mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-17 05:29:24 +00:00
Split loops and do CFG cleanup.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41029 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Devang Patel
parent
9626a9c700
commit
98147a306e
@ -97,6 +97,9 @@ namespace {
|
||||
/// loop may not be eliminated.
|
||||
bool safeExitBlock(SplitInfo &SD, BasicBlock *BB);
|
||||
|
||||
/// removeBlocks - Remove basic block BB and all blocks dominated by BB.
|
||||
void removeBlocks(BasicBlock *InBB);
|
||||
|
||||
/// Find cost of spliting loop L.
|
||||
unsigned findSplitCost(Loop *L, SplitInfo &SD);
|
||||
bool splitLoop(SplitInfo &SD);
|
||||
@ -105,7 +108,9 @@ namespace {
|
||||
IndVar = NULL;
|
||||
IndVarIncrement = NULL;
|
||||
ExitCondition = NULL;
|
||||
StartValue = ExitValue = NULL;
|
||||
StartValue = NULL;
|
||||
ExitValueNum = 0;
|
||||
SplitData.clear();
|
||||
}
|
||||
|
||||
private:
|
||||
@ -128,8 +133,8 @@ namespace {
|
||||
// Induction variable's initial value.
|
||||
Value *StartValue;
|
||||
|
||||
// Induction variable's final loop exit value.
|
||||
Value *ExitValue;
|
||||
// Induction variable's final loop exit value operand number in exit condition..
|
||||
unsigned ExitValueNum;
|
||||
};
|
||||
|
||||
char LoopIndexSplit::ID = 0;
|
||||
@ -285,15 +290,15 @@ void LoopIndexSplit::findLoopConditionals() {
|
||||
SCEVHandle SH1 = SE->getSCEV(V1);
|
||||
|
||||
if (SH0->isLoopInvariant(L) && isa<SCEVAddRecExpr>(SH1)) {
|
||||
ExitValue = V0;
|
||||
ExitValueNum = 0;
|
||||
findIndVar(V1, L);
|
||||
}
|
||||
else if (SH1->isLoopInvariant(L) && isa<SCEVAddRecExpr>(SH0)) {
|
||||
ExitValue = V1;
|
||||
ExitValueNum = 1;
|
||||
findIndVar(V0, L);
|
||||
}
|
||||
|
||||
if (!ExitValue || !IndVar)
|
||||
if (!IndVar)
|
||||
ExitCondition = NULL;
|
||||
else if (IndVar) {
|
||||
BasicBlock *Preheader = L->getLoopPreheader();
|
||||
@ -430,7 +435,8 @@ bool LoopIndexSplit::processOneIterationLoop(SplitInfo &SD) {
|
||||
Terminator);
|
||||
Instruction *C2 = new ICmpInst(SignedPredicate ?
|
||||
ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT,
|
||||
SD.SplitValue, ExitValue, "lisplit",
|
||||
SD.SplitValue,
|
||||
ExitCondition->getOperand(ExitValueNum), "lisplit",
|
||||
Terminator);
|
||||
Instruction *NSplitCond = BinaryOperator::createAnd(C1, C2, "lisplit",
|
||||
Terminator);
|
||||
@ -580,6 +586,45 @@ unsigned LoopIndexSplit::findSplitCost(Loop *L, SplitInfo &SD) {
|
||||
return Cost;
|
||||
}
|
||||
|
||||
/// removeBlocks - Remove basic block BB and all blocks dominated by BB.
|
||||
void LoopIndexSplit::removeBlocks(BasicBlock *InBB) {
|
||||
|
||||
SmallVector<BasicBlock *, 8> WorkList;
|
||||
WorkList.push_back(InBB);
|
||||
while (!WorkList.empty()) {
|
||||
BasicBlock *BB = WorkList.back(); WorkList.pop_back();
|
||||
|
||||
// First process all successor
|
||||
for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI) {
|
||||
BasicBlock *SuccBB = *SI;
|
||||
if (DT->dominates(BB, SuccBB)) {
|
||||
WorkList.push_back(SuccBB);
|
||||
continue;
|
||||
}
|
||||
|
||||
// If SuccBB is not dominated by BB then it is not removed, however remove
|
||||
// any PHI incoming edge from BB.
|
||||
for(BasicBlock::iterator SBI = SuccBB->begin(), SBE = SuccBB->end();
|
||||
SBI != SBE; ++SBI) {
|
||||
if (PHINode *PN = dyn_cast<PHINode>(SBI))
|
||||
PN->removeIncomingValue(BB);
|
||||
else
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
// Now delete BB;
|
||||
for(BasicBlock::iterator BBI = BB->begin(), BBE = BB->end();
|
||||
BBI != BBE; ++BBI) {
|
||||
Instruction *I = BBI;
|
||||
I->replaceAllUsesWith(UndefValue::get(I->getType()));
|
||||
I->eraseFromParent();
|
||||
}
|
||||
LI->removeBlock(BB);
|
||||
BB->eraseFromParent();
|
||||
}
|
||||
}
|
||||
|
||||
bool LoopIndexSplit::splitLoop(SplitInfo &SD) {
|
||||
|
||||
BasicBlock *Preheader = L->getLoopPreheader();
|
||||
@ -600,9 +645,12 @@ bool LoopIndexSplit::splitLoop(SplitInfo &SD) {
|
||||
else {
|
||||
Value *C1 = new ICmpInst(SignedPredicate ?
