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llvm-6502/lib/Target/IA64/IA64ISelDAGToDAG.cpp
Duraid Madina d525df3c27 add support for storing and returning bools 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24228 91177308-0d34-0410-b5e6-96231b3b80d8
2005-11-07 03:11:02 +00:00

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//===---- IA64ISelDAGToDAG.cpp - IA64 pattern matching inst selector ------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Duraid Madina and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines a pattern matching instruction selector for IA64,
// converting a legalized dag to an IA64 dag.
//
//===----------------------------------------------------------------------===//
#include "IA64.h"
#include "IA64TargetMachine.h"
#include "IA64ISelLowering.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/SSARegMap.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SelectionDAGISel.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Constants.h"
#include "llvm/GlobalValue.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MathExtras.h"
using namespace llvm;
namespace {
Statistic<> FusedFP ("ia64-codegen", "Number of fused fp operations");
Statistic<> FrameOff("ia64-codegen", "Number of frame idx offsets collapsed");
//===--------------------------------------------------------------------===//
/// IA64DAGToDAGISel - IA64 specific code to select IA64 machine
/// instructions for SelectionDAG operations.
///
class IA64DAGToDAGISel : public SelectionDAGISel {
IA64TargetLowering IA64Lowering;
unsigned GlobalBaseReg;
public:
IA64DAGToDAGISel(TargetMachine &TM)
: SelectionDAGISel(IA64Lowering), IA64Lowering(TM) {}
virtual bool runOnFunction(Function &Fn) {
// Make sure we re-emit a set of the global base reg if necessary
GlobalBaseReg = 0;
return SelectionDAGISel::runOnFunction(Fn);
}
/// getI64Imm - Return a target constant with the specified value, of type
/// i64.
inline SDOperand getI64Imm(uint64_t Imm) {
return CurDAG->getTargetConstant(Imm, MVT::i64);
}
/// getGlobalBaseReg - insert code into the entry mbb to materialize the PIC
/// base register. Return the virtual register that holds this value.
// SDOperand getGlobalBaseReg(); TODO: hmm
// Select - Convert the specified operand from a target-independent to a
// target-specific node if it hasn't already been changed.
SDOperand Select(SDOperand Op);
SDNode *SelectIntImmediateExpr(SDOperand LHS, SDOperand RHS,
unsigned OCHi, unsigned OCLo,
bool IsArithmetic = false,
bool Negate = false);
SDNode *SelectBitfieldInsert(SDNode *N);
/// SelectCC - Select a comparison of the specified values with the
/// specified condition code, returning the CR# of the expression.
SDOperand SelectCC(SDOperand LHS, SDOperand RHS, ISD::CondCode CC);
/// SelectAddr - Given the specified address, return the two operands for a
/// load/store instruction, and return true if it should be an indexed [r+r]
/// operation.
bool SelectAddr(SDOperand Addr, SDOperand &Op1, SDOperand &Op2);
SDOperand BuildSDIVSequence(SDNode *N);
SDOperand BuildUDIVSequence(SDNode *N);
/// InstructionSelectBasicBlock - This callback is invoked by
/// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
virtual void InstructionSelectBasicBlock(SelectionDAG &DAG);
virtual const char *getPassName() const {
return "IA64 (Itanium) DAG->DAG Instruction Selector";
}
// Include the pieces autogenerated from the target description.
#include "IA64GenDAGISel.inc"
private:
SDOperand SelectCALL(SDOperand Op);
};
}
/// InstructionSelectBasicBlock - This callback is invoked by
/// SelectionDAGISel when it has created a SelectionDAG for us to codegen.
void IA64DAGToDAGISel::InstructionSelectBasicBlock(SelectionDAG &DAG) {
DEBUG(BB->dump());
// The selection process is inherently a bottom-up recursive process (users
// select their uses before themselves). Given infinite stack space, we
// could just start selecting on the root and traverse the whole graph. In
// practice however, this causes us to run out of stack space on large basic
// blocks. To avoid this problem, select the entry node, then all its uses,
// iteratively instead of recursively.
