llvm-6502/include/llvm/CodeGen/PostRAHazardRecognizer.h
Evan Cheng 3ef1c8759a Teach if-converter to be more careful with predicating instructions that would
take multiple cycles to decode.
For the current if-converter clients (actually only ARM), the instructions that
are predicated on false are not nops. They would still take machine cycles to
decode. Micro-coded instructions such as LDM / STM can potentially take multiple
cycles to decode. If-converter should take treat them as non-micro-coded
simple instructions.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113570 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-10 01:29:16 +00:00

95 lines
2.5 KiB
C++

//=- llvm/CodeGen/PostRAHazardRecognizer.h - Scheduling Support -*- C++ -*-=//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the PostRAHazardRecognizer class, which
// implements hazard-avoidance heuristics for scheduling, based on the
// scheduling itineraries specified for the target.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_EXACTHAZARDRECOGNIZER_H
#define LLVM_CODEGEN_EXACTHAZARDRECOGNIZER_H
#include "llvm/CodeGen/ScheduleHazardRecognizer.h"
#include "llvm/System/DataTypes.h"
#include <cassert>
#include <cstring>
#include <string>
namespace llvm {
class InstrItineraryData;
class SUnit;
class PostRAHazardRecognizer : public ScheduleHazardRecognizer {
// ScoreBoard to track function unit usage. ScoreBoard[0] is a
// mask of the FUs in use in the cycle currently being
// schedule. ScoreBoard[1] is a mask for the next cycle. The
// ScoreBoard is used as a circular buffer with the current cycle
// indicated by Head.
class ScoreBoard {
unsigned *Data;
// The maximum number of cycles monitored by the Scoreboard. This
// value is determined based on the target itineraries to ensure
// that all hazards can be tracked.
size_t Depth;
// Indices into the Scoreboard that represent the current cycle.
size_t Head;
public:
ScoreBoard():Data(NULL), Depth(0), Head(0) { }
~ScoreBoard() {
delete[] Data;
}
size_t getDepth() const { return Depth; }
unsigned& operator[](size_t idx) const {
assert(Depth && "ScoreBoard was not initialized properly!");
return Data[(Head + idx) % Depth];
}
void reset(size_t d = 1) {
if (Data == NULL) {
Depth = d;
Data = new unsigned[Depth];
}
memset(Data, 0, Depth * sizeof(Data[0]));
Head = 0;
}
void advance() {
Head = (Head + 1) % Depth;
}
// Print the scoreboard.
void dump() const;
};
// Itinerary data for the target.
const InstrItineraryData *ItinData;
ScoreBoard ReservedScoreboard;
ScoreBoard RequiredScoreboard;
public:
PostRAHazardRecognizer(const InstrItineraryData *ItinData);
virtual HazardType getHazardType(SUnit *SU);
virtual void Reset();
virtual void EmitInstruction(SUnit *SU);
virtual void AdvanceCycle();
};
}
#endif