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llvm-6502/lib/Target/MBlaze/MBlazeISelLowering.cpp
Chandler Carruth 63974b2144 Initial CodeGen support for CTTZ/CTLZ where a zero input produces an 
undefined result. This adds new ISD nodes for the new semantics,
selecting them when the LLVM intrinsic indicates that the undef behavior
is desired. The new nodes expand trivially to the old nodes, so targets
don't actually need to do anything to support these new nodes besides
indicating that they should be expanded. I've done this for all the
operand types that I could figure out for all the targets. Owners of
various targets, please review and let me know if any of these are
incorrect.

Note that the expand behavior is *conservatively correct*, and exactly
matches LLVM's current behavior with these operations. Ideally this
patch will not change behavior in any way. For example the regtest suite
finds the exact same instruction sequences coming out of the code
generator. That's why there are no new tests here -- all of this is
being exercised by the existing test suite.

Thanks to Duncan Sands for reviewing the various bits of this patch and
helping me get the wrinkles ironed out with expanding for each target.
Also thanks to Chris for clarifying through all the discussions that
this is indeed the approach he was looking for. That said, there are
likely still rough spots. Further review much appreciated.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146466 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-13 01:56:10 +00:00

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//===-- MBlazeISelLowering.cpp - MBlaze DAG Lowering Implementation -------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the interfaces that MBlaze uses to lower LLVM code into a
// selection DAG.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "mblaze-lower"
#include "MBlazeISelLowering.h"
#include "MBlazeMachineFunction.h"
#include "MBlazeTargetMachine.h"
#include "MBlazeTargetObjectFile.h"
#include "MBlazeSubtarget.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Intrinsics.h"
#include "llvm/CallingConv.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
static bool CC_MBlaze_AssignReg(unsigned &ValNo, MVT &ValVT, MVT &LocVT,
CCValAssign::LocInfo &LocInfo,
ISD::ArgFlagsTy &ArgFlags,
CCState &State);
const char *MBlazeTargetLowering::getTargetNodeName(unsigned Opcode) const {
switch (Opcode) {
case MBlazeISD::JmpLink : return "MBlazeISD::JmpLink";
case MBlazeISD::GPRel : return "MBlazeISD::GPRel";
case MBlazeISD::Wrap : return "MBlazeISD::Wrap";
case MBlazeISD::ICmp : return "MBlazeISD::ICmp";
case MBlazeISD::Ret : return "MBlazeISD::Ret";
case MBlazeISD::Select_CC : return "MBlazeISD::Select_CC";
default : return NULL;
}
}
MBlazeTargetLowering::MBlazeTargetLowering(MBlazeTargetMachine &TM)
: TargetLowering(TM, new MBlazeTargetObjectFile()) {
Subtarget = &TM.getSubtarget<MBlazeSubtarget>();
// MBlaze does not have i1 type, so use i32 for
// setcc operations results (slt, sgt, ...).
setBooleanContents(ZeroOrOneBooleanContent);
setBooleanVectorContents(ZeroOrOneBooleanContent); // FIXME: Is this correct?
// Set up the register classes
addRegisterClass(MVT::i32, MBlaze::GPRRegisterClass);
if (Subtarget->hasFPU()) {
addRegisterClass(MVT::f32, MBlaze::GPRRegisterClass);
setOperationAction(ISD::ConstantFP, MVT::f32, Legal);
}
// Floating point operations which are not supported
setOperationAction(ISD::FREM, MVT::f32, Expand);
setOperationAction(ISD::FMA, MVT::f32, Expand);
setOperationAction(ISD::UINT_TO_FP, MVT::i8, Expand);
setOperationAction(ISD::UINT_TO_FP, MVT::i16, Expand);
setOperationAction(ISD::UINT_TO_FP, MVT::i32, Expand);
setOperationAction(ISD::FP_TO_UINT, MVT::i32, Expand);
setOperationAction(ISD::FP_ROUND, MVT::f32, Expand);
setOperationAction(ISD::FP_ROUND, MVT::f64, Expand);
setOperationAction(ISD::FCOPYSIGN, MVT::f32, Expand);
setOperationAction(ISD::FCOPYSIGN, MVT::f64, Expand);
setOperationAction(ISD::FSIN, MVT::f32, Expand);
setOperationAction(ISD::FCOS, MVT::f32, Expand);
setOperationAction(ISD::FPOWI, MVT::f32, Expand);
setOperationAction(ISD::FPOW, MVT::f32, Expand);
setOperationAction(ISD::FLOG, MVT::f32, Expand);
setOperationAction(ISD::FLOG2, MVT::f32, Expand);
setOperationAction(ISD::FLOG10, MVT::f32, Expand);
setOperationAction(ISD::FEXP, MVT::f32, Expand);
// Load extented operations for i1 types must be promoted
setLoadExtAction(ISD::EXTLOAD, MVT::i1, Promote);
setLoadExtAction(ISD::ZEXTLOAD, MVT::i1, Promote);
setLoadExtAction(ISD::SEXTLOAD, MVT::i1, Promote);
// Sign extended loads must be expanded
setLoadExtAction(ISD::SEXTLOAD, MVT::i8, Expand);
setLoadExtAction(ISD::SEXTLOAD, MVT::i16, Expand);
// MBlaze has no REM or DIVREM operations.
