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llvm-6502/lib/Target/PowerPC/PPCISelLowering.cpp
Jim Laskey ad23c9d4f2 Make UINT_TO_FP and SINT_TO_FP use generic expansion. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22815 91177308-0d34-0410-b5e6-96231b3b80d8
2005-08-17 00:40:22 +00:00

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//===-- PPC32ISelLowering.cpp - PPC32 DAG Lowering Implementation ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the PPC32ISelLowering class.
//
//===----------------------------------------------------------------------===//
#include "PPC32ISelLowering.h"
#include "PPC32TargetMachine.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/Function.h"
using namespace llvm;
PPC32TargetLowering::PPC32TargetLowering(TargetMachine &TM)
: TargetLowering(TM) {
// Fold away setcc operations if possible.
setSetCCIsExpensive();
// Set up the register classes.
addRegisterClass(MVT::i32, PPC32::GPRCRegisterClass);
addRegisterClass(MVT::f32, PPC32::FPRCRegisterClass);
addRegisterClass(MVT::f64, PPC32::FPRCRegisterClass);
// PowerPC has no intrinsics for these particular operations
setOperationAction(ISD::MEMMOVE, MVT::Other, Expand);
setOperationAction(ISD::MEMSET, MVT::Other, Expand);
setOperationAction(ISD::MEMCPY, MVT::Other, Expand);
// PowerPC has an i16 but no i8 (or i1) SEXTLOAD
setOperationAction(ISD::SEXTLOAD, MVT::i1, Expand);
setOperationAction(ISD::SEXTLOAD, MVT::i8, Expand);
// PowerPC has no SREM/UREM instructions
setOperationAction(ISD::SREM, MVT::i32, Expand);
setOperationAction(ISD::UREM, MVT::i32, Expand);
// We don't support sin/cos/sqrt/fmod
setOperationAction(ISD::FSIN , MVT::f64, Expand);
setOperationAction(ISD::FCOS , MVT::f64, Expand);
setOperationAction(ISD::SREM , MVT::f64, Expand);
setOperationAction(ISD::FSIN , MVT::f32, Expand);
setOperationAction(ISD::FCOS , MVT::f32, Expand);
setOperationAction(ISD::SREM , MVT::f32, Expand);
// If we're enabling GP optimizations, use hardware square root
if (!TM.getSubtarget<PPCSubtarget>().isGigaProcessor()) {
setOperationAction(ISD::FSQRT, MVT::f64, Expand);
setOperationAction(ISD::FSQRT, MVT::f32, Expand);
}
// PowerPC does not have CTPOP or CTTZ
setOperationAction(ISD::CTPOP, MVT::i32 , Expand);
setOperationAction(ISD::CTTZ , MVT::i32 , Expand);
// PowerPC does not have Select
setOperationAction(ISD::SELECT, MVT::i32, Expand);
setOperationAction(ISD::SELECT, MVT::f32, Expand);
setOperationAction(ISD::SELECT, MVT::f64, Expand);
// PowerPC does not have BRCOND* which requires SetCC
setOperationAction(ISD::BRCOND, MVT::Other, Expand);
setOperationAction(ISD::BRCONDTWOWAY, MVT::Other, Expand);
// PowerPC does not have FP_TO_UINT
setOperationAction(ISD::FP_TO_UINT, MVT::i32, Expand);
// PowerPC does not have [U|S]INT_TO_FP
setOperationAction(ISD::SINT_TO_FP, MVT::i32, Expand);
setOperationAction(ISD::UINT_TO_FP, MVT::i32, Expand);
setSetCCResultContents(ZeroOrOneSetCCResult);
addLegalFPImmediate(+0.0); // Necessary for FSEL
addLegalFPImmediate(-0.0); //
computeRegisterProperties();
}
std::vector<SDOperand>
PPC32TargetLowering::LowerArguments(Function &F, SelectionDAG &DAG) {
//
// add beautiful description of PPC stack frame format, or at least some docs
//
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo *MFI = MF.getFrameInfo();
MachineBasicBlock& BB = MF.front();
std::vector<SDOperand> ArgValues;
// Due to the rather complicated nature of the PowerPC ABI, rather than a
// fixed size array of physical args, for the sake of simplicity let the STL
// handle tracking them for us.
