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(NFC)[MachineCombiner] Improve debug output.

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llvm-svn: 325217
This commit is contained in:
Andrew V. Tischenko 2018-02-15 07:55:02 +00:00
parent 2fec5b71da
commit 196eec0104
1 changed files with 53 additions and 28 deletions
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81
lib/CodeGen/MachineCombiner.cpp
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@ -39,6 +39,10 @@ inc_threshold("machine-combiner-inc-threshold", cl::Hidden,
cl::desc("Incremental depth computation will be used for basic "
"blocks with more instructions."), cl::init(500));
static cl::opt<bool> dump_intrs("machine-combiner-dump-subst-intrs", cl::Hidden,
cl::desc("Dump all substituted intrs"),
cl::init(false));
#ifdef EXPENSIVE_CHECKS
static cl::opt<bool> VerifyPatternOrder(
"machine-combiner-verify-pattern-order", cl::Hidden,
@ -55,6 +59,7 @@ static cl::opt<bool> VerifyPatternOrder(
namespace {
class MachineCombiner : public MachineFunctionPass {
const TargetSubtargetInfo *STI;
const TargetInstrInfo *TII;
const TargetRegisterInfo *TRI;
MCSchedModel SchedModel;
@ -162,9 +167,6 @@ MachineCombiner::getDepth(SmallVectorImpl<MachineInstr *> &InsInstrs,
// are tracked in the InstrIdxForVirtReg map depth is looked up in InstrDepth
for (auto *InstrPtr : InsInstrs) { // for each Use
unsigned IDepth = 0;
DEBUG(dbgs() << "NEW INSTR ";
InstrPtr->print(dbgs(), TII);
dbgs() << "\n";);
for (const MachineOperand &MO : InstrPtr->operands()) {
// Check for virtual register operand.
if (!(MO.isReg() && TargetRegisterInfo::isVirtualRegister(MO.getReg())))
@ -306,17 +308,20 @@ bool MachineCombiner::improvesCriticalPathLen(
unsigned NewRootDepth = getDepth(InsInstrs, InstrIdxForVirtReg, BlockTrace);
unsigned RootDepth = BlockTrace.getInstrCycles(*Root).Depth;
DEBUG(dbgs() << "DEPENDENCE DATA FOR " << *Root << "\n";
dbgs() << " NewRootDepth: " << NewRootDepth << "\n";
dbgs() << " RootDepth: " << RootDepth << "\n");
DEBUG(dbgs() << " Dependence data for " << *Root << "\tNewRootDepth: "
<< NewRootDepth << "\tRootDepth: " << RootDepth);
// For a transform such as reassociation, the cost equation is
// conservatively calculated so that we must improve the depth (data
// dependency cycles) in the critical path to proceed with the transform.
// Being conservative also protects against inaccuracies in the underlying
// machine trace metrics and CPU models.
if (getCombinerObjective(Pattern) == CombinerObjective::MustReduceDepth)
if (getCombinerObjective(Pattern) == CombinerObjective::MustReduceDepth) {
DEBUG(dbgs() << "\tIt MustReduceDepth ");
DEBUG(NewRootDepth < RootDepth ? dbgs() << "\t and it does it\n"
: dbgs() << "\t but it does NOT do it\n");
return NewRootDepth < RootDepth;
}
// A more flexible cost calculation for the critical path includes the slack
// of the original code sequence. This may allow the transform to proceed
@ -329,17 +334,19 @@ bool MachineCombiner::improvesCriticalPathLen(
unsigned RootSlack = BlockTrace.getInstrSlack(*Root);
unsigned NewCycleCount = NewRootDepth + NewRootLatency;
unsigned OldCycleCount = RootDepth + RootLatency +
(SlackIsAccurate ? RootSlack : 0);
DEBUG(dbgs() << " NewRootLatency: " << NewRootLatency << "\n";