std::vector<SDOperand> Worklist;
Worklist.push_back(DAG.getEntryNode());
// Note that we can do this in the IA64 target (scanning forward across token
// chain edges) because no nodes ever get folded across these edges. On a
// target like X86 which supports load/modify/store operations, this would
// have to be more careful.
while (!Worklist.empty()) {
SDOperand Node = Worklist.back();
Worklist.pop_back();
// Chose from the least deep of the top two nodes.
if (!Worklist.empty() &&
Worklist.back().Val->getNodeDepth() < Node.Val->getNodeDepth())
std::swap(Worklist.back(), Node);
if ((Node.Val->getOpcode() >= ISD::BUILTIN_OP_END &&
Node.Val->getOpcode() < IA64ISD::FIRST_NUMBER) ||
CodeGenMap.count(Node)) continue;
for (SDNode::use_iterator UI = Node.Val->use_begin(),
E = Node.Val->use_end(); UI != E; ++UI) {
// Scan the values. If this use has a value that is a token chain, add it
// to the worklist.
SDNode *User = *UI;
for (unsigned i = 0, e = User->getNumValues(); i != e; ++i)
if (User->getValueType(i) == MVT::Other) {
Worklist.push_back(SDOperand(User, i));
break;
}
}
// Finally, legalize this node.
Select(Node);
}
// Select target instructions for the DAG.
DAG.setRoot(Select(DAG.getRoot()));
CodeGenMap.clear();
DAG.RemoveDeadNodes();
// Emit machine code to BB.
ScheduleAndEmitDAG(DAG);
}
SDOperand IA64DAGToDAGISel::SelectCALL(SDOperand Op) {
SDNode *N = Op.Val;
SDOperand Chain = Select(N->getOperand(0));
unsigned CallOpcode;
std::vector<SDOperand> CallOperands;
// save the current GP, SP and RP : FIXME: do we need to do all 3 always?
SDOperand GPBeforeCall = CurDAG->getCopyFromReg(Chain, IA64::r1, MVT::i64);
Chain = GPBeforeCall.getValue(1);
SDOperand SPBeforeCall = CurDAG->getCopyFromReg(Chain, IA64::r12, MVT::i64);
Chain = SPBeforeCall.getValue(1);
SDOperand RPBeforeCall = CurDAG->getCopyFromReg(Chain, IA64::rp, MVT::i64);
Chain = RPBeforeCall.getValue(1);
// if we can call directly, do so
if (GlobalAddressSDNode *GASD =
dyn_cast<GlobalAddressSDNode>(N->getOperand(1))) {
CallOpcode = IA64::BRCALL_IPREL;
CallOperands.push_back(CurDAG->getTargetGlobalAddress(GASD->getGlobal(),
MVT::i64));
} else if (ExternalSymbolSDNode *ESSDN = // FIXME: we currently NEED this
// case for correctness, to avoid
// "non-pic code with imm reloc.n
// against dynamic symbol" errors
dyn_cast<ExternalSymbolSDNode>(N->getOperand(1))) {
CallOpcode = IA64::BRCALL_IPREL;
CallOperands.push_back(N->getOperand(1));
} else {
// otherwise we need to load the function descriptor,
// load the branch target (function)'s entry point and GP,
// branch (call) then restore the GP
SDOperand FnDescriptor = Select(N->getOperand(1));
// load the branch target's entry point [mem] and
// GP value [mem+8]
SDOperand targetEntryPoint=CurDAG->getTargetNode(IA64::LD8, MVT::i64,
FnDescriptor);
Chain = targetEntryPoint.getValue(1);
SDOperand targetGPAddr=CurDAG->getTargetNode(IA64::ADDS, MVT::i64,
FnDescriptor, CurDAG->getConstant(8, MVT::i64));
Chain = targetGPAddr.getValue(1);
SDOperand targetGP=CurDAG->getTargetNode(IA64::LD8, MVT::i64,
targetGPAddr);
Chain = targetGP.getValue(1);
/* FIXME? (methcall still fails)
SDOperand targetEntryPoint=CurDAG->getLoad(MVT::i64, Chain, FnDescriptor,
CurDAG->getSrcValue(0));
SDOperand targetGPAddr=CurDAG->getNode(ISD::ADD, MVT::i64, FnDescriptor,
CurDAG->getConstant(8, MVT::i64));
SDOperand targetGP=CurDAG->getLoad(MVT::i64, Chain, targetGPAddr,
CurDAG->getSrcValue(0));
*/
/* this is just the long way of writing the two lines below?