setOperationAction(ISD::UREM, MVT::i32, Expand);
setOperationAction(ISD::SREM, MVT::i32, Expand);
setOperationAction(ISD::SDIVREM, MVT::i32, Expand);
setOperationAction(ISD::UDIVREM, MVT::i32, Expand);
// If the processor doesn't support multiply then expand it
if (!Subtarget->hasMul()) {
setOperationAction(ISD::MUL, MVT::i32, Expand);
}
// If the processor doesn't support 64-bit multiply then expand
if (!Subtarget->hasMul() || !Subtarget->hasMul64()) {
setOperationAction(ISD::MULHS, MVT::i32, Expand);
setOperationAction(ISD::MULHS, MVT::i64, Expand);
setOperationAction(ISD::MULHU, MVT::i32, Expand);
setOperationAction(ISD::MULHU, MVT::i64, Expand);
}
// If the processor doesn't support division then expand
if (!Subtarget->hasDiv()) {
setOperationAction(ISD::UDIV, MVT::i32, Expand);
setOperationAction(ISD::SDIV, MVT::i32, Expand);
}
// Expand unsupported conversions
setOperationAction(ISD::BITCAST, MVT::f32, Expand);
setOperationAction(ISD::BITCAST, MVT::i32, Expand);
// Expand SELECT_CC
setOperationAction(ISD::SELECT_CC, MVT::Other, Expand);
// MBlaze doesn't have MUL_LOHI
setOperationAction(ISD::SMUL_LOHI, MVT::i32, Expand);
setOperationAction(ISD::UMUL_LOHI, MVT::i32, Expand);
setOperationAction(ISD::SMUL_LOHI, MVT::i64, Expand);
setOperationAction(ISD::UMUL_LOHI, MVT::i64, Expand);
// Used by legalize types to correctly generate the setcc result.
// Without this, every float setcc comes with a AND/OR with the result,
// we don't want this, since the fpcmp result goes to a flag register,
// which is used implicitly by brcond and select operations.
AddPromotedToType(ISD::SETCC, MVT::i1, MVT::i32);
AddPromotedToType(ISD::SELECT, MVT::i1, MVT::i32);
AddPromotedToType(ISD::SELECT_CC, MVT::i1, MVT::i32);
// MBlaze Custom Operations
setOperationAction(ISD::GlobalAddress, MVT::i32, Custom);
setOperationAction(ISD::GlobalTLSAddress, MVT::i32, Custom);
setOperationAction(ISD::JumpTable, MVT::i32, Custom);
setOperationAction(ISD::ConstantPool, MVT::i32, Custom);
// Variable Argument support
setOperationAction(ISD::VASTART, MVT::Other, Custom);
setOperationAction(ISD::VAEND, MVT::Other, Expand);
setOperationAction(ISD::VAARG, MVT::Other, Expand);
setOperationAction(ISD::VACOPY, MVT::Other, Expand);
// Operations not directly supported by MBlaze.
setOperationAction(ISD::DYNAMIC_STACKALLOC, MVT::i32, Expand);
setOperationAction(ISD::BR_JT, MVT::Other, Expand);
setOperationAction(ISD::BR_CC, MVT::Other, Expand);
setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1, Expand);
setOperationAction(ISD::ROTL, MVT::i32, Expand);
setOperationAction(ISD::ROTR, MVT::i32, Expand);
setOperationAction(ISD::SHL_PARTS, MVT::i32, Expand);
setOperationAction(ISD::SRA_PARTS, MVT::i32, Expand);
setOperationAction(ISD::SRL_PARTS, MVT::i32, Expand);
setOperationAction(ISD::CTLZ, MVT::i32, Expand);
setOperationAction(ISD::CTLZ_ZERO_UNDEF, MVT::i32, Expand);
setOperationAction(ISD::CTTZ, MVT::i32, Expand);
setOperationAction(ISD::CTTZ_ZERO_UNDEF, MVT::i32, Expand);
setOperationAction(ISD::CTPOP, MVT::i32, Expand);
setOperationAction(ISD::BSWAP, MVT::i32, Expand);
// We don't have line number support yet.
setOperationAction(ISD::EH_LABEL, MVT::Other, Expand);
// Use the default for now
setOperationAction(ISD::STACKSAVE, MVT::Other, Expand);
setOperationAction(ISD::STACKRESTORE, MVT::Other, Expand);
// MBlaze doesn't have extending float->double load/store
setLoadExtAction(ISD::EXTLOAD, MVT::f32, Expand);
setTruncStoreAction(MVT::f64, MVT::f32, Expand);
setMinFunctionAlignment(2);
setStackPointerRegisterToSaveRestore(MBlaze::R1);
computeRegisterProperties();
}
EVT MBlazeTargetLowering::getSetCCResultType(EVT VT) const {
return MVT::i32;
}
SDValue MBlazeTargetLowering::LowerOperation(SDValue Op,
SelectionDAG &DAG) const {
switch (Op.getOpcode())
{
case ISD::ConstantPool: return LowerConstantPool(Op, DAG);
case ISD::GlobalAddress: return LowerGlobalAddress(Op, DAG);
case ISD::GlobalTLSAddress: return LowerGlobalTLSAddress(Op, DAG);
case ISD::JumpTable: return LowerJumpTable(Op, DAG);
case ISD::SELECT_CC: return LowerSELECT_CC(Op, DAG);
case ISD::VASTART: return LowerVASTART(Op, DAG);
}
return SDValue();
}
//===----------------------------------------------------------------------===//
// Lower helper functions
//===----------------------------------------------------------------------===//
MachineBasicBlock*
MBlazeTargetLowering::EmitInstrWithCustomInserter(MachineInstr *MI,
MachineBasicBlock *MBB)
const {
switch (MI->getOpcode()) {
default: assert(false && "Unexpected instr type to insert");
case MBlaze::ShiftRL:
case MBlaze::ShiftRA:
case MBlaze::ShiftL:
return EmitCustomShift(MI, MBB);
case MBlaze::Select_FCC:
case MBlaze::Select_CC:
return EmitCustomSelect(MI, MBB);
case MBlaze::CAS32:
case MBlaze::SWP32:
case MBlaze::LAA32:
case MBlaze::LAS32:
case MBlaze::LAD32:
case MBlaze::LAO32:
case MBlaze::LAX32:
case MBlaze::LAN32:
return EmitCustomAtomic(MI, MBB);
case MBlaze::MEMBARRIER:
// The Microblaze does not need memory barriers. Just delete the pseudo
// instruction and finish.
