diff include/llvm/Target/TargetItinerary.td @ 0:95c75e76d11b LLVM3.4

LLVM 3.4
author Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
date Thu, 12 Dec 2013 13:56:28 +0900
parents
children 7d135dc70f03
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/llvm/Target/TargetItinerary.td	Thu Dec 12 13:56:28 2013 +0900
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+//===- TargetItinerary.td - Target Itinierary Description --*- tablegen -*-===//
+//
+//                     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 target-independent scheduling interfaces
+// which should be implemented by each target that uses instruction
+// itineraries for scheduling. Itineraries are details reservation
+// tables for each instruction class. They are most appropriate for
+// in-order machine with complicated scheduling or bundling constraints.
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+// Processor functional unit - These values represent the function units
+// available across all chip sets for the target.  Eg., IntUnit, FPUnit, ...
+// These may be independent values for each chip set or may be shared across
+// all chip sets of the target.  Each functional unit is treated as a resource
+// during scheduling and has an affect instruction order based on availability
+// during a time interval.
+//
+class FuncUnit;
+
+//===----------------------------------------------------------------------===//
+// Pipeline bypass / forwarding - These values specifies the symbolic names of
+// pipeline bypasses which can be used to forward results of instructions
+// that are forwarded to uses.
+class Bypass;
+def NoBypass : Bypass;
+
+class ReservationKind<bits<1> val> {
+  int Value = val;
+}
+
+def Required : ReservationKind<0>;
+def Reserved : ReservationKind<1>;
+
+//===----------------------------------------------------------------------===//
+// Instruction stage - These values represent a non-pipelined step in
+// the execution of an instruction.  Cycles represents the number of
+// discrete time slots needed to complete the stage.  Units represent
+// the choice of functional units that can be used to complete the
+// stage.  Eg. IntUnit1, IntUnit2. NextCycles indicates how many
+// cycles should elapse from the start of this stage to the start of
+// the next stage in the itinerary.  For example:
+//
+// A stage is specified in one of two ways:
+//
+//   InstrStage<1, [FU_x, FU_y]>     - TimeInc defaults to Cycles
+//   InstrStage<1, [FU_x, FU_y], 0>  - TimeInc explicit
+//
+
+class InstrStage<int cycles, list<FuncUnit> units,
+                 int timeinc = -1,
+                 ReservationKind kind = Required> {
+  int Cycles          = cycles;       // length of stage in machine cycles
+  list<FuncUnit> Units = units;       // choice of functional units
+  int TimeInc         = timeinc;      // cycles till start of next stage
+  int Kind            = kind.Value;   // kind of FU reservation
+}
+
+//===----------------------------------------------------------------------===//
+// Instruction itinerary - An itinerary represents a sequential series of steps
+// required to complete an instruction.  Itineraries are represented as lists of
+// instruction stages.
+//
+
+//===----------------------------------------------------------------------===//
+// Instruction itinerary classes - These values represent 'named' instruction
+// itinerary.  Using named itineraries simplifies managing groups of
+// instructions across chip sets.  An instruction uses the same itinerary class
+// across all chip sets.  Thus a new chip set can be added without modifying
+// instruction information.
+//
+class InstrItinClass;
+def NoItinerary : InstrItinClass;
+
+//===----------------------------------------------------------------------===//
+// Instruction itinerary data - These values provide a runtime map of an
+// instruction itinerary class (name) to its itinerary data.
+//
+// NumMicroOps represents the number of micro-operations that each instruction
+// in the class are decoded to. If the number is zero, then it means the
+// instruction can decode into variable number of micro-ops and it must be
+// determined dynamically. This directly relates to the itineraries
+// global IssueWidth property, which constrains the number of microops
+// that can issue per cycle.
+//
+// OperandCycles are optional "cycle counts". They specify the cycle after
+// instruction issue the values which correspond to specific operand indices
+// are defined or read. Bypasses are optional "pipeline forwarding pathes", if
+// a def by an instruction is available on a specific bypass and the use can
+// read from the same bypass, then the operand use latency is reduced by one.
+//
+//  InstrItinData<IIC_iLoad_i , [InstrStage<1, [A9_Pipe1]>,
+//                               InstrStage<1, [A9_AGU]>],
+//                              [3, 1], [A9_LdBypass]>,
+//  InstrItinData<IIC_iMVNr   , [InstrStage<1, [A9_Pipe0, A9_Pipe1]>],
+//                              [1, 1], [NoBypass, A9_LdBypass]>,
+//
+// In this example, the instruction of IIC_iLoadi reads its input on cycle 1
+// (after issue) and the result of the load is available on cycle 3. The result
+// is available via forwarding path A9_LdBypass. If it's used by the first
+// source operand of instructions of IIC_iMVNr class, then the operand latency
+// is reduced by 1.
+class InstrItinData<InstrItinClass Class, list<InstrStage> stages,
+                    list<int> operandcycles = [],
+                    list<Bypass> bypasses = [], int uops = 1> {
+  InstrItinClass TheClass = Class;
+  int NumMicroOps = uops;
+  list<InstrStage> Stages = stages;
+  list<int> OperandCycles = operandcycles;
+  list<Bypass> Bypasses = bypasses;
+}
+
+//===----------------------------------------------------------------------===//
+// Processor itineraries - These values represent the set of all itinerary
+// classes for a given chip set.
+//
+// Set property values to -1 to use the default.
+// See InstrItineraryProps for comments and defaults.
+class ProcessorItineraries<list<FuncUnit> fu, list<Bypass> bp,
+                           list<InstrItinData> iid> {
+  list<FuncUnit> FU = fu;
+  list<Bypass> BP = bp;
+  list<InstrItinData> IID = iid;
+}
+
+// NoItineraries - A marker that can be used by processors without schedule
+// info. Subtargets using NoItineraries can bypass the scheduler's
+// expensive HazardRecognizer because no reservation table is needed.
+def NoItineraries : ProcessorItineraries<[], [], []>;