// Copy the callee GP into r1
SDOperand r1 = CurDAG->getRegister(IA64::r1, MVT::i64);
Chain = CurDAG->getNode(ISD::CopyToReg, MVT::i64, Chain, r1,
targetGP);
// Copy the callee address into the b6 branch register
SDOperand B6 = CurDAG->getRegister(IA64::B6, MVT::i64);
Chain = CurDAG->getNode(ISD::CopyToReg, MVT::i64, Chain, B6,
targetEntryPoint);
*/
Chain = CurDAG->getCopyToReg(Chain, IA64::r1, targetGP);
Chain = CurDAG->getCopyToReg(Chain, IA64::B6, targetEntryPoint);
CallOperands.push_back(CurDAG->getRegister(IA64::B6, MVT::i64));
CallOpcode = IA64::BRCALL_INDIRECT;
}
// see section 8.5.8 of "Itanium Software Conventions and
// Runtime Architecture Guide to see some examples of what's going
// on here. (in short: int args get mapped 1:1 'slot-wise' to out0->out7,
// while FP args get mapped to F8->F15 as needed)
// TODO: support in-memory arguments
unsigned used_FPArgs=0; // how many FP args have been used so far?
unsigned intArgs[] = {IA64::out0, IA64::out1, IA64::out2, IA64::out3,
IA64::out4, IA64::out5, IA64::out6, IA64::out7 };
unsigned FPArgs[] = {IA64::F8, IA64::F9, IA64::F10, IA64::F11,
IA64::F12, IA64::F13, IA64::F14, IA64::F15 };
SDOperand InFlag; // Null incoming flag value.
for (unsigned i = 2, e = N->getNumOperands(); i != e; ++i) {
unsigned DestReg = 0;
MVT::ValueType RegTy = N->getOperand(i).getValueType();
if (RegTy == MVT::i64) {
assert((i-2) < 8 && "Too many int args");
DestReg = intArgs[i-2];
} else {
assert(MVT::isFloatingPoint(N->getOperand(i).getValueType()) &&
"Unpromoted integer arg?");
assert(used_FPArgs < 8 && "Too many fp args");
DestReg = FPArgs[used_FPArgs++];
}
if (N->getOperand(i).getOpcode() != ISD::UNDEF) {
SDOperand Val = Select(N->getOperand(i));
if(MVT::isInteger(N->getOperand(i).getValueType())) {
Chain = CurDAG->getCopyToReg(Chain, DestReg, Val, InFlag);
InFlag = Chain.getValue(1);
CallOperands.push_back(CurDAG->getRegister(DestReg, RegTy));
}
// some functions (e.g. printf) want floating point arguments
// *also* passed as in-memory representations in integer registers
// this is FORTRAN legacy junk which we don't _always_ need
// to do, but to be on the safe side, we do.
else if(MVT::isFloatingPoint(N->getOperand(i).getValueType())) {
assert((i-2) < 8 && "FP args alone would fit, but no int regs left");
// first copy into the appropriate FP reg
Chain = CurDAG->getCopyToReg(Chain, DestReg, Val);
// then copy into the appropriate integer reg
DestReg = intArgs[i-2];
// GETFD takes an FP reg and writes a GP reg
Chain = CurDAG->getTargetNode(IA64::GETFD, MVT::i64, Val);
// FIXME: this next line is a bit unfortunate
Chain = CurDAG->getCopyToReg(Chain, DestReg, Chain, InFlag);
InFlag = Chain.getValue(1);
CallOperands.push_back(CurDAG->getRegister(DestReg, MVT::i64));
}
}
}
// Finally, once everything is in registers to pass to the call, emit the
// call itself.