dbgs() << " RootLatency: " << RootLatency << "\n";
dbgs() << " RootSlack: " << RootSlack << " SlackIsAccurate="
<< SlackIsAccurate << "\n";
dbgs() << " NewRootDepth + NewRootLatency = "
<< NewCycleCount << "\n";
dbgs() << " RootDepth + RootLatency + RootSlack = "
<< OldCycleCount << "\n";
);
unsigned OldCycleCount =
RootDepth + RootLatency + (SlackIsAccurate ? RootSlack : 0);
DEBUG(dbgs() << "\n\tNewRootLatency: " << NewRootLatency << "\tRootLatency: "
<< RootLatency << "\n\tRootSlack: " << RootSlack
<< " SlackIsAccurate=" << SlackIsAccurate
<< "\n\tNewRootDepth + NewRootLatency = " << NewCycleCount
<< "\n\tRootDepth + RootLatency + RootSlack = "
<< OldCycleCount;);
DEBUG(NewCycleCount <= OldCycleCount
? dbgs() << "\n\t It IMPROVES PathLen because"
: dbgs() << "\n\t It DOES NOT improve PathLen because");
DEBUG(dbgs() << "\n\t\tNewCycleCount = " << NewCycleCount
<< ", OldCycleCount = " << OldCycleCount << "\n");
return NewCycleCount <= OldCycleCount;
}
@ -385,9 +392,14 @@ bool MachineCombiner::preservesResourceLen(
unsigned ResLenAfterCombine =
BlockTrace.getResourceLength(MBBarr, MSCInsArr, MSCDelArr);
DEBUG(dbgs() << "RESOURCE DATA: \n";
dbgs() << " resource len before: " << ResLenBeforeCombine
<< " after: " << ResLenAfterCombine << "\n";);
DEBUG(dbgs() << "\t\tResource length before replacement: "
<< ResLenBeforeCombine << " and after: " << ResLenAfterCombine
<< "\n";);
DEBUG(
ResLenAfterCombine <= ResLenBeforeCombine
? dbgs() << "\t\t As result it IMPROVES/PRESERVES Resource Length\n"
: dbgs() << "\t\t As result it DOES NOT improve/preserve Resource "
"Length\n");
return ResLenAfterCombine <= ResLenBeforeCombine;
}
@ -495,8 +507,6 @@ bool MachineCombiner::combineInstructions(MachineBasicBlock *MBB) {
while (BlockIter != MBB->end()) {
auto &MI = *BlockIter++;
DEBUG(dbgs() << "INSTR "; MI.dump(); dbgs() << "\n";);
SmallVector<MachineCombinerPattern, 16> Patterns;
// The motivating example is:
//
@ -545,6 +555,21 @@ bool MachineCombiner::combineInstructions(MachineBasicBlock *MBB) {
if (!NewInstCount)
continue;
DEBUG(if (dump_intrs) {
dbgs() << "\tFor the Pattern (" << (int)P << ") these instructions could be removed\n";
for (auto const *InstrPtr : DelInstrs) {
dbgs() << "\t\t" << STI->getSchedInfoStr(*InstrPtr) << ": ";
InstrPtr->print(dbgs(), false, false, TII);
dbgs() << "\n";
}
dbgs() << "\tThese instructions could replace the removed ones\n";
for (auto const *InstrPtr : InsInstrs) {
dbgs() << "\t\t" << STI->getSchedInfoStr(*InstrPtr) << ": ";
InstrPtr->print(dbgs(), false, false, TII);
dbgs() << "\n";
}
});
bool SubstituteAlways = false;
if (ML && TII->isThroughputPattern(P))
SubstituteAlways = true;
@ -606,11 +631,11 @@ bool MachineCombiner::combineInstructions(MachineBasicBlock *MBB) {
}
bool MachineCombiner::runOnMachineFunction(MachineFunction &MF) {
const TargetSubtargetInfo &STI = MF.getSubtarget();
TII = STI.getInstrInfo();
TRI = STI.getRegisterInfo();
SchedModel = STI.getSchedModel();
TSchedModel.init(SchedModel, &STI, TII);
STI = &MF.getSubtarget();
TII = STI->getInstrInfo();
TRI = STI->getRegisterInfo();
SchedModel = STI->getSchedModel();
TSchedModel.init(SchedModel, STI, TII);
MRI = &MF.getRegInfo();
MLI = &getAnalysis<MachineLoopInfo>();
Traces = &getAnalysis<MachineTraceMetrics>();