std::vector<unsigned> argVR, argPR, argOp;
unsigned ArgOffset = 24;
unsigned GPR_remaining = 8;
unsigned FPR_remaining = 13;
unsigned GPR_idx = 0, FPR_idx = 0;
static const unsigned GPR[] = {
PPC::R3, PPC::R4, PPC::R5, PPC::R6,
PPC::R7, PPC::R8, PPC::R9, PPC::R10,
};
static const unsigned FPR[] = {
PPC::F1, PPC::F2, PPC::F3, PPC::F4, PPC::F5, PPC::F6, PPC::F7,
PPC::F8, PPC::F9, PPC::F10, PPC::F11, PPC::F12, PPC::F13
};
// Add DAG nodes to load the arguments... On entry to a function on PPC,
// the arguments start at offset 24, although they are likely to be passed
// in registers.
for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I) {
SDOperand newroot, argt;
unsigned ObjSize;
bool needsLoad = false;
bool ArgLive = !I->use_empty();
MVT::ValueType ObjectVT = getValueType(I->getType());
switch (ObjectVT) {
default: assert(0 && "Unhandled argument type!");
case MVT::i1:
case MVT::i8:
case MVT::i16:
case MVT::i32:
ObjSize = 4;
if (!ArgLive) break;
if (GPR_remaining > 0) {
MF.addLiveIn(GPR[GPR_idx]);
argt = newroot = DAG.getCopyFromReg(DAG.getRoot(),
GPR[GPR_idx], MVT::i32);
if (ObjectVT != MVT::i32)
argt = DAG.getNode(ISD::TRUNCATE, ObjectVT, newroot);
} else {
needsLoad = true;
}
break;
case MVT::i64: ObjSize = 8;
if (!ArgLive) break;
if (GPR_remaining > 0) {
SDOperand argHi, argLo;
MF.addLiveIn(GPR[GPR_idx]);
argHi = DAG.getCopyFromReg(DAG.getRoot(), GPR[GPR_idx], MVT::i32);
// If we have two or more remaining argument registers, then both halves
// of the i64 can be sourced from there. Otherwise, the lower half will
// have to come off the stack. This can happen when an i64 is preceded
// by 28 bytes of arguments.
if (GPR_remaining > 1) {
MF.addLiveIn(GPR[GPR_idx+1]);
argLo = DAG.getCopyFromReg(argHi, GPR[GPR_idx+1], MVT::i32);
} else {
int FI = MFI->CreateFixedObject(4, ArgOffset+4);
SDOperand FIN = DAG.getFrameIndex(FI, MVT::i32);
argLo = DAG.getLoad(MVT::i32, DAG.getEntryNode(), FIN,
DAG.getSrcValue(NULL));
}
// Build the outgoing arg thingy
argt = DAG.getNode(ISD::BUILD_PAIR, MVT::i64, argLo, argHi);
newroot = argLo;
} else {
needsLoad = true;
}
break;
case MVT::f32:
case MVT::f64:
ObjSize = (ObjectVT == MVT::f64) ? 8 : 4;
if (!ArgLive) break;
if (FPR_remaining > 0) {
MF.addLiveIn(FPR[FPR_idx]);
argt = newroot = DAG.getCopyFromReg(DAG.getRoot(),
FPR[FPR_idx], ObjectVT);
--FPR_remaining;
++FPR_idx;
} else {
needsLoad = true;
}
break;
}
// We need to load the argument to a virtual register if we determined above
// that we ran out of physical registers of the appropriate type
if (needsLoad) {
unsigned SubregOffset = 0;
if (ObjectVT == MVT::i8 || ObjectVT == MVT::i1) SubregOffset = 3;
if (ObjectVT == MVT::i16) SubregOffset = 2;
int FI = MFI->CreateFixedObject(ObjSize, ArgOffset);
SDOperand FIN = DAG.getFrameIndex(FI, MVT::i32);
FIN = DAG.getNode(ISD::ADD, MVT::i32, FIN,
DAG.getConstant(SubregOffset, MVT::i32));
argt = newroot = DAG.getLoad(ObjectVT, DAG.getEntryNode(), FIN,
DAG.getSrcValue(NULL));
}
// Every 4 bytes of argument space consumes one of the GPRs available for
// argument passing.