if (InFlag.Val)
CallOperands.push_back(InFlag); // Strong dep on register copies.
else
CallOperands.push_back(Chain); // Weak dep on whatever occurs before
Chain = CurDAG->getTargetNode(CallOpcode, MVT::Other, MVT::Flag,
CallOperands);
std::vector<SDOperand> CallResults;
// If the call has results, copy the values out of the ret val registers.
switch (N->getValueType(0)) {
default: assert(0 && "Unexpected ret value!");
case MVT::Other: break;
case MVT::i1: {
// bools are returned as bytes 0/1 in r8
SDOperand byteval = CurDAG->getCopyFromReg(Chain, IA64::r8, MVT::i64,
Chain.getValue(1));
Chain = byteval.getValue(1);
Chain = CurDAG->getTargetNode(IA64::CMPNE, MVT::i1, MVT::Other,
byteval, CurDAG->getRegister(IA64::r0, MVT::i64)).getValue(1);
CallResults.push_back(Chain.getValue(0));
break;
}
case MVT::i64:
Chain = CurDAG->getCopyFromReg(Chain, IA64::r8, MVT::i64,
Chain.getValue(1)).getValue(1);
CallResults.push_back(Chain.getValue(0));
break;
case MVT::f64:
Chain = CurDAG->getCopyFromReg(Chain, IA64::F8, N->getValueType(0),
Chain.getValue(1)).getValue(1);
CallResults.push_back(Chain.getValue(0));
break;
}
// restore GP, SP and RP - FIXME: this doesn't quite work (e.g.
// methcall / objinst both segfault on exit) and it *really*
// doesn't work unless you have -sched=none
Chain = CurDAG->getCopyToReg(Chain, IA64::r1, GPBeforeCall);
Chain = CurDAG->getCopyToReg(Chain, IA64::r12, SPBeforeCall);
Chain = CurDAG->getCopyToReg(Chain, IA64::rp, RPBeforeCall);
CallResults.push_back(Chain); // llc segfaults w/o this,
// ary3(e.g.) SIGILLs with 3
for (unsigned i = 0, e = CallResults.size(); i != e; ++i)
CodeGenMap[Op.getValue(i)] = CallResults[i];
return CallResults[Op.ResNo];
}
// Select - Convert the specified operand from a target-independent to a
// target-specific node if it hasn't already been changed.
SDOperand IA64DAGToDAGISel::Select(SDOperand Op) {
SDNode *N = Op.Val;
if (N->getOpcode() >= ISD::BUILTIN_OP_END &&
N->getOpcode() < IA64ISD::FIRST_NUMBER)
return Op; // Already selected.
// If this has already been converted, use it.
std::map<SDOperand, SDOperand>::iterator CGMI = CodeGenMap.find(Op);
if (CGMI != CodeGenMap.end()) return CGMI->second;
switch (N->getOpcode()) {
default: break;
case ISD::CALL:
case ISD::TAILCALL: return SelectCALL(Op);
/* todo:
* case ISD::DYNAMIC_STACKALLOC:
*/
case ISD::ConstantFP: {
SDOperand Chain = CurDAG->getEntryNode(); // this is a constant, so..
