llvm-6502/lib/Target/SystemZ/SystemZISelLowering.h
Richard Sandiford 80a3301b37 [SystemZ] Optimize (sext (ashr (shl ...), ...))
...into (ashr (shl (anyext X), ...), ...), which requires one fewer
instruction.  The (anyext X) can sometimes be simplified too.

I didn't do this in DAGCombiner because widening shifts isn't a win
on all targets.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199114 91177308-0d34-0410-b5e6-96231b3b80d8
2014-01-13 15:17:53 +00:00

334 lines
14 KiB
C++

//===-- SystemZISelLowering.h - SystemZ DAG lowering interface --*- C++ -*-===//
//
// 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 SystemZ uses to lower LLVM code into a
// selection DAG.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_SystemZ_ISELLOWERING_H
#define LLVM_TARGET_SystemZ_ISELLOWERING_H
#include "SystemZ.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/Target/TargetLowering.h"
namespace llvm {
namespace SystemZISD {
enum {
FIRST_NUMBER = ISD::BUILTIN_OP_END,
// Return with a flag operand. Operand 0 is the chain operand.
RET_FLAG,
// Calls a function. Operand 0 is the chain operand and operand 1
// is the target address. The arguments start at operand 2.
// There is an optional glue operand at the end.
CALL,
SIBCALL,
// Wraps a TargetGlobalAddress that should be loaded using PC-relative
// accesses (LARL). Operand 0 is the address.
PCREL_WRAPPER,
// Used in cases where an offset is applied to a TargetGlobalAddress.
// Operand 0 is the full TargetGlobalAddress and operand 1 is a
// PCREL_WRAPPER for an anchor point. This is used so that we can
// cheaply refer to either the full address or the anchor point
// as a register base.
PCREL_OFFSET,
// Integer absolute.
IABS,
// Integer comparisons. There are three operands: the two values
// to compare, and an integer of type SystemZICMP.
ICMP,
// Floating-point comparisons. The two operands are the values to compare.
FCMP,
// Test under mask. The first operand is ANDed with the second operand
// and the condition codes are set on the result. The third operand is
// a boolean that is true if the condition codes need to distinguish
// between CCMASK_TM_MIXED_MSB_0 and CCMASK_TM_MIXED_MSB_1 (which the
// register forms do but the memory forms don't).
TM,
// Branches if a condition is true. Operand 0 is the chain operand;
// operand 1 is the 4-bit condition-code mask, with bit N in
// big-endian order meaning "branch if CC=N"; operand 2 is the
// target block and operand 3 is the flag operand.
BR_CCMASK,
// Selects between operand 0 and operand 1. Operand 2 is the
// mask of condition-code values for which operand 0 should be
// chosen over operand 1; it has the same form as BR_CCMASK.
// Operand 3 is the flag operand.
SELECT_CCMASK,
// Evaluates to the gap between the stack pointer and the
// base of the dynamically-allocatable area.
ADJDYNALLOC,
// Extracts the value of a 32-bit access register. Operand 0 is
// the number of the register.
EXTRACT_ACCESS,
// Wrappers around the ISD opcodes of the same name. The output and
// first input operands are GR128s. The trailing numbers are the
// widths of the second operand in bits.
UMUL_LOHI64,
SDIVREM32,
SDIVREM64,
UDIVREM32,
UDIVREM64,
// Use a series of MVCs to copy bytes from one memory location to another.
// The operands are:
// - the target address
// - the source address
// - the constant length
//
// This isn't a memory opcode because we'd need to attach two
// MachineMemOperands rather than one.
MVC,
// Like MVC, but implemented as a loop that handles X*256 bytes
// followed by straight-line code to handle the rest (if any).
// The value of X is passed as an additional operand.
MVC_LOOP,
// Similar to MVC and MVC_LOOP, but for logic operations (AND, OR, XOR).
NC,
NC_LOOP,
OC,
OC_LOOP,
XC,
XC_LOOP,
// Use CLC to compare two blocks of memory, with the same comments
// as for MVC and MVC_LOOP.
CLC,
CLC_LOOP,
// Use an MVST-based sequence to implement stpcpy().
STPCPY,
// Use a CLST-based sequence to implement strcmp(). The two input operands
// are the addresses of the strings to compare.
STRCMP,
// Use an SRST-based sequence to search a block of memory. The first
// operand is the end address, the second is the start, and the third
// is the character to search for. CC is set to 1 on success and 2
// on failure.
SEARCH_STRING,
// Store the CC value in bits 29 and 28 of an integer.