MI->eraseFromParent();
return MBB;
}
}
MachineBasicBlock*
MBlazeTargetLowering::EmitCustomShift(MachineInstr *MI,
MachineBasicBlock *MBB) const {
const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
DebugLoc dl = MI->getDebugLoc();
// To "insert" a shift left instruction, we actually have to insert a
// simple loop. The incoming instruction knows the destination vreg to
// set, the source vreg to operate over and the shift amount.
const BasicBlock *LLVM_BB = MBB->getBasicBlock();
MachineFunction::iterator It = MBB;
++It;
// start:
// andi samt, samt, 31
// beqid samt, finish
// add dst, src, r0
// loop:
// addik samt, samt, -1
// sra dst, dst
// bneid samt, loop
// nop
// finish:
MachineFunction *F = MBB->getParent();
MachineRegisterInfo &R = F->getRegInfo();
MachineBasicBlock *loop = F->CreateMachineBasicBlock(LLVM_BB);
MachineBasicBlock *finish = F->CreateMachineBasicBlock(LLVM_BB);
F->insert(It, loop);
F->insert(It, finish);
// Update machine-CFG edges by transferring adding all successors and
// remaining instructions from the current block to the new block which
// will contain the Phi node for the select.
finish->splice(finish->begin(), MBB,
llvm::next(MachineBasicBlock::iterator(MI)),
MBB->end());
finish->transferSuccessorsAndUpdatePHIs(MBB);
// Add the true and fallthrough blocks as its successors.
MBB->addSuccessor(loop);
MBB->addSuccessor(finish);
// Next, add the finish block as a successor of the loop block
loop->addSuccessor(finish);
loop->addSuccessor(loop);
unsigned IAMT = R.createVirtualRegister(MBlaze::GPRRegisterClass);
BuildMI(MBB, dl, TII->get(MBlaze::ANDI), IAMT)
.addReg(MI->getOperand(2).getReg())
.addImm(31);
unsigned IVAL = R.createVirtualRegister(MBlaze::GPRRegisterClass);
BuildMI(MBB, dl, TII->get(MBlaze::ADDIK), IVAL)
.addReg(MI->getOperand(1).getReg())
.addImm(0);
BuildMI(MBB, dl, TII->get(MBlaze::BEQID))
.addReg(IAMT)
.addMBB(finish);
unsigned DST = R.createVirtualRegister(MBlaze::GPRRegisterClass);
unsigned NDST = R.createVirtualRegister(MBlaze::GPRRegisterClass);
BuildMI(loop, dl, TII->get(MBlaze::PHI), DST)
.addReg(IVAL).addMBB(MBB)
.addReg(NDST).addMBB(loop);
unsigned SAMT = R.createVirtualRegister(MBlaze::GPRRegisterClass);
unsigned NAMT = R.createVirtualRegister(MBlaze::GPRRegisterClass);
BuildMI(loop, dl, TII->get(MBlaze::PHI), SAMT)
.addReg(IAMT).addMBB(MBB)
.addReg(NAMT).addMBB(loop);
if (MI->getOpcode() == MBlaze::ShiftL)
BuildMI(loop, dl, TII->get(MBlaze::ADD), NDST).addReg(DST).addReg(DST);
else if (MI->getOpcode() == MBlaze::ShiftRA)
BuildMI(loop, dl, TII->get(MBlaze::SRA), NDST).addReg(DST);
else if (MI->getOpcode() == MBlaze::ShiftRL)
BuildMI(loop, dl, TII->get(MBlaze::SRL), NDST).addReg(DST);
else
llvm_unreachable("Cannot lower unknown shift instruction");
BuildMI(loop, dl, TII->get(MBlaze::ADDIK), NAMT)
.addReg(SAMT)
.addImm(-1);
BuildMI(loop, dl, TII->get(MBlaze::BNEID))
.addReg(NAMT)
.addMBB(loop);
BuildMI(*finish, finish->begin(), dl,
TII->get(MBlaze::PHI), MI->getOperand(0).getReg())
.addReg(IVAL).addMBB(MBB)
.addReg(NDST).addMBB(loop);
// The pseudo instruction is no longer needed so remove it
MI->eraseFromParent();
return finish;
}
MachineBasicBlock*
MBlazeTargetLowering::EmitCustomSelect(MachineInstr *MI,
MachineBasicBlock *MBB) const {
const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
DebugLoc dl = MI->getDebugLoc();
// To "insert" a SELECT_CC instruction, we actually have to insert the
// diamond control-flow pattern. The incoming instruction knows the
// destination vreg to set, the condition code register to branch on, the
// true/false values to select between, and a branch opcode to use.
const BasicBlock *LLVM_BB = MBB->getBasicBlock();
MachineFunction::iterator It = MBB;
++It;
// thisMBB:
// ...
// TrueVal = ...
// setcc r1, r2, r3
// bNE r1, r0, copy1MBB
// fallthrough --> copy0MBB
MachineFunction *F = MBB->getParent();
MachineBasicBlock *flsBB = F->CreateMachineBasicBlock(LLVM_BB);
MachineBasicBlock *dneBB = F->CreateMachineBasicBlock(LLVM_BB);
unsigned Opc;
switch (MI->getOperand(4).getImm()) {
default: llvm_unreachable("Unknown branch condition");
case MBlazeCC::EQ: Opc = MBlaze::BEQID; break;
case MBlazeCC::NE: Opc = MBlaze::BNEID; break;
case MBlazeCC::GT: Opc = MBlaze::BGTID; break;
case MBlazeCC::LT: Opc = MBlaze::BLTID; break;
case MBlazeCC::GE: Opc = MBlaze::BGEID; break;
case MBlazeCC::LE: Opc = MBlaze::BLEID; break;
}
F->insert(It, flsBB);
F->insert(It, dneBB);
// Transfer the remainder of MBB and its successor edges to dneBB.
dneBB->splice(dneBB->begin(), MBB,
llvm::next(MachineBasicBlock::iterator(MI)),
MBB->end());
dneBB->transferSuccessorsAndUpdatePHIs(MBB);
MBB->addSuccessor(flsBB);
MBB->addSuccessor(dneBB);
flsBB->addSuccessor(dneBB);
BuildMI(MBB, dl, TII->get(Opc))
.addReg(MI->getOperand(3).getReg())
.addMBB(dneBB);
// sinkMBB:
// %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
// ...