if (cast<ConstantFPSDNode>(N)->isExactlyValue(+0.0))
return CurDAG->getCopyFromReg(Chain, IA64::F0, MVT::f64);
else if (cast<ConstantFPSDNode>(N)->isExactlyValue(+1.0))
return CurDAG->getCopyFromReg(Chain, IA64::F1, MVT::f64);
else
assert(0 && "Unexpected FP constant!");
}
case ISD::FrameIndex: { // TODO: reduce creepyness
int FI = cast<FrameIndexSDNode>(N)->getIndex();
if (N->hasOneUse()) {
CurDAG->SelectNodeTo(N, IA64::MOV, MVT::i64,
CurDAG->getTargetFrameIndex(FI, MVT::i64));
return SDOperand(N, 0);
}
return CurDAG->getTargetNode(IA64::MOV, MVT::i64,
CurDAG->getTargetFrameIndex(FI, MVT::i64));
}
case ISD::ConstantPool: {
Constant *C = cast<ConstantPoolSDNode>(N)->get();
SDOperand CPI = CurDAG->getTargetConstantPool(C, MVT::i64);
return CurDAG->getTargetNode(IA64::ADDL_GA, MVT::i64, // ?
CurDAG->getRegister(IA64::r1, MVT::i64), CPI);
}
case ISD::GlobalAddress: {
GlobalValue *GV = cast<GlobalAddressSDNode>(N)->getGlobal();
SDOperand GA = CurDAG->getTargetGlobalAddress(GV, MVT::i64);
SDOperand Tmp = CurDAG->getTargetNode(IA64::ADDL_GA, MVT::i64,
CurDAG->getRegister(IA64::r1, MVT::i64), GA);
return CurDAG->getTargetNode(IA64::LD8, MVT::i64, Tmp);
}
case ISD::LOAD:
case ISD::EXTLOAD:
case ISD::ZEXTLOAD: {
SDOperand Chain = Select(N->getOperand(0));
SDOperand Address = Select(N->getOperand(1));
MVT::ValueType TypeBeingLoaded = (N->getOpcode() == ISD::LOAD) ?
N->getValueType(0) : cast<VTSDNode>(N->getOperand(3))->getVT();
unsigned Opc;
switch (TypeBeingLoaded) {
default: N->dump(); assert(0 && "Cannot load this type!");
case MVT::i1: { // this is a bool
Opc = IA64::LD1; // first we load a byte, then compare for != 0
CurDAG->SelectNodeTo(N, IA64::CMPNE, MVT::i1, MVT::Other,
CurDAG->getTargetNode(Opc, MVT::i64, Address),
CurDAG->getRegister(IA64::r0, MVT::i64), Chain);
return SDOperand(N, Op.ResNo); // XXX: early exit
}
case MVT::i8: Opc = IA64::LD1; break;
case MVT::i16: Opc = IA64::LD2; break;
case MVT::i32: Opc = IA64::LD4; break;
case MVT::i64: Opc = IA64::LD8; break;
case MVT::f32: Opc = IA64::LDF4; break;
case MVT::f64: Opc = IA64::LDF8; break;
}
CurDAG->SelectNodeTo(N, Opc, N->getValueType(0), MVT::Other,
Address, Chain); // TODO: comment this
return SDOperand(N, Op.ResNo);
}
case ISD::TRUNCSTORE:
case ISD::STORE: {
SDOperand Address = Select(N->getOperand(2));
SDOperand Chain = Select(N->getOperand(0));
unsigned Opc;
if (N->getOpcode() == ISD::STORE) {
switch (N->getOperand(1).getValueType()) {
default: assert(0 && "unknown type in store");
case MVT::i1: { // this is a bool
Opc = IA64::ST1; // we store either 0 or 1 as a byte
CurDAG->SelectNodeTo(N, Opc, MVT::Other, Address,
CurDAG->getTargetNode(IA64::PADDS, MVT::i64,
CurDAG->getRegister(IA64::r0, MVT::i64),
CurDAG->getConstant(1, MVT::i64),
Select(N->getOperand(1))),
Chain);
return SDOperand(N, 0); // XXX: early exit
}
case MVT::i64: Opc = IA64::ST8; break;
case MVT::f64: Opc = IA64::STF8; break;
}
} else { //ISD::TRUNCSTORE
switch(cast<VTSDNode>(N->getOperand(4))->getVT()) {
default: assert(0 && "unknown type in truncstore");
case MVT::i8: Opc = IA64::ST1; break;
case MVT::i16: Opc = IA64::ST2; break;
case MVT::i32: Opc = IA64::ST4; break;
case MVT::f32: Opc = IA64::STF4; break;
}
}
CurDAG->SelectNodeTo(N, Opc, MVT::Other, Select(N->getOperand(2)),
Select(N->getOperand(1)), Chain);
return SDOperand(N, 0);
}
case ISD::BRCOND: {
SDOperand Chain = Select(N->getOperand(0));
SDOperand CC = Select(N->getOperand(1));
MachineBasicBlock *Dest =
cast<BasicBlockSDNode>(N->getOperand(2))->getBasicBlock();
//FIXME - we do NOT need long branches all the time
CurDAG->SelectNodeTo(N, IA64::BRLCOND_NOTCALL, MVT::Other, CC, CurDAG->getBasicBlock(Dest), Chain);
return SDOperand(N, 0);
}
case ISD::CALLSEQ_START:
case ISD::CALLSEQ_END: {
int64_t Amt = cast<ConstantSDNode>(N->getOperand(1))->getValue();
unsigned Opc = N->getOpcode() == ISD::CALLSEQ_START ?