IPM,
// Perform a serialization operation. (BCR 15,0 or BCR 14,0.)
SERIALIZE,
// Wrappers around the inner loop of an 8- or 16-bit ATOMIC_SWAP or
// ATOMIC_LOAD_<op>.
//
// Operand 0: the address of the containing 32-bit-aligned field
// Operand 1: the second operand of <op>, in the high bits of an i32
// for everything except ATOMIC_SWAPW
// Operand 2: how many bits to rotate the i32 left to bring the first
// operand into the high bits
// Operand 3: the negative of operand 2, for rotating the other way
// Operand 4: the width of the field in bits (8 or 16)
ATOMIC_SWAPW = ISD::FIRST_TARGET_MEMORY_OPCODE,
ATOMIC_LOADW_ADD,
ATOMIC_LOADW_SUB,
ATOMIC_LOADW_AND,
ATOMIC_LOADW_OR,
ATOMIC_LOADW_XOR,
ATOMIC_LOADW_NAND,
ATOMIC_LOADW_MIN,
ATOMIC_LOADW_MAX,
ATOMIC_LOADW_UMIN,
ATOMIC_LOADW_UMAX,
// A wrapper around the inner loop of an ATOMIC_CMP_SWAP.
//
// Operand 0: the address of the containing 32-bit-aligned field
// Operand 1: the compare value, in the low bits of an i32
// Operand 2: the swap value, in the low bits of an i32
// Operand 3: how many bits to rotate the i32 left to bring the first
// operand into the high bits
// Operand 4: the negative of operand 2, for rotating the other way
// Operand 5: the width of the field in bits (8 or 16)
ATOMIC_CMP_SWAPW,
// Prefetch from the second operand using the 4-bit control code in
// the first operand. The code is 1 for a load prefetch and 2 for
// a store prefetch.
PREFETCH
};
// Return true if OPCODE is some kind of PC-relative address.
inline bool isPCREL(unsigned Opcode) {
return Opcode == PCREL_WRAPPER || Opcode == PCREL_OFFSET;
}
}
namespace SystemZICMP {
// Describes whether an integer comparison needs to be signed or unsigned,
// or whether either type is OK.
enum {
Any,
UnsignedOnly,
SignedOnly
};
}
class SystemZSubtarget;
class SystemZTargetMachine;
class SystemZTargetLowering : public TargetLowering {
public:
explicit SystemZTargetLowering(SystemZTargetMachine &TM);
// Override TargetLowering.
virtual MVT getScalarShiftAmountTy(EVT LHSTy) const LLVM_OVERRIDE {
return MVT::i32;
}
virtual EVT getSetCCResultType(LLVMContext &, EVT) const LLVM_OVERRIDE;
virtual bool isFMAFasterThanFMulAndFAdd(EVT VT) const LLVM_OVERRIDE;
virtual bool isFPImmLegal(const APFloat &Imm, EVT VT) const LLVM_OVERRIDE;
virtual bool isLegalAddressingMode(const AddrMode &AM, Type *Ty) const
LLVM_OVERRIDE;
virtual bool allowsUnalignedMemoryAccesses(EVT VT, bool *Fast) const
LLVM_OVERRIDE;
virtual bool isTruncateFree(Type *, Type *) const LLVM_OVERRIDE;
virtual bool isTruncateFree(EVT, EVT) const LLVM_OVERRIDE;
virtual const char *getTargetNodeName(unsigned Opcode) const LLVM_OVERRIDE;
virtual std::pair<unsigned, const TargetRegisterClass *>
getRegForInlineAsmConstraint(const std::string &Constraint,
MVT VT) const LLVM_OVERRIDE;
virtual TargetLowering::ConstraintType
getConstraintType(const std::string &Constraint) const LLVM_OVERRIDE;
virtual TargetLowering::ConstraintWeight
getSingleConstraintMatchWeight(AsmOperandInfo &info,
const char *constraint) const LLVM_OVERRIDE;
virtual void
LowerAsmOperandForConstraint(SDValue Op,
std::string &Constraint,
std::vector<SDValue> &Ops,
SelectionDAG &DAG) const LLVM_OVERRIDE;
virtual MachineBasicBlock *
EmitInstrWithCustomInserter(MachineInstr *MI,
MachineBasicBlock *BB) const LLVM_OVERRIDE;
virtual SDValue LowerOperation(SDValue Op,
SelectionDAG &DAG) const LLVM_OVERRIDE;
virtual bool allowTruncateForTailCall(Type *, Type *) const LLVM_OVERRIDE;
virtual bool mayBeEmittedAsTailCall(CallInst *CI) const LLVM_OVERRIDE;
virtual SDValue
LowerFormalArguments(SDValue Chain,
CallingConv::ID CallConv, bool isVarArg,
const SmallVectorImpl<ISD::InputArg> &Ins,
SDLoc DL, SelectionDAG &DAG,
SmallVectorImpl<SDValue> &InVals) const LLVM_OVERRIDE;
virtual SDValue
LowerCall(CallLoweringInfo &CLI,
SmallVectorImpl<SDValue> &InVals) const LLVM_OVERRIDE;
virtual SDValue
LowerReturn(SDValue Chain,
CallingConv::ID CallConv, bool IsVarArg,
const SmallVectorImpl<ISD::OutputArg> &Outs,
const SmallVectorImpl<SDValue> &OutVals,
SDLoc DL, SelectionDAG &DAG) const LLVM_OVERRIDE;
virtual SDValue prepareVolatileOrAtomicLoad(SDValue Chain, SDLoc DL,
SelectionDAG &DAG) const
LLVM_OVERRIDE;
private:
const SystemZSubtarget &Subtarget;
const SystemZTargetMachine &TM;
// Implement LowerOperation for individual opcodes.
