//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the James M. Laskey and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
-// This file describes the structures used for instruction itineraries and
-// states. This is used by schedulers to determine instruction states and
-// latencies.
+// This file describes the structures used for instruction
+// itineraries, stages, and operand reads/writes. This is used by
+// schedulers to determine instruction stages and latencies.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TARGET_TARGETINSTRITINERARIES_H
#define LLVM_TARGET_TARGETINSTRITINERARIES_H
+#include <algorithm>
+
namespace llvm {
//===----------------------------------------------------------------------===//
-// Instruction stage - These values represent a step in the execution of an
-// instruction. The latency represents the number of discrete time slots used
-// need to complete the stage. Units represent the choice of functional units
-// that can be used to complete the stage. Eg. IntUnit1, IntUnit2.
-//
+/// 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. A value of -1 indicates that the
+/// next stage should start immediately after the current one.
+/// For example:
+///
+/// { 1, x, -1 }
+/// indicates that the stage occupies FU x for 1 cycle and that
+/// the next stage starts immediately after this one.
+///
+/// { 2, x|y, 1 }
+/// indicates that the stage occupies either FU x or FU y for 2
+/// consecuative cycles and that the next stage starts one cycle
+/// after this stage starts. That is, the stage requirements
+/// overlap in time.
+///
+/// { 1, x, 0 }
+/// indicates that the stage occupies FU x for 1 cycle and that
+/// the next stage starts in this same cycle. This can be used to
+/// indicate that the instruction requires multiple stages at the
+/// same time.
+///
+/// FU reservation can be of two different kinds:
+/// - FUs which instruction actually requires
+/// - FUs which instruction just reserves. Reserved unit is not available for
+/// execution of other instruction. However, several instructions can reserve
+/// the same unit several times.
+/// Such two types of units reservation is used to model instruction domain
+/// change stalls, FUs using the same resource (e.g. same register file), etc.
+
struct InstrStage {
- unsigned Cycles; // Length of stage in machine cycles
- unsigned Units; // Choice of functional units
+ enum ReservationKinds {
+ Required = 0,
+ Reserved = 1
+ };
+
+ unsigned Cycles_; ///< Length of stage in machine cycles
+ unsigned Units_; ///< Choice of functional units
+ int NextCycles_; ///< Number of machine cycles to next stage
+ ReservationKinds Kind_; ///< Kind of the FU reservation
+
+ /// getCycles - returns the number of cycles the stage is occupied
+ unsigned getCycles() const {
+ return Cycles_;
+ }
+
+ /// getUnits - returns the choice of FUs
+ unsigned getUnits() const {
+ return Units_;
+ }
+
+ ReservationKinds getReservationKind() const {
+ return Kind_;
+ }
+
+ /// getNextCycles - returns the number of cycles from the start of
+ /// this stage to the start of the next stage in the itinerary
+ unsigned getNextCycles() const {
+ return (NextCycles_ >= 0) ? (unsigned)NextCycles_ : Cycles_;
+ }
};
//===----------------------------------------------------------------------===//
-// Instruction itinerary - An itinerary represents a sequential series of steps
-// required to complete an instruction. Itineraries are represented as
-// sequences of instruction stages.
-//
+/// Instruction itinerary - An itinerary represents the scheduling
+/// information for an instruction. This includes a set of stages
+/// occupies by the instruction, and the pipeline cycle in which
+/// operands are read and written.
+///
struct InstrItinerary {
- unsigned First; // Index of first stage in itinerary
- unsigned Last; // Index of last + 1 stage in itinerary
+ unsigned FirstStage; ///< Index of first stage in itinerary
+ unsigned LastStage; ///< Index of last + 1 stage in itinerary
+ unsigned FirstOperandCycle; ///< Index of first operand rd/wr
+ unsigned LastOperandCycle; ///< Index of last + 1 operand rd/wr
+};
+
+
+//===----------------------------------------------------------------------===//
+/// Instruction itinerary Data - Itinerary data supplied by a subtarget to be
+/// used by a target.
+///
+class InstrItineraryData {
+public:
+ const InstrStage *Stages; ///< Array of stages selected
+ const unsigned *OperandCycles; ///< Array of operand cycles selected
+ const InstrItinerary *Itineratries; ///< Array of itineraries selected
+
+ /// Ctors.
+ ///
+ InstrItineraryData() : Stages(0), OperandCycles(0), Itineratries(0) {}
+ InstrItineraryData(const InstrStage *S, const unsigned *OS,
+ const InstrItinerary *I)
+ : Stages(S), OperandCycles(OS), Itineratries(I) {}
+
+ /// isEmpty - Returns true if there are no itineraries.
+ ///
+ bool isEmpty() const { return Itineratries == 0; }
+
+ /// isEndMarker - Returns true if the index is for the end marker
+ /// itinerary.
+ ///
+ bool isEndMarker(unsigned ItinClassIndx) const {
+ return ((Itineratries[ItinClassIndx].FirstStage == ~0U) &&
+ (Itineratries[ItinClassIndx].LastStage == ~0U));
+ }
+
+ /// beginStage - Return the first stage of the itinerary.
+ ///
+ const InstrStage *beginStage(unsigned ItinClassIndx) const {
+ unsigned StageIdx = Itineratries[ItinClassIndx].FirstStage;
+ return Stages + StageIdx;
+ }
+
+ /// endStage - Return the last+1 stage of the itinerary.
+ ///
+ const InstrStage *endStage(unsigned ItinClassIndx) const {
+ unsigned StageIdx = Itineratries[ItinClassIndx].LastStage;
+ return Stages + StageIdx;
+ }
+
+ /// getStageLatency - Return the total stage latency of the given
+ /// class. The latency is the maximum completion time for any stage
+ /// in the itinerary.
+ ///
+ unsigned getStageLatency(unsigned ItinClassIndx) const {
+ // If the target doesn't provide itinerary information, use a
+ // simple non-zero default value for all instructions.
+ if (isEmpty())
+ return 1;
+
+ // Calculate the maximum completion time for any stage.
+ unsigned Latency = 0, StartCycle = 0;
+ for (const InstrStage *IS = beginStage(ItinClassIndx),
+ *E = endStage(ItinClassIndx); IS != E; ++IS) {
+ Latency = std::max(Latency, StartCycle + IS->getCycles());
+ StartCycle += IS->getNextCycles();
+ }
+
+ return Latency;
+ }
+
+ /// getOperandCycle - Return the cycle for the given class and
+ /// operand. Return -1 if no cycle is specified for the operand.
+ ///
+ int getOperandCycle(unsigned ItinClassIndx, unsigned OperandIdx) const {
+ if (isEmpty())
+ return -1;
+
+ unsigned FirstIdx = Itineratries[ItinClassIndx].FirstOperandCycle;
+ unsigned LastIdx = Itineratries[ItinClassIndx].LastOperandCycle;
+ if ((FirstIdx + OperandIdx) >= LastIdx)
+ return -1;
+
+ return (int)OperandCycles[FirstIdx + OperandIdx];
+ }
};
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