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IfConverter: Use TargetSchedule for instruction latencies

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For targets that have instruction itineraries this means no change. Targets
that move over to the new schedule model will use be able the new schedule
module for instruction latencies in the if-converter (the logic is such that if
there is no itineary we will use the new sched model for the latencies).

Before, we queried "TTI->getInstructionLatency()" for the instruction latency
and the extra prediction cost. Now, we query the TargetSchedule abstraction for
the instruction latency and TargetInstrInfo for the extra predictation cost. The
TargetSchedule abstraction will internally call "TTI->getInstructionLatency" if
an itinerary exists, otherwise it will use the new schedule model.

ATTENTION: Out of tree targets!

(I will also send out an email later to LLVMDev)

This means, if your target implements

 unsigned getInstrLatency(const InstrItineraryData *ItinData,
                          const MachineInstr *MI,
                          unsigned *PredCost);

and returns a value for "PredCost", you now also need to implement

 unsigned getPredictationCost(const MachineInstr *MI);

(if your target uses the IfConversion.cpp pass)

radar://15077010

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191671 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Arnold Schwaighofer
2013-09-30 15:28:56 +00:00
parent a5b9cd1c68
commit d42730dc71
9 changed files with 57 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
lib/CodeGen/IfConversion.cpp
View File

@ -22,6 +22,7 @@
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetSchedule.h"
#include "llvm/MC/MCInstrItineraries.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
@ -31,6 +32,8 @@
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetSubtargetInfo.h"
using namespace llvm;
// Hidden options for help debugging.
@ -150,11 +153,11 @@ namespace {
/// BBAnalysis - Results of if-conversion feasibility analysis indexed by
/// basic block number.
std::vector<BBInfo> BBAnalysis;
TargetSchedModel SchedModel;
const TargetLoweringBase *TLI;
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
const InstrItineraryData *InstrItins;
const MachineBranchProbabilityInfo *MBPI;
MachineRegisterInfo *MRI;
@ -267,7 +270,11 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
TRI = MF.getTarget().getRegisterInfo();
MBPI = &getAnalysis<MachineBranchProbabilityInfo>();
MRI = &MF.getRegInfo();
InstrItins = MF.getTarget().getInstrItineraryData();
const TargetSubtargetInfo &ST =
MF.getTarget().getSubtarget<TargetSubtargetInfo>();
SchedModel.init(*ST.getSchedModel(), &ST, TII);
if (!TII) return false;
PreRegAlloc = MRI->isSSA();
@ -672,9 +679,8 @@ void IfConverter::ScanInstructions(BBInfo &BBI) {
if (!isPredicated) {
BBI.NonPredSize++;
unsigned ExtraPredCost = 0;
unsigned NumCycles = TII->getInstrLatency(InstrItins, &*I,
&ExtraPredCost);
unsigned ExtraPredCost = TII->getPredicationCost(&*I);
unsigned NumCycles = SchedModel.computeInstrLatency(&*I, false);
if (NumCycles > 1)
BBI.ExtraCost += NumCycles-1;
BBI.ExtraCost2 += ExtraPredCost;
@ -1511,8 +1517,8 @@ void IfConverter::CopyAndPredicateBlock(BBInfo &ToBBI, BBInfo &FromBBI,
MachineInstr *MI = MF.CloneMachineInstr(I);
ToBBI.BB->insert(ToBBI.BB->end(), MI);
ToBBI.NonPredSize++;
unsigned ExtraPredCost = 0;
unsigned NumCycles = TII->getInstrLatency(InstrItins, &*I, &ExtraPredCost);
unsigned ExtraPredCost = TII->getPredicationCost(&*I);
unsigned NumCycles = SchedModel.computeInstrLatency(&*I, false);
if (NumCycles > 1)
ToBBI.ExtraCost += NumCycles-1;
ToBBI.ExtraCost2 += ExtraPredCost;