SDValue lowerSETCC(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerBR_CC(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerGlobalAddress(GlobalAddressSDNode *Node,
SelectionDAG &DAG) const;
SDValue lowerGlobalTLSAddress(GlobalAddressSDNode *Node,
SelectionDAG &DAG) const;
SDValue lowerBlockAddress(BlockAddressSDNode *Node,
SelectionDAG &DAG) const;
SDValue lowerJumpTable(JumpTableSDNode *JT, SelectionDAG &DAG) const;
SDValue lowerConstantPool(ConstantPoolSDNode *CP, SelectionDAG &DAG) const;
SDValue lowerVASTART(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerVACOPY(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerSMUL_LOHI(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerUMUL_LOHI(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerSDIVREM(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerUDIVREM(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerBITCAST(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerOR(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerSIGN_EXTEND(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerATOMIC_LOAD(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerATOMIC_STORE(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerATOMIC_LOAD_OP(SDValue Op, SelectionDAG &DAG,
unsigned Opcode) const;
SDValue lowerATOMIC_LOAD_SUB(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerATOMIC_CMP_SWAP(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerLOAD_SEQUENCE_POINT(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerSTACKSAVE(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerSTACKRESTORE(SDValue Op, SelectionDAG &DAG) const;
SDValue lowerPREFETCH(SDValue Op, SelectionDAG &DAG) const;
// If the last instruction before MBBI in MBB was some form of COMPARE,
// try to replace it with a COMPARE AND BRANCH just before MBBI.
// CCMask and Target are the BRC-like operands for the branch.
// Return true if the change was made.
bool convertPrevCompareToBranch(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MBBI,
unsigned CCMask,
MachineBasicBlock *Target) const;
// Implement EmitInstrWithCustomInserter for individual operation types.
MachineBasicBlock *emitSelect(MachineInstr *MI,
MachineBasicBlock *BB) const;
MachineBasicBlock *emitCondStore(MachineInstr *MI,
MachineBasicBlock *BB,
unsigned StoreOpcode, unsigned STOCOpcode,
bool Invert) const;
MachineBasicBlock *emitExt128(MachineInstr *MI,
MachineBasicBlock *MBB,
bool ClearEven, unsigned SubReg) const;
MachineBasicBlock *emitAtomicLoadBinary(MachineInstr *MI,
MachineBasicBlock *BB,
unsigned BinOpcode, unsigned BitSize,
bool Invert = false) const;
MachineBasicBlock *emitAtomicLoadMinMax(MachineInstr *MI,
MachineBasicBlock *MBB,
unsigned CompareOpcode,
unsigned KeepOldMask,
unsigned BitSize) const;
MachineBasicBlock *emitAtomicCmpSwapW(MachineInstr *MI,
MachineBasicBlock *BB) const;
MachineBasicBlock *emitMemMemWrapper(MachineInstr *MI,
MachineBasicBlock *BB,
unsigned Opcode) const;
MachineBasicBlock *emitStringWrapper(MachineInstr *MI,
MachineBasicBlock *BB,
unsigned Opcode) const;
};
} // end namespace llvm
#endif // LLVM_TARGET_SystemZ_ISELLOWERING_H