//BuildMI(dneBB, dl, TII->get(MBlaze::PHI), MI->getOperand(0).getReg())
// .addReg(MI->getOperand(1).getReg()).addMBB(flsBB)
// .addReg(MI->getOperand(2).getReg()).addMBB(BB);
BuildMI(*dneBB, dneBB->begin(), dl,
TII->get(MBlaze::PHI), MI->getOperand(0).getReg())
.addReg(MI->getOperand(2).getReg()).addMBB(flsBB)
.addReg(MI->getOperand(1).getReg()).addMBB(MBB);
MI->eraseFromParent(); // The pseudo instruction is gone now.
return dneBB;
}
MachineBasicBlock*
MBlazeTargetLowering::EmitCustomAtomic(MachineInstr *MI,
MachineBasicBlock *MBB) const {
const TargetInstrInfo *TII = getTargetMachine().getInstrInfo();
DebugLoc dl = MI->getDebugLoc();
// All atomic instructions on the Microblaze are implemented using the
// load-linked / store-conditional style atomic instruction sequences.
// Thus, all operations will look something like the following:
//
// start:
// lwx RV, RP, 0
// <do stuff>
// swx RV, RP, 0
// addic RC, R0, 0
// bneid RC, start
//
// exit:
//
// To "insert" a shift left instruction, we actually have to insert a
// simple loop. The incoming instruction knows the destination vreg to
// set, the source vreg to operate over and the shift amount.
const BasicBlock *LLVM_BB = MBB->getBasicBlock();
MachineFunction::iterator It = MBB;
++It;
// start:
// andi samt, samt, 31
// beqid samt, finish
// add dst, src, r0
// loop:
// addik samt, samt, -1
// sra dst, dst
// bneid samt, loop
// nop
// finish:
MachineFunction *F = MBB->getParent();
MachineRegisterInfo &R = F->getRegInfo();
// Create the start and exit basic blocks for the atomic operation
MachineBasicBlock *start = F->CreateMachineBasicBlock(LLVM_BB);
MachineBasicBlock *exit = F->CreateMachineBasicBlock(LLVM_BB);
F->insert(It, start);
F->insert(It, exit);
// Update machine-CFG edges by transferring adding all successors and
// remaining instructions from the current block to the new block which
// will contain the Phi node for the select.
exit->splice(exit->begin(), MBB, llvm::next(MachineBasicBlock::iterator(MI)),
MBB->end());
exit->transferSuccessorsAndUpdatePHIs(MBB);
// Add the fallthrough block as its successors.
MBB->addSuccessor(start);
BuildMI(start, dl, TII->get(MBlaze::LWX), MI->getOperand(0).getReg())
.addReg(MI->getOperand(1).getReg())
.addReg(MBlaze::R0);
MachineBasicBlock *final = start;
unsigned finalReg = 0;
switch (MI->getOpcode()) {
default: llvm_unreachable("Cannot lower unknown atomic instruction!");
case MBlaze::SWP32:
finalReg = MI->getOperand(2).getReg();
start->addSuccessor(exit);
start->addSuccessor(start);
break;
case MBlaze::LAN32:
case MBlaze::LAX32:
case MBlaze::LAO32:
case MBlaze::LAD32:
case MBlaze::LAS32:
case MBlaze::LAA32: {
unsigned opcode = 0;
switch (MI->getOpcode()) {
default: llvm_unreachable("Cannot lower unknown atomic load!");
case MBlaze::LAA32: opcode = MBlaze::ADDIK; break;
case MBlaze::LAS32: opcode = MBlaze::RSUBIK; break;
case MBlaze::LAD32: opcode = MBlaze::AND; break;
case MBlaze::LAO32: opcode = MBlaze::OR; break;
case MBlaze::LAX32: opcode = MBlaze::XOR; break;
case MBlaze::LAN32: opcode = MBlaze::AND; break;
}
finalReg = R.createVirtualRegister(MBlaze::GPRRegisterClass);
start->addSuccessor(exit);
start->addSuccessor(start);
BuildMI(start, dl, TII->get(opcode), finalReg)
.addReg(MI->getOperand(0).getReg())
.addReg(MI->getOperand(2).getReg());
if (MI->getOpcode() == MBlaze::LAN32) {
unsigned tmp = finalReg;
finalReg = R.createVirtualRegister(MBlaze::GPRRegisterClass);
BuildMI(start, dl, TII->get(MBlaze::XORI), finalReg)
.addReg(tmp)
.addImm(-1);
}
break;
}
case MBlaze::CAS32: {
finalReg = MI->getOperand(3).getReg();
final = F->CreateMachineBasicBlock(LLVM_BB);
F->insert(It, final);
start->addSuccessor(exit);
start->addSuccessor(final);
final->addSuccessor(exit);
final->addSuccessor(start);
unsigned CMP = R.createVirtualRegister(MBlaze::GPRRegisterClass);
BuildMI(start, dl, TII->get(MBlaze::CMP), CMP)
.addReg(MI->getOperand(0).getReg())
.addReg(MI->getOperand(2).getReg());
BuildMI(start, dl, TII->get(MBlaze::BNEID))
.addReg(CMP)
.addMBB(exit);
final->moveAfter(start);
exit->moveAfter(final);
break;
}
}
unsigned CHK = R.createVirtualRegister(MBlaze::GPRRegisterClass);
BuildMI(final, dl, TII->get(MBlaze::SWX))