if (GPR_remaining > 0) {
unsigned delta = (GPR_remaining > 1 && ObjSize == 8) ? 2 : 1;
GPR_remaining -= delta;
GPR_idx += delta;
}
ArgOffset += ObjSize;
if (newroot.Val)
DAG.setRoot(newroot.getValue(1));
ArgValues.push_back(argt);
}
// If the function takes variable number of arguments, make a frame index for
// the start of the first vararg value... for expansion of llvm.va_start.
if (F.isVarArg()) {
VarArgsFrameIndex = MFI->CreateFixedObject(4, ArgOffset);
SDOperand FIN = DAG.getFrameIndex(VarArgsFrameIndex, MVT::i32);
// If this function is vararg, store any remaining integer argument regs
// to their spots on the stack so that they may be loaded by deferencing the
// result of va_next.
std::vector<SDOperand> MemOps;
for (; GPR_remaining > 0; --GPR_remaining, ++GPR_idx) {
MF.addLiveIn(GPR[GPR_idx]);
SDOperand Val = DAG.getCopyFromReg(DAG.getRoot(), GPR[GPR_idx], MVT::i32);
SDOperand Store = DAG.getNode(ISD::STORE, MVT::Other, Val.getValue(1),
Val, FIN, DAG.getSrcValue(NULL));
MemOps.push_back(Store);
// Increment the address by four for the next argument to store
SDOperand PtrOff = DAG.getConstant(4, getPointerTy());
FIN = DAG.getNode(ISD::ADD, MVT::i32, FIN, PtrOff);
}
DAG.setRoot(DAG.getNode(ISD::TokenFactor, MVT::Other, MemOps));
}
// Finally, inform the code generator which regs we return values in.
switch (getValueType(F.getReturnType())) {
default: assert(0 && "Unknown type!");
case MVT::isVoid: break;
case MVT::i1:
case MVT::i8:
case MVT::i16:
case MVT::i32:
MF.addLiveOut(PPC::R3);
break;
case MVT::i64:
MF.addLiveOut(PPC::R3);
MF.addLiveOut(PPC::R4);
break;
case MVT::f32:
case MVT::f64:
MF.addLiveOut(PPC::F1);
break;
}
return ArgValues;
}
std::pair<SDOperand, SDOperand>
PPC32TargetLowering::LowerCallTo(SDOperand Chain,
const Type *RetTy, bool isVarArg,
unsigned CallingConv, bool isTailCall,
SDOperand Callee, ArgListTy &Args,
SelectionDAG &DAG) {
// args_to_use will accumulate outgoing args for the ISD::CALL case in
// SelectExpr to use to put the arguments in the appropriate registers.
std::vector<SDOperand> args_to_use;
// Count how many bytes are to be pushed on the stack, including the linkage
// area, and parameter passing area.
unsigned NumBytes = 24;
if (Args.empty()) {
Chain = DAG.getNode(ISD::CALLSEQ_START, MVT::Other, Chain,
DAG.getConstant(NumBytes, getPointerTy()));
} else {
for (unsigned i = 0, e = Args.size(); i != e; ++i)
switch (getValueType(Args[i].second)) {
default: assert(0 && "Unknown value type!");
case MVT::i1:
case MVT::i8:
case MVT::i16:
case MVT::i32:
case MVT::f32:
NumBytes += 4;
break;
case MVT::i64:
case MVT::f64:
NumBytes += 8;
break;
}
// Just to be safe, we'll always reserve the full 24 bytes of linkage area
// plus 32 bytes of argument space in case any called code gets funky on us.