|
||||
ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT,
|
||||
SD.SplitValue, ExitValue, "lsplit.ev",
|
||||
SD.SplitValue,
|
||||
ExitCondition->getOperand(ExitValueNum),
|
||||
"lsplit.ev",
|
||||
Preheader->getTerminator());
|
||||
TLExitValue = new SelectInst(C1, SD.SplitValue, ExitValue,
|
||||
TLExitValue = new SelectInst(C1, SD.SplitValue,
|
||||
ExitCondition->getOperand(ExitValueNum),
|
||||
"lsplit.ev", Preheader->getTerminator());
|
||||
|
||||
Value *C2 = new ICmpInst(SignedPredicate ?
|
||||
@ -613,28 +661,62 @@ bool LoopIndexSplit::splitLoop(SplitInfo &SD) {
|
||||
"lsplit.sv", Preheader->getTerminator());
|
||||
}
|
||||
|
||||
//[*] Split Exit Edge.
|
||||
//[*] Clone loop. Avoid true destination of split condition and
|
||||
// the blocks dominated by true destination.
|
||||
DenseMap<const Value *, Value *> ValueMap;
|
||||
Loop *FalseLoop = CloneLoop(L, LPM, LI, ValueMap, this);
|
||||
BasicBlock *FalseHeader = FalseLoop->getHeader();
|
||||
|
||||
//[*] True loop's exit edge enters False loop.
|
||||
PHINode *IndVarClone = cast<PHINode>(ValueMap[IndVar]);
|
||||
BasicBlock *ExitBlock = ExitCondition->getParent();
|
||||
BranchInst *ExitInsn = dyn_cast<BranchInst>(ExitBlock->getTerminator());
|
||||
assert (ExitInsn && "Unable to find suitable loop exit branch");
|
||||
BasicBlock *ExitDest = ExitInsn->getSuccessor(1);
|
||||
if (L->contains(ExitDest))
|
||||
|
||||
for (BasicBlock::iterator BI = FalseHeader->begin(), BE = FalseHeader->end();
|
||||
BI != BE; ++BI) {
|
||||
if (PHINode *PN = dyn_cast<PHINode>(BI)) {
|
||||
PN->removeIncomingValue(Preheader);
|
||||
if (PN == IndVarClone)
|
||||
PN->addIncoming(FLStartValue, ExitBlock);
|
||||
// else { FIXME : Handl last value assignments.}
|
||||
}
|
||||
else
|
||||
break;
|
||||
}
|
||||
|
||||
if (L->contains(ExitDest)) {
|
||||
ExitDest = ExitInsn->getSuccessor(0);
|
||||
ExitInsn->setSuccessor(0, FalseHeader);
|
||||
} else
|
||||
ExitInsn->setSuccessor(1, FalseHeader);
|
||||
|
||||
assert (!L->contains(ExitDest) && " Unable to find exit edge destination");
|
||||
SplitEdge(ExitBlock, ExitDest, this);
|
||||
|
||||
//[*] Clone loop. Avoid true destination of split condition and
|
||||
// the blocks dominated by true destination.
|
||||
DenseMap<const Value *, Value *> ValueMap;
|
||||
CloneLoop(L, LPM, LI, ValueMap, this);
|
||||
//[*] Split Exit Edge.
|
||||
SplitEdge(ExitBlock, FalseHeader, this);
|
||||
|
||||
//[*] True loops exit edge enters False loop.
|
||||
//[*] Eliminate split condition's false branch from True loop.
|
||||
// Update true loop dom info.
|
||||
//[*] Update True loop's exit value using NewExitValue.
|
||||
//[*] Update False loop's start value using NewStartValue.
|
||||
//[*] Fix lack of true branch in False loop CFG.
|
||||
// Update false loop dom info.
|
||||
//[*] Update dom info in general.
|
||||
return false;
|
||||
// Update true loop dom info (FIXME).
|
||||
BasicBlock *SplitBlock = SD.SplitCondition->getParent();
|
||||
BranchInst *BR = cast<BranchInst>(SplitBlock->getTerminator());
|
||||
BasicBlock *FBB = BR->getSuccessor(1);
|
||||
BR->setUnconditionalDest(BR->getSuccessor(0));
|
||||
removeBlocks(FBB);
|
||||
|
||||
//[*] Update True loop's exit value using new exit value.
|
||||
ExitCondition->setOperand(ExitValueNum, TLExitValue);
|
||||
|
||||
//[*] Eliminate split condition's true branch in False loop CFG.
|
||||
// Update false loop dom info (FXME).
|
||||
BasicBlock *FSplitBlock = cast<BasicBlock>(ValueMap[SplitBlock]);
|
||||
BranchInst *FBR = cast<BranchInst>(FSplitBlock->getTerminator());
|
||||
BasicBlock *TBB = FBR->getSuccessor(0);
|
||||
FBR->setUnconditionalDest(FBR->getSuccessor(1));
|
||||
removeBlocks(TBB);
|
||||
|
||||
//[*] Update dom info in general (FIXME).
|
||||
return true;
|
||||
}
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user