.addReg(finalReg)
.addReg(MI->getOperand(1).getReg())
.addReg(MBlaze::R0);
BuildMI(final, dl, TII->get(MBlaze::ADDIC), CHK)
.addReg(MBlaze::R0)
.addImm(0);
BuildMI(final, dl, TII->get(MBlaze::BNEID))
.addReg(CHK)
.addMBB(start);
// The pseudo instruction is no longer needed so remove it
MI->eraseFromParent();
return exit;
}
//===----------------------------------------------------------------------===//
// Misc Lower Operation implementation
//===----------------------------------------------------------------------===//
//
SDValue MBlazeTargetLowering::LowerSELECT_CC(SDValue Op,
SelectionDAG &DAG) const {
SDValue LHS = Op.getOperand(0);
SDValue RHS = Op.getOperand(1);
SDValue TrueVal = Op.getOperand(2);
SDValue FalseVal = Op.getOperand(3);
DebugLoc dl = Op.getDebugLoc();
unsigned Opc;
SDValue CompareFlag;
if (LHS.getValueType() == MVT::i32) {
Opc = MBlazeISD::Select_CC;
CompareFlag = DAG.getNode(MBlazeISD::ICmp, dl, MVT::i32, LHS, RHS)
.getValue(1);
} else {
llvm_unreachable("Cannot lower select_cc with unknown type");
}
return DAG.getNode(Opc, dl, TrueVal.getValueType(), TrueVal, FalseVal,
CompareFlag);
}
SDValue MBlazeTargetLowering::
LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const {
// FIXME there isn't actually debug info here
DebugLoc dl = Op.getDebugLoc();
const GlobalValue *GV = cast<GlobalAddressSDNode>(Op)->getGlobal();
SDValue GA = DAG.getTargetGlobalAddress(GV, dl, MVT::i32);
return DAG.getNode(MBlazeISD::Wrap, dl, MVT::i32, GA);
}
SDValue MBlazeTargetLowering::
LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const {
llvm_unreachable("TLS not implemented for MicroBlaze.");
return SDValue(); // Not reached
}
SDValue MBlazeTargetLowering::
LowerJumpTable(SDValue Op, SelectionDAG &DAG) const {
SDValue ResNode;
SDValue HiPart;
// FIXME there isn't actually debug info here
DebugLoc dl = Op.getDebugLoc();
EVT PtrVT = Op.getValueType();
JumpTableSDNode *JT = cast<JumpTableSDNode>(Op);
SDValue JTI = DAG.getTargetJumpTable(JT->getIndex(), PtrVT, 0);
return DAG.getNode(MBlazeISD::Wrap, dl, MVT::i32, JTI);
}
SDValue MBlazeTargetLowering::
LowerConstantPool(SDValue Op, SelectionDAG &DAG) const {
SDValue ResNode;
ConstantPoolSDNode *N = cast<ConstantPoolSDNode>(Op);
const Constant *C = N->getConstVal();
DebugLoc dl = Op.getDebugLoc();
SDValue CP = DAG.getTargetConstantPool(C, MVT::i32, N->getAlignment(),
N->getOffset(), 0);
return DAG.getNode(MBlazeISD::Wrap, dl, MVT::i32, CP);
}
SDValue MBlazeTargetLowering::LowerVASTART(SDValue Op,
SelectionDAG &DAG) const {
MachineFunction &MF = DAG.getMachineFunction();
MBlazeFunctionInfo *FuncInfo = MF.getInfo<MBlazeFunctionInfo>();
DebugLoc dl = Op.getDebugLoc();
SDValue FI = DAG.getFrameIndex(FuncInfo->getVarArgsFrameIndex(),
getPointerTy());
// vastart just stores the address of the VarArgsFrameIndex slot into the
// memory location argument.
const Value *SV = cast<SrcValueSDNode>(Op.getOperand(2))->getValue();
return DAG.getStore(Op.getOperand(0), dl, FI, Op.getOperand(1),
MachinePointerInfo(SV),
false, false, 0);
}
//===----------------------------------------------------------------------===//
// Calling Convention Implementation
//===----------------------------------------------------------------------===//
#include "MBlazeGenCallingConv.inc"
static bool CC_MBlaze_AssignReg(unsigned &ValNo, MVT &ValVT, MVT &LocVT,
CCValAssign::LocInfo &LocInfo,
ISD::ArgFlagsTy &ArgFlags,
CCState &State) {
static const unsigned ArgRegs[] = {
MBlaze::R5, MBlaze::R6, MBlaze::R7,
MBlaze::R8, MBlaze::R9, MBlaze::R10
};
const unsigned NumArgRegs = array_lengthof(ArgRegs);
unsigned Reg = State.AllocateReg(ArgRegs, NumArgRegs);
if (!Reg) return false;
unsigned SizeInBytes = ValVT.getSizeInBits() >> 3;
State.AllocateStack(SizeInBytes, SizeInBytes);
State.addLoc(CCValAssign::getReg(ValNo, ValVT, Reg, LocVT, LocInfo));
return true;
}
//===----------------------------------------------------------------------===//
// Call Calling Convention Implementation
//===----------------------------------------------------------------------===//
/// LowerCall - functions arguments are copied from virtual regs to
/// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted.
/// TODO: isVarArg, isTailCall.