// (Required by ABI to support var arg)
if (NumBytes < 56) NumBytes = 56;
// Adjust the stack pointer for the new arguments...
// These operations are automatically eliminated by the prolog/epilog pass
Chain = DAG.getNode(ISD::CALLSEQ_START, MVT::Other, Chain,
DAG.getConstant(NumBytes, getPointerTy()));
// Set up a copy of the stack pointer for use loading and storing any
// arguments that may not fit in the registers available for argument
// passing.
SDOperand StackPtr = DAG.getCopyFromReg(DAG.getEntryNode(),
PPC::R1, MVT::i32);
// Figure out which arguments are going to go in registers, and which in
// memory. Also, if this is a vararg function, floating point operations
// must be stored to our stack, and loaded into integer regs as well, if
// any integer regs are available for argument passing.
unsigned ArgOffset = 24;
unsigned GPR_remaining = 8;
unsigned FPR_remaining = 13;
std::vector<SDOperand> MemOps;
for (unsigned i = 0, e = Args.size(); i != e; ++i) {
// PtrOff will be used to store the current argument to the stack if a
// register cannot be found for it.
SDOperand PtrOff = DAG.getConstant(ArgOffset, getPointerTy());
PtrOff = DAG.getNode(ISD::ADD, MVT::i32, StackPtr, PtrOff);
MVT::ValueType ArgVT = getValueType(Args[i].second);
switch (ArgVT) {
default: assert(0 && "Unexpected ValueType for argument!");
case MVT::i1:
case MVT::i8:
case MVT::i16:
// Promote the integer to 32 bits. If the input type is signed use a
// sign extend, otherwise use a zero extend.
if (Args[i].second->isSigned())
Args[i].first =DAG.getNode(ISD::SIGN_EXTEND, MVT::i32, Args[i].first);
else
Args[i].first =DAG.getNode(ISD::ZERO_EXTEND, MVT::i32, Args[i].first);
// FALL THROUGH
case MVT::i32:
if (GPR_remaining > 0) {
args_to_use.push_back(Args[i].first);
--GPR_remaining;
} else {
MemOps.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
Args[i].first, PtrOff,
DAG.getSrcValue(NULL)));
}
ArgOffset += 4;
break;
case MVT::i64:
// If we have one free GPR left, we can place the upper half of the i64
// in it, and store the other half to the stack. If we have two or more
// free GPRs, then we can pass both halves of the i64 in registers.
if (GPR_remaining > 0) {
SDOperand Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32,
Args[i].first, DAG.getConstant(1, MVT::i32));
SDOperand Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, MVT::i32,
Args[i].first, DAG.getConstant(0, MVT::i32));
args_to_use.push_back(Hi);
--GPR_remaining;
if (GPR_remaining > 0) {
args_to_use.push_back(Lo);
--GPR_remaining;
} else {
SDOperand ConstFour = DAG.getConstant(4, getPointerTy());
PtrOff = DAG.getNode(ISD::ADD, MVT::i32, PtrOff, ConstFour);
MemOps.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
Lo, PtrOff, DAG.getSrcValue(NULL)));
}
} else {
MemOps.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
Args[i].first, PtrOff,
DAG.getSrcValue(NULL)));
}
ArgOffset += 8;
break;
case MVT::f32:
case MVT::f64:
if (FPR_remaining > 0) {
args_to_use.push_back(Args[i].first);
--FPR_remaining;
if (isVarArg) {
SDOperand Store = DAG.getNode(ISD::STORE, MVT::Other, Chain,
Args[i].first, PtrOff,
DAG.getSrcValue(NULL));
MemOps.push_back(Store);
// Float varargs are always shadowed in available integer registers
if (GPR_remaining > 0) {
SDOperand Load = DAG.getLoad(MVT::i32, Store, PtrOff,
DAG.getSrcValue(NULL));
MemOps.push_back(Load);
args_to_use.push_back(Load);
--GPR_remaining;
}
if (GPR_remaining > 0 && MVT::f64 == ArgVT) {
SDOperand ConstFour = DAG.getConstant(4, getPointerTy());
PtrOff = DAG.getNode(ISD::ADD, MVT::i32, PtrOff, ConstFour);
SDOperand Load = DAG.getLoad(MVT::i32, Store, PtrOff,
DAG.getSrcValue(NULL));
MemOps.push_back(Load);
args_to_use.push_back(Load);
--GPR_remaining;
}
} else {
// If we have any FPRs remaining, we may also have GPRs remaining.