IA64::ADJUSTCALLSTACKDOWN : IA64::ADJUSTCALLSTACKUP;
CurDAG->SelectNodeTo(N, Opc, MVT::Other,
getI64Imm(Amt), Select(N->getOperand(0)));
return SDOperand(N, 0);
}
case ISD::RET: {
SDOperand Chain = Select(N->getOperand(0)); // Token chain.
switch (N->getNumOperands()) {
default:
assert(0 && "Unknown return instruction!");
case 2: {
SDOperand RetVal = Select(N->getOperand(1));
switch (RetVal.getValueType()) {
default: assert(0 && "I don't know how to return this type! (promote?)");
// FIXME: do I need to add support for bools here?
// (return '0' or '1' in r8, basically...)
//
// FIXME: need to round floats - 80 bits is bad, the tester
// told me so
case MVT::i64:
// we mark r8 as live on exit up above in LowerArguments()
// BuildMI(BB, IA64::MOV, 1, IA64::r8).addReg(Tmp1);
Chain = CurDAG->getCopyToReg(Chain, IA64::r8, RetVal);
break;
case MVT::f64:
// we mark F8 as live on exit up above in LowerArguments()
// BuildMI(BB, IA64::FMOV, 1, IA64::F8).addReg(Tmp1);
Chain = CurDAG->getCopyToReg(Chain, IA64::F8, RetVal);
break;
}
break;
}
case 1:
break;
}
// we need to copy VirtGPR (the vreg (to become a real reg)) that holds
// the output of this function's alloc instruction back into ar.pfs
// before we return. this copy must not float up above the last
// outgoing call in this function!!!
SDOperand AR_PFSVal = CurDAG->getCopyFromReg(Chain, IA64Lowering.VirtGPR,
MVT::i64);
Chain = AR_PFSVal.getValue(1);
Chain = CurDAG->getCopyToReg(Chain, IA64::AR_PFS, AR_PFSVal);
CurDAG->SelectNodeTo(N, IA64::RET, MVT::Other, Chain); // and then just emit a 'ret' instruction
// before returning, restore the ar.pfs register (set by the 'alloc' up top)
// BuildMI(BB, IA64::MOV, 1).addReg(IA64::AR_PFS).addReg(IA64Lowering.VirtGPR);
//
return SDOperand(N, 0);
}
case ISD::BR:
// FIXME: we don't need long branches all the time!
CurDAG->SelectNodeTo(N, IA64::BRL_NOTCALL, MVT::Other, N->getOperand(1),
Select(N->getOperand(0)));
return SDOperand(N, 0);
}
return SelectCode(Op);
}
/// createIA64DAGToDAGInstructionSelector - This pass converts a legalized DAG
/// into an IA64-specific DAG, ready for instruction scheduling.
///
FunctionPass *llvm::createIA64DAGToDAGInstructionSelector(TargetMachine &TM) {
return new IA64DAGToDAGISel(TM);
}
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