op, /// AddOperand - Add the specified operand to the specified machine instr. II /// specifies the instruction information for the node, and IIOpNum is the -/// operand number (in the II) that we are adding. IIOpNum and II are used for +/// operand number (in the II) that we are adding. IIOpNum and II are used for /// assertions only. void InstrEmitter::AddOperand(MachineInstr *MI, SDValue Op, unsigned IIOpNum, @@ -356,7 +364,7 @@ void InstrEmitter::AddOperand(MachineInstr *MI, SDValue Op, } else if (ConstantPoolSDNode *CP = dyn_cast<ConstantPoolSDNode>(Op)) { int Offset = CP->getOffset(); unsigned Align = CP->getAlignment(); - const Type *Type = CP->getType(); + Type *Type = CP->getType(); // MachineConstantPool wants an explicit alignment. if (Align == 0) { Align = TM->getTargetData()->getPrefTypeAlignment(Type); @@ -365,7 +373,7 @@ void InstrEmitter::AddOperand(MachineInstr *MI, SDValue Op, Align = TM->getTargetData()->getTypeAllocSize(Type); } } - + unsigned Idx; MachineConstantPool *MCP = MF->getConstantPool(); if (CP->isMachineConstantPoolEntry()) @@ -389,35 +397,44 @@ void InstrEmitter::AddOperand(MachineInstr *MI, SDValue Op, } } -/// getSuperRegisterRegClass - Returns the register class of a superreg A whose -/// "SubIdx"'th sub-register class is the specified register class and whose -/// type matches the specified type. -static const TargetRegisterClass* -getSuperRegisterRegClass(const TargetRegisterClass *TRC, - unsigned SubIdx, EVT VT) { - // Pick the register class of the superegister for this type - for (TargetRegisterInfo::regclass_iterator I = TRC->superregclasses_begin(), - E = TRC->superregclasses_end(); I != E; ++I) - if ((*I)->hasType(VT) && (*I)->getSubRegisterRegClass(SubIdx) == TRC) - return *I; - assert(false && "Couldn't find the register class"); - return 0; +unsigned InstrEmitter::ConstrainForSubReg(unsigned VReg, unsigned SubIdx, + EVT VT, DebugLoc DL) { + const TargetRegisterClass *VRC = MRI->getRegClass(VReg); + const TargetRegisterClass *RC = TRI->getSubClassWithSubReg(VRC, SubIdx); + + // RC is a sub-class of VRC that supports SubIdx. Try to constrain VReg + // within reason. + if (RC && RC != VRC) + RC = MRI->constrainRegClass(VReg, RC, MinRCSize); + + // VReg has been adjusted. It can be used with SubIdx operands now. + if (RC) + return VReg; + + // VReg couldn't be reasonably constrained. Emit a COPY to a new virtual + // register instead. + RC = TRI->getSubClassWithSubReg(TLI->getRegClassFor(VT), SubIdx); + assert(RC && "No legal register class for VT supports that SubIdx"); + unsigned NewReg = MRI->createVirtualRegister(RC); + BuildMI(*MBB, InsertPos, DL, TII->get(TargetOpcode::COPY), NewReg) + .addReg(VReg); + return NewReg; } /// EmitSubregNode - Generate machine code for subreg nodes. /// -void InstrEmitter::EmitSubregNode(SDNode *Node, +void InstrEmitter::EmitSubregNode(SDNode *Node, DenseMap<SDValue, unsigned> &VRBaseMap, bool IsClone, bool IsCloned) { unsigned VRBase = 0; unsigned Opc = Node->getMachineOpcode(); - + // If the node is only used by a CopyToReg and the dest reg is a vreg, use // the CopyToReg'd destination register instead of creating a new vreg. for (SDNode::use_iterator UI = Node->use_begin(), E = Node->use_end(); UI != E; ++UI) { SDNode *User = *UI; - if (User->getOpcode() == ISD::CopyToReg && + if (User->getOpcode() == ISD::CopyToReg && User->getOperand(2).getNode() == Node) { unsigned DestReg = cast<RegisterSDNode>(User->getOperand(1))->getReg(); if (TargetRegisterInfo::isVirtualRegister(DestReg)) { @@ -426,12 +443,14 @@ void InstrEmitter::EmitSubregNode(SDNode *Node, } } } - + if (Opc == TargetOpcode::EXTRACT_SUBREG) { - // EXTRACT_SUBREG is lowered as %dst = COPY %src:sub + // EXTRACT_SUBREG is lowered as %dst = COPY %src:sub. There are no + // constraints on the %dst register, COPY can target all legal register + // classes. unsigned SubIdx = cast<ConstantSDNode>(Node->getOperand(1))->getZExtValue(); + const TargetRegisterClass *TRC = TLI->getRegClassFor(Node->getValueType(0)); - // Figure out the register class to create for the destreg. unsigned VReg = getVR(Node->getOperand(0), VRBaseMap); MachineInstr *DefMI = MRI->getVRegDef(VReg); unsigned SrcReg, DstReg, DefSubIdx; @@ -443,62 +462,57 @@ void InstrEmitter::EmitSubregNode(SDNode *Node, // r1026 = extract_subreg r1025, 4 // to a copy // r1026 = copy r1024 - const TargetRegisterClass *TRC = MRI->getRegClass(SrcReg); VRBase = MRI->createVirtualRegister(TRC); BuildMI(*MBB, InsertPos, Node->getDebugLoc(), TII->get(TargetOpcode::COPY), VRBase).addReg(SrcReg); } else { - const TargetRegisterClass *TRC = MRI->getRegClass(VReg); - const TargetRegisterClass *SRC = TRC->getSubRegisterRegClass(SubIdx); - assert(SRC && "Invalid subregister index in EXTRACT_SUBREG"); - - // Figure out the register class to create for the destreg. - // Note that if we're going to directly use an existing register, - // it must be precisely the required class, and not a subclass - // thereof. - if (VRBase == 0 || SRC != MRI->getRegClass(VRBase)) { - // Create the reg - assert(SRC && "Couldn't find source register class"); - VRBase = MRI->createVirtualRegister(SRC); - } + // VReg may not support a SubIdx sub-register, and we may need to + // constrain its register class or issue a COPY to a compatible register + // class. + VReg = ConstrainForSubReg(VReg, SubIdx, + Node->getOperand(0).getValueType(), + Node->getDebugLoc()); - // Create the extract_subreg machine instruction. - MachineInstr *MI = BuildMI(*MF, Node->getDebugLoc(), - TII->get(TargetOpcode::COPY), VRBase); + // Create the destreg if it is missing. + if (VRBase == 0) + VRBase = MRI->createVirtualRegister(TRC); - // Add source, and subreg index - AddOperand(MI, Node->getOperand(0), 0, 0, VRBaseMap, /*IsDebug=*/false, - IsClone, IsCloned); - assert(TargetRegisterInfo::isVirtualRegister(MI->getOperand(1).getReg())&& - "Cannot yet extract from physregs"); - MI->getOperand(1).setSubReg(SubIdx); - MBB->insert(InsertPos, MI); + // Create the extract_subreg machine instruction. + BuildMI(*MBB, InsertPos, Node->getDebugLoc(), + TII->get(TargetOpcode::COPY), VRBase).addReg(VReg, 0, SubIdx); } } else if (Opc == TargetOpcode::INSERT_SUBREG || Opc == TargetOpcode::SUBREG_TO_REG) { SDValue N0 = Node->getOperand(0); SDValue N1 = Node->getOperand(1); SDValue N2 = Node->getOperand(2); - unsigned SubReg = getVR(N1, VRBaseMap); unsigned SubIdx = cast<ConstantSDNode>(N2)->getZExtValue(); - const TargetRegisterClass *TRC = MRI->getRegClass(SubReg); - const TargetRegisterClass *SRC = - getSuperRegisterRegClass(TRC, SubIdx, Node->getValueType(0)); - - // Figure out the register class to create for the destreg. - // Note that if we're going to directly use an existing register, - // it must be precisely the required class, and not a subclass - // thereof. - if (VRBase == 0 || SRC != MRI->getRegClass(VRBase)) { - // Create the reg - assert(SRC && "Couldn't find source register class"); + + // Figure out the register class to create for the destreg. It should be + // the largest legal register class supporting SubIdx sub-registers. + // RegisterCoalescer will constrain it further if it decides to eliminate + // the INSERT_SUBREG instruction. + // + // %dst = INSERT_SUBREG %src, %sub, SubIdx + // + // is lowered by TwoAddressInstructionPass to: + // + // %dst = COPY %src + // %dst:SubIdx = COPY %sub + // + // There is no constraint on the %src register class. + // + const TargetRegisterClass *SRC = TLI->getRegClassFor(Node->getValueType(0)); + SRC = TRI->getSubClassWithSubReg(SRC, SubIdx); + assert(SRC && "No register class supports VT and SubIdx for INSERT_SUBREG"); + + if (VRBase == 0 || !SRC->hasSubClassEq(MRI->getRegClass(VRBase))) VRBase = MRI->createVirtualRegister(SRC); - } // Create the insert_subreg or subreg_to_reg machine instruction. MachineInstr *MI = BuildMI(*MF, Node->getDebugLoc(), TII->get(Opc)); MI->addOperand(MachineOperand::CreateReg(VRBase, true)); - + // If creating a subreg_to_reg, then the first input operand // is an implicit value immediate, otherwise it's a register if (Opc == TargetOpcode::SUBREG_TO_REG) { @@ -514,7 +528,7 @@ void InstrEmitter::EmitSubregNode(SDNode *Node, MBB->insert(InsertPos, MI); } else