// Args passed in FPRs consume either 1 (f32) or 2 (f64) available
// GPRs.
if (GPR_remaining > 0) {
args_to_use.push_back(DAG.getNode(ISD::UNDEF, MVT::i32));
--GPR_remaining;
}
if (GPR_remaining > 0 && MVT::f64 == ArgVT) {
args_to_use.push_back(DAG.getNode(ISD::UNDEF, MVT::i32));
--GPR_remaining;
}
}
} else {
MemOps.push_back(DAG.getNode(ISD::STORE, MVT::Other, Chain,
Args[i].first, PtrOff,
DAG.getSrcValue(NULL)));
}
ArgOffset += (ArgVT == MVT::f32) ? 4 : 8;
break;
}
}
if (!MemOps.empty())
Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, MemOps);
}
std::vector<MVT::ValueType> RetVals;
MVT::ValueType RetTyVT = getValueType(RetTy);
if (RetTyVT != MVT::isVoid)
RetVals.push_back(RetTyVT);
RetVals.push_back(MVT::Other);
SDOperand TheCall = SDOperand(DAG.getCall(RetVals,
Chain, Callee, args_to_use), 0);
Chain = TheCall.getValue(RetTyVT != MVT::isVoid);
Chain = DAG.getNode(ISD::CALLSEQ_END, MVT::Other, Chain,
DAG.getConstant(NumBytes, getPointerTy()));
return std::make_pair(TheCall, Chain);
}
SDOperand PPC32TargetLowering::LowerVAStart(SDOperand Chain, SDOperand VAListP,
Value *VAListV, SelectionDAG &DAG) {
// vastart just stores the address of the VarArgsFrameIndex slot into the
// memory location argument.
SDOperand FR = DAG.getFrameIndex(VarArgsFrameIndex, MVT::i32);
return DAG.getNode(ISD::STORE, MVT::Other, Chain, FR, VAListP,
DAG.getSrcValue(VAListV));
}
std::pair<SDOperand,SDOperand>
PPC32TargetLowering::LowerVAArg(SDOperand Chain,
SDOperand VAListP, Value *VAListV,
const Type *ArgTy, SelectionDAG &DAG) {
MVT::ValueType ArgVT = getValueType(ArgTy);
SDOperand VAList =
DAG.getLoad(MVT::i32, Chain, VAListP, DAG.getSrcValue(VAListV));
SDOperand Result = DAG.getLoad(ArgVT, Chain, VAList, DAG.getSrcValue(NULL));
unsigned Amt;
if (ArgVT == MVT::i32 || ArgVT == MVT::f32)
Amt = 4;
else {
assert((ArgVT == MVT::i64 || ArgVT == MVT::f64) &&
"Other types should have been promoted for varargs!");
Amt = 8;
}
VAList = DAG.getNode(ISD::ADD, VAList.getValueType(), VAList,
DAG.getConstant(Amt, VAList.getValueType()));
Chain = DAG.getNode(ISD::STORE, MVT::Other, Chain,
VAList, VAListP, DAG.getSrcValue(VAListV));
return std::make_pair(Result, Chain);
}
std::pair<SDOperand, SDOperand> PPC32TargetLowering::
LowerFrameReturnAddress(bool isFrameAddress, SDOperand Chain, unsigned Depth,
SelectionDAG &DAG) {
assert(0 && "LowerFrameReturnAddress unimplemented");
abort();
}
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