SDValue MBlazeTargetLowering::
LowerCall(SDValue Chain, SDValue Callee, CallingConv::ID CallConv,
bool isVarArg, bool &isTailCall,
const SmallVectorImpl<ISD::OutputArg> &Outs,
const SmallVectorImpl<SDValue> &OutVals,
const SmallVectorImpl<ISD::InputArg> &Ins,
DebugLoc dl, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) const {
// MBlaze does not yet support tail call optimization
isTailCall = false;
// The MBlaze requires stack slots for arguments passed to var arg
// functions even if they are passed in registers.
bool needsRegArgSlots = isVarArg;
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo *MFI = MF.getFrameInfo();
const TargetFrameLowering &TFI = *MF.getTarget().getFrameLowering();
// Analyze operands of the call, assigning locations to each operand.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(),
getTargetMachine(), ArgLocs, *DAG.getContext());
CCInfo.AnalyzeCallOperands(Outs, CC_MBlaze);
// Get a count of how many bytes are to be pushed on the stack.
unsigned NumBytes = CCInfo.getNextStackOffset();
// Variable argument function calls require a minimum of 24-bytes of stack
if (isVarArg && NumBytes < 24) NumBytes = 24;
Chain = DAG.getCALLSEQ_START(Chain, DAG.getIntPtrConstant(NumBytes, true));
SmallVector<std::pair<unsigned, SDValue>, 8> RegsToPass;
SmallVector<SDValue, 8> MemOpChains;
// Walk the register/memloc assignments, inserting copies/loads.
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
CCValAssign &VA = ArgLocs[i];
MVT RegVT = VA.getLocVT();
SDValue Arg = OutVals[i];
// Promote the value if needed.
switch (VA.getLocInfo()) {
default: llvm_unreachable("Unknown loc info!");
case CCValAssign::Full: break;
case CCValAssign::SExt:
Arg = DAG.getNode(ISD::SIGN_EXTEND, dl, RegVT, Arg);
break;
case CCValAssign::ZExt:
Arg = DAG.getNode(ISD::ZERO_EXTEND, dl, RegVT, Arg);
break;
case CCValAssign::AExt:
Arg = DAG.getNode(ISD::ANY_EXTEND, dl, RegVT, Arg);
break;
}
// Arguments that can be passed on register must be kept at
// RegsToPass vector
if (VA.isRegLoc()) {
RegsToPass.push_back(std::make_pair(VA.getLocReg(), Arg));
} else {
// Register can't get to this point...
assert(VA.isMemLoc());
// Since we are alread passing values on the stack we don't
// need to worry about creating additional slots for the
// values passed via registers.
needsRegArgSlots = false;
// Create the frame index object for this incoming parameter
unsigned ArgSize = VA.getValVT().getSizeInBits()/8;
unsigned StackLoc = VA.getLocMemOffset() + 4;
int FI = MFI->CreateFixedObject(ArgSize, StackLoc, true);
SDValue PtrOff = DAG.getFrameIndex(FI,getPointerTy());
// emit ISD::STORE whichs stores the
// parameter value to a stack Location
MemOpChains.push_back(DAG.getStore(Chain, dl, Arg, PtrOff,
MachinePointerInfo(),
false, false, 0));
}
}
// If we need to reserve stack space for the arguments passed via registers
// then create a fixed stack object at the beginning of the stack.
if (needsRegArgSlots && TFI.hasReservedCallFrame(MF))
MFI->CreateFixedObject(28,0,true);
// Transform all store nodes into one single node because all store
// nodes are independent of each other.
if (!MemOpChains.empty())
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
&MemOpChains[0], MemOpChains.size());
// Build a sequence of copy-to-reg nodes chained together with token
// chain and flag operands which copy the outgoing args into registers.
// The InFlag in necessary since all emitted instructions must be
// stuck together.
SDValue InFlag;
for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
Chain = DAG.getCopyToReg(Chain, dl, RegsToPass[i].first,
RegsToPass[i].second, InFlag);
InFlag = Chain.getValue(1);
}
// If the callee is a GlobalAddress/ExternalSymbol node (quite common, every
// direct call is) turn it into a TargetGlobalAddress/TargetExternalSymbol
// node so that legalize doesn't hack it.
if (GlobalAddressSDNode *G = dyn_cast<GlobalAddressSDNode>(Callee))
Callee = DAG.getTargetGlobalAddress(G->getGlobal(), dl,
getPointerTy(), 0, 0);
else if (ExternalSymbolSDNode *S = dyn_cast<ExternalSymbolSDNode>(Callee))
Callee = DAG.getTargetExternalSymbol(S->getSymbol(),
getPointerTy(), 0);
// MBlazeJmpLink = #chain, #target_address, #opt_in_flags...
// = Chain, Callee, Reg#1, Reg#2, ...
//
// Returns a chain & a flag for retval copy to use.
SDVTList NodeTys = DAG.getVTList(MVT::Other, MVT::Glue);
SmallVector<SDValue, 8> Ops;
Ops.push_back(Chain);
Ops.push_back(Callee);
// Add argument registers to the end of the list so that they are
// known live into the call.
for (unsigned i = 0, e = RegsToPass.size(); i != e; ++i) {
Ops.push_back(DAG.getRegister(RegsToPass[i].first,
RegsToPass[i].second.getValueType()));
}
if (InFlag.getNode())
Ops.push_back(InFlag);
Chain = DAG.getNode(MBlazeISD::JmpLink, dl, NodeTys, &Ops[0], Ops.size());
InFlag = Chain.getValue(1);
// Create the CALLSEQ_END node.
Chain = DAG.getCALLSEQ_END(Chain, DAG.getIntPtrConstant(NumBytes, true),
DAG.getIntPtrConstant(0, true), InFlag);
if (!Ins.empty())
InFlag = Chain.getValue(1);
// Handle result values, copying them out of physregs into vregs that we
// return.
return LowerCallResult(Chain, InFlag, CallConv, isVarArg,
Ins, dl, DAG, InVals);
}
/// LowerCallResult - Lower the result values of a call into the
/// appropriate copies out of appropriate physical registers.