llvm_unreachable("Node is not insert_subreg, extract_subreg, or subreg_to_reg"); - + SDValue Op(Node, 0); bool isNew = VRBaseMap.insert(std::make_pair(Op, VRBase)).second; (void)isNew; // Silence compiler warning. @@ -643,9 +657,9 @@ void InstrEmitter:: EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned, DenseMap<SDValue, unsigned> &VRBaseMap) { unsigned Opc = Node->getMachineOpcode(); - + // Handle subreg insert/extract specially - if (Opc == TargetOpcode::EXTRACT_SUBREG || + if (Opc == TargetOpcode::EXTRACT_SUBREG || Opc == TargetOpcode::INSERT_SUBREG || Opc == TargetOpcode::SUBREG_TO_REG) { EmitSubregNode(Node, VRBaseMap, IsClone, IsCloned); @@ -667,7 +681,7 @@ EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned, if (Opc == TargetOpcode::IMPLICIT_DEF) // We want a unique VR for each IMPLICIT_DEF use. return; - + const MCInstrDesc &II = TII->get(Opc); unsigned NumResults = CountResults(Node); unsigned NodeOperands = CountOperands(Node); @@ -712,12 +726,12 @@ EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned, // Then mark unused registers as dead. MI->setPhysRegsDeadExcept(UsedRegs, *TRI); } - + // Add result register values for things that are defined by this // instruction. if (NumResults) CreateVirtualRegisters(Node, MI, II, IsClone, IsCloned, VRBaseMap); - + // Emit all of the actual operands of this instruction, adding them to the // instruction as appropriate. bool HasOptPRefs = II.getNumDefs() > NumResults; @@ -751,7 +765,7 @@ EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned, MI->addRegisterDead(Reg, TRI); } } - + // If the instruction has implicit defs and the node doesn't, mark the // implicit def as dead. If the node has any glue outputs, we don't do this // because we don't know what implicit defs are being used by glued nodes. @@ -761,6 +775,12 @@ EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned, i != e; ++i) MI->addRegisterDead(IDList[i-II.getNumDefs()], TRI); } + + // Run post-isel target hook to adjust this instruction if needed. +#ifdef NDEBUG + if (II.hasPostISelHook()) +#endif + TLI->AdjustInstrPostInstrSelection(MI, Node); } /// EmitSpecialNode - Generate machine code for a target-independent node and @@ -788,7 +808,7 @@ EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned, SrcReg = R->getReg(); else SrcReg = getVR(SrcVal, VRBaseMap); - + unsigned DestReg = cast<RegisterSDNode>(Node->getOperand(1))->getReg(); if (SrcReg == DestReg) // Coalesced away the copy? Ignore. break; @@ -808,12 +828,12 @@ EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned, TII->get(TargetOpcode::EH_LABEL)).addSym(S); break; } - + case ISD::INLINEASM: { unsigned NumOps = Node->getNumOperands(); if (Node->getOperand(NumOps-1).getValueType() == MVT::Glue) --NumOps; // Ignore the glue operand. - + // Create the inline asm machine instruction. MachineInstr *MI = BuildMI(*MF, Node->getDebugLoc(), TII->get(TargetOpcode::INLINEASM)); @@ -822,7 +842,7 @@ EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned, SDValue AsmStrV = Node->getOperand(InlineAsm::Op_AsmString); const char *AsmStr = cast<ExternalSymbolSDNode>(AsmStrV)->getSymbol(); MI->addOperand(MachineOperand::CreateES(AsmStr)); - + // Add the HasSideEffect and isAlignStack bits. int64_t ExtraInfo = cast<ConstantSDNode>(Node->getOperand(InlineAsm::Op_ExtraInfo))-> @@ -834,10 +854,10 @@ EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned, unsigned Flags = cast<ConstantSDNode>(Node->getOperand(i))->getZExtValue(); unsigned NumVals = InlineAsm::getNumOperandRegisters(Flags); - + MI->addOperand(MachineOperand::CreateImm(Flags)); ++i; // Skip the ID value. - + switch (InlineAsm::getKind(Flags)) { default: llvm_unreachable("Bad flags!"); case InlineAsm::Kind_RegDef: @@ -873,13 +893,13 @@ EmitSpecialNode(SDNode *Node, bool IsClone, bool IsCloned, break; } } - + // Get the mdnode from the asm if it exists and add it to the instruction. SDValue MDV = Node->getOperand(InlineAsm::Op_MDNode); const MDNode *MD = cast<MDNodeSDNode>(MDV)->getMD(); if (MD) MI->addOperand(MachineOperand::CreateMetadata(MD)); - + MBB->insert(InsertPos, MI); break; } |