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llvm-mirror/test/TableGen/DAGDefaultOps.td
Simon Tatham b8c33a2f38 [TableGen] Allow DAG isel patterns to override default operands.
When a Tablegen instruction description uses `OperandWithDefaultOps`,
isel patterns for that instruction don't have to fill in the default
value for the operand in question. But the flip side is that they
actually //can't// override the defaults even if they want to.

This will be very inconvenient for the Arm backend, when we start
wanting to write isel patterns that generate the many MVE predicated
vector instructions, in the form with predication actually enabled. So
this small Tablegen fix makes it possible to write an isel pattern
either with or without values for a defaulted operand, and have the
default values filled in only if they are not overridden.

If all the defaulted operands come at the end of the instruction's
operand list, there's a natural way to match them up to the arguments
supplied in the pattern: consume pattern arguments until you run out,
then fill in any missing instruction operands with their default
values. But if defaulted and non-defaulted operands are interleaved,
it's less clear what to do. This does happen in existing targets (the
first example I came across was KILLGT, in the AMDGPU/R600 backend),
and of course they expect the previous behaviour (that the default for
those operands is used and a pattern argument is not consumed), so for
backwards compatibility I've stuck with that.

Reviewers: nhaehnle, hfinkel, dmgreen

Subscribers: mehdi_amini, javed.absar, tpr, kristof.beyls, steven_wu, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63814

llvm-svn: 365114
2019-07-04 08:43:20 +00:00

109 lines
3.5 KiB
TableGen

// RUN: llvm-tblgen -gen-dag-isel -I %p/../../include %s -o %t
// RUN: FileCheck --check-prefix=ADD %s < %t
// RUN: FileCheck --check-prefix=ADDINT %s < %t
// RUN: FileCheck --check-prefix=SUB %s < %t
// RUN: FileCheck --check-prefix=MULINT %s < %t
include "llvm/Target/Target.td"
def TestInstrInfo : InstrInfo;
def TestTarget : Target {
let InstructionSet = TestInstrInfo;
}
class TestEncoding : Instruction {
field bits<32> Inst;
}
class TestReg<int index> : Register<"R"#index, []> {
let HWEncoding{15-4} = 0;
let HWEncoding{3-0} = !cast<bits<4>>(index);
}
foreach i = 0-15 in
def "R"#i : TestReg<i>;
def Reg : RegisterClass<"TestTarget", [i32], 32, (sequence "R%d", 0, 15)>;
def IntOperand: Operand<i32>;
def OptionalIntOperand: OperandWithDefaultOps<i32, (ops (i32 0))>;
class RRI<string Mnemonic, bits<4> Opcode> : TestEncoding {
dag OutOperandList = (outs Reg:$dest);
dag InOperandList = (ins Reg:$src1, Reg:$src2, OptionalIntOperand:$imm);
string AsmString = Mnemonic # " $dest1, $src1, $src2, #$imm";
string AsmVariantName = "";
field bits<4> dest;
field bits<4> src1;
field bits<4> src2;
field bits<16> imm;
let Inst{31-28} = Opcode;
let Inst{27-24} = dest;
let Inst{23-20} = src1;
let Inst{19-16} = src2;
let Inst{15-0} = imm;
}
def AddRRI : RRI<"add", 0b0001>;
// I define one of these intrinsics with IntrNoMem and the other
// without it, so that they'll match different top-level DAG opcodes
// (INTRINSIC_WO_CHAIN and INTRINSIC_W_CHAIN), which makes the
// FileCheck-herding easier, because every case I want to detect
// should show up as a separate top-level switch element.
def int_addplus1 : Intrinsic<
[llvm_i32_ty], [llvm_i32_ty, llvm_i32_ty], [IntrNoMem]>;
def int_mul3 : Intrinsic<
[llvm_i32_ty], [llvm_i32_ty, llvm_i32_ty, llvm_i32_ty]>;
def AddPat : Pat<(add i32:$x, i32:$y),
(AddRRI Reg:$x, Reg:$y)>;
def Add1Pat : Pat<(int_addplus1 i32:$x, i32:$y),
(AddRRI Reg:$x, Reg:$y, (i32 1))>;
def SubRRI : RRI<"sub", 0b0010> {
let Pattern = [(set Reg:$dest, (sub Reg:$src1, Reg:$src2))];
}
def MulRRI : RRI<"mul", 0b0011> {
let Pattern = [(set Reg:$dest, (int_mul3 Reg:$src1, Reg:$src2, i32:$imm))];
}
def MulIRR : RRI<"mul2", 0b0100> {
let InOperandList = (ins OptionalIntOperand:$imm, Reg:$src1, Reg:$src2);
}
def MulIRRPat : Pat<(mul i32:$x, i32:$y), (MulIRR Reg:$x, Reg:$y)>;
// ADD: SwitchOpcode{{.*}}TARGET_VAL(ISD::ADD)
// ADD-NEXT: OPC_RecordChild0
// ADD-NEXT: OPC_RecordChild1
// ADD-NEXT: OPC_EmitInteger, MVT::i32, 0
// ADD-NEXT: OPC_MorphNodeTo1, TARGET_VAL(::AddRRI)
// ADDINT: SwitchOpcode{{.*}}TARGET_VAL(ISD::INTRINSIC_WO_CHAIN)
// ADDINT-NEXT: OPC_CheckChild0Integer
// ADDINT-NEXT: OPC_RecordChild1
// ADDINT-NEXT: OPC_RecordChild2
// ADDINT-NEXT: OPC_EmitInteger, MVT::i32, 1
// ADDINT-NEXT: OPC_MorphNodeTo1, TARGET_VAL(::AddRRI)
// SUB: SwitchOpcode{{.*}}TARGET_VAL(ISD::SUB)
// SUB-NEXT: OPC_RecordChild0
// SUB-NEXT: OPC_RecordChild1
// SUB-NEXT: OPC_EmitInteger, MVT::i32, 0
// SUB-NEXT: OPC_MorphNodeTo1, TARGET_VAL(::SubRRI)
// MULINT: SwitchOpcode{{.*}}TARGET_VAL(ISD::INTRINSIC_W_CHAIN)
// MULINT-NEXT: OPC_RecordNode
// MULINT-NEXT: OPC_CheckChild1Integer
// MULINT-NEXT: OPC_RecordChild2
// MULINT-NEXT: OPC_RecordChild3
// MULINT-NEXT: OPC_RecordChild4
// MULINT-NEXT: OPC_EmitMergeInputChains
// MULINT-NEXT: OPC_MorphNodeTo1, TARGET_VAL(::MulRRI)
// MUL: SwitchOpcode{{.*}}TARGET_VAL(ISD::MUL)
// MUL-NEXT: OPC_EmitInteger, MVT::i32, 0
// MUL-NEXT: OPC_RecordChild0
// MUL-NEXT: OPC_RecordChild1
// MUL-NEXT: OPC_MorphNodeTo1, TARGET_VAL(::MulRRI)