SDValue MBlazeTargetLowering::
LowerCallResult(SDValue Chain, SDValue InFlag, CallingConv::ID CallConv,
bool isVarArg, const SmallVectorImpl<ISD::InputArg> &Ins,
DebugLoc dl, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) const {
// Assign locations to each value returned by this call.
SmallVector<CCValAssign, 16> RVLocs;
CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(),
getTargetMachine(), RVLocs, *DAG.getContext());
CCInfo.AnalyzeCallResult(Ins, RetCC_MBlaze);
// Copy all of the result registers out of their specified physreg.
for (unsigned i = 0; i != RVLocs.size(); ++i) {
Chain = DAG.getCopyFromReg(Chain, dl, RVLocs[i].getLocReg(),
RVLocs[i].getValVT(), InFlag).getValue(1);
InFlag = Chain.getValue(2);
InVals.push_back(Chain.getValue(0));
}
return Chain;
}
//===----------------------------------------------------------------------===//
// Formal Arguments Calling Convention Implementation
//===----------------------------------------------------------------------===//
/// LowerFormalArguments - transform physical registers into
/// virtual registers and generate load operations for
/// arguments places on the stack.
SDValue MBlazeTargetLowering::
LowerFormalArguments(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins,
DebugLoc dl, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) const {
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo *MFI = MF.getFrameInfo();
MBlazeFunctionInfo *MBlazeFI = MF.getInfo<MBlazeFunctionInfo>();
unsigned StackReg = MF.getTarget().getRegisterInfo()->getFrameRegister(MF);
MBlazeFI->setVarArgsFrameIndex(0);
// Used with vargs to acumulate store chains.
std::vector<SDValue> OutChains;
// Keep track of the last register used for arguments
unsigned ArgRegEnd = 0;
// Assign locations to all of the incoming arguments.
SmallVector<CCValAssign, 16> ArgLocs;
CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(),
getTargetMachine(), ArgLocs, *DAG.getContext());
CCInfo.AnalyzeFormalArguments(Ins, CC_MBlaze);
SDValue StackPtr;
for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
CCValAssign &VA = ArgLocs[i];
// Arguments stored on registers
if (VA.isRegLoc()) {
MVT RegVT = VA.getLocVT();
ArgRegEnd = VA.getLocReg();
TargetRegisterClass *RC = 0;
if (RegVT == MVT::i32)
RC = MBlaze::GPRRegisterClass;
else if (RegVT == MVT::f32)
RC = MBlaze::GPRRegisterClass;
else
llvm_unreachable("RegVT not supported by LowerFormalArguments");
// Transform the arguments stored on
// physical registers into virtual ones
unsigned Reg = MF.addLiveIn(ArgRegEnd, RC);
SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, Reg, RegVT);
// If this is an 8 or 16-bit value, it has been passed promoted
// to 32 bits. Insert an assert[sz]ext to capture this, then
// truncate to the right size. If if is a floating point value
// then convert to the correct type.
if (VA.getLocInfo() != CCValAssign::Full) {
unsigned Opcode = 0;
if (VA.getLocInfo() == CCValAssign::SExt)
Opcode = ISD::AssertSext;
else if (VA.getLocInfo() == CCValAssign::ZExt)
Opcode = ISD::AssertZext;
if (Opcode)
ArgValue = DAG.getNode(Opcode, dl, RegVT, ArgValue,
DAG.getValueType(VA.getValVT()));
ArgValue = DAG.getNode(ISD::TRUNCATE, dl, VA.getValVT(), ArgValue);
}
InVals.push_back(ArgValue);
} else { // VA.isRegLoc()
// sanity check
assert(VA.isMemLoc());
// The last argument is not a register
ArgRegEnd = 0;
// The stack pointer offset is relative to the caller stack frame.
// Since the real stack size is unknown here, a negative SPOffset
// is used so there's a way to adjust these offsets when the stack
// size get known (on EliminateFrameIndex). A dummy SPOffset is
// used instead of a direct negative address (which is recorded to
// be used on emitPrologue) to avoid mis-calc of the first stack
// offset on PEI::calculateFrameObjectOffsets.
// Arguments are always 32-bit.
unsigned ArgSize = VA.getLocVT().getSizeInBits()/8;
unsigned StackLoc = VA.getLocMemOffset() + 4;
int FI = MFI->CreateFixedObject(ArgSize, 0, true);
MBlazeFI->recordLoadArgsFI(FI, -StackLoc);
MBlazeFI->recordLiveIn(FI);
// Create load nodes to retrieve arguments from the stack
SDValue FIN = DAG.getFrameIndex(FI, getPointerTy());
InVals.push_back(DAG.getLoad(VA.getValVT(), dl, Chain, FIN,
MachinePointerInfo::getFixedStack(FI),
false, false, false, 0));
}
}
// To meet ABI, when VARARGS are passed on registers, the registers
// must have their values written to the caller stack frame. If the last
// argument was placed in the stack, there's no need to save any register.
if ((isVarArg) && ArgRegEnd) {
if (StackPtr.getNode() == 0)
StackPtr = DAG.getRegister(StackReg, getPointerTy());
// The last register argument that must be saved is MBlaze::R10
TargetRegisterClass *RC = MBlaze::GPRRegisterClass;
unsigned Begin = getMBlazeRegisterNumbering(MBlaze::R5);
unsigned Start = getMBlazeRegisterNumbering(ArgRegEnd+1);
unsigned End = getMBlazeRegisterNumbering(MBlaze::R10);
unsigned StackLoc = Start - Begin + 1;
for (; Start <= End; ++Start, ++StackLoc) {
unsigned Reg = getMBlazeRegisterFromNumbering(Start);
unsigned LiveReg = MF.addLiveIn(Reg, RC);
SDValue ArgValue = DAG.getCopyFromReg(Chain, dl, LiveReg, MVT::i32);
int FI = MFI->CreateFixedObject(4, 0, true);
MBlazeFI->recordStoreVarArgsFI(FI, -(StackLoc*4));
SDValue PtrOff = DAG.getFrameIndex(FI, getPointerTy());
OutChains.push_back(DAG.getStore(Chain, dl, ArgValue, PtrOff,
MachinePointerInfo(),
false, false, 0));
// Record the frame index of the first variable argument
// which is a value necessary to VASTART.
if (!MBlazeFI->getVarArgsFrameIndex())
MBlazeFI->setVarArgsFrameIndex(FI);
}
}
// All stores are grouped in one node to allow the matching between
// the size of Ins and InVals. This only happens when on varg functions
if (!OutChains.empty()) {
OutChains.push_back(Chain);
Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
&OutChains[0], OutChains.size());
}
return Chain;
}
//===----------------------------------------------------------------------===//
// Return Value Calling Convention Implementation
//===----------------------------------------------------------------------===//
SDValue MBlazeTargetLowering::
LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs,
const SmallVectorImpl<SDValue> &OutVals,
DebugLoc dl, SelectionDAG &DAG) const {
// CCValAssign - represent the assignment of
// the return value to a location
SmallVector<CCValAssign, 16> RVLocs;
// CCState - Info about the registers and stack slot.
CCState CCInfo(CallConv, isVarArg, DAG.getMachineFunction(),
getTargetMachine(), RVLocs, *DAG.getContext());
// Analize return values.
CCInfo.AnalyzeReturn(Outs, RetCC_MBlaze);
// If this is the first return lowered for this function, add
// the regs to the liveout set for the function.
if (DAG.getMachineFunction().getRegInfo().liveout_empty()) {
for (unsigned i = 0; i != RVLocs.size(); ++i)
if (RVLocs[i].isRegLoc())
DAG.getMachineFunction().getRegInfo().addLiveOut(RVLocs[i].getLocReg());
}
SDValue Flag;
// Copy the result values into the output registers.
for (unsigned i = 0; i != RVLocs.size(); ++i) {
CCValAssign &VA = RVLocs[i];
assert(VA.isRegLoc() && "Can only return in registers!");
Chain = DAG.getCopyToReg(Chain, dl, VA.getLocReg(),
OutVals[i], Flag);
// guarantee that all emitted copies are
// stuck together, avoiding something bad
Flag = Chain.getValue(1);
}
// If this function is using the interrupt_handler calling convention
// then use "rtid r14, 0" otherwise use "rtsd r15, 8"
unsigned Ret = (CallConv == llvm::CallingConv::MBLAZE_INTR) ? MBlazeISD::IRet
: MBlazeISD::Ret;
unsigned Reg = (CallConv == llvm::CallingConv::MBLAZE_INTR) ? MBlaze::R14
: MBlaze::R15;
SDValue DReg = DAG.getRegister(Reg, MVT::i32);
if (Flag.getNode())
return DAG.getNode(Ret, dl, MVT::Other, Chain, DReg, Flag);
return DAG.getNode(Ret, dl, MVT::Other, Chain, DReg);
}
//===----------------------------------------------------------------------===//
// MBlaze Inline Assembly Support
//===----------------------------------------------------------------------===//
/// getConstraintType - Given a constraint letter, return the type of
/// constraint it is for this target.
MBlazeTargetLowering::ConstraintType MBlazeTargetLowering::
getConstraintType(const std::string &Constraint) const
{
// MBlaze specific constrainy
//
// 'd' : An address register. Equivalent to r.
// 'y' : Equivalent to r; retained for
// backwards compatibility.
// 'f' : Floating Point registers.
if (Constraint.size() == 1) {
switch (Constraint[0]) {
default : break;
case 'd':
case 'y':
case 'f':
return C_RegisterClass;
break;
}
}
return TargetLowering::getConstraintType(Constraint);
}
/// Examine constraint type and operand type and determine a weight value.
/// This object must already have been set up with the operand type
/// and the current alternative constraint selected.
TargetLowering::ConstraintWeight
MBlazeTargetLowering::getSingleConstraintMatchWeight(
AsmOperandInfo &info, const char *constraint) const {
ConstraintWeight weight = CW_Invalid;
Value *CallOperandVal = info.CallOperandVal;
// If we don't have a value, we can't do a match,
// but allow it at the lowest weight.
if (CallOperandVal == NULL)
return CW_Default;
Type *type = CallOperandVal->getType();
// Look at the constraint type.
switch (*constraint) {
default:
weight = TargetLowering::getSingleConstraintMatchWeight(info, constraint);
break;
case 'd':
case 'y':
if (type->isIntegerTy())
weight = CW_Register;
break;
case 'f':
if (type->isFloatTy())
weight = CW_Register;
break;
}
return weight;
}
/// Given a register class constraint, like 'r', if this corresponds directly
/// to an LLVM register class, return a register of 0 and the register class
/// pointer.
std::pair<unsigned, const TargetRegisterClass*> MBlazeTargetLowering::
getRegForInlineAsmConstraint(const std::string &Constraint, EVT VT) const {
if (Constraint.size() == 1) {
switch (Constraint[0]) {
case 'r':
return std::make_pair(0U, MBlaze::GPRRegisterClass);
// TODO: These can't possibly be right, but match what was in
// getRegClassForInlineAsmConstraint.
case 'd':
case 'y':
case 'f':
if (VT == MVT::f32)
return std::make_pair(0U, MBlaze::GPRRegisterClass);
}
}
return TargetLowering::getRegForInlineAsmConstraint(Constraint, VT);
}
bool MBlazeTargetLowering::
isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
// The MBlaze target isn't yet aware of offsets.
return false;
}
bool MBlazeTargetLowering::isFPImmLegal(const APFloat &Imm, EVT VT) const {
return VT != MVT::f32;
}
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