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Fix some subtle bugs: bug during succeessor copying; incorrectly updating states of ifcvted blocks. 

llvm-svn: 37429
This commit is contained in:
Evan Cheng 2007-06-05 00:07:37 +00:00
parent 6357bf20fa
commit 17aad8164e
1 changed files with 19 additions and 20 deletions
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39
llvm/lib/CodeGen/IfConversion.cpp
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@ -153,7 +153,9 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
default: assert(false && "Unexpected!"); default: assert(false && "Unexpected!");
break; break;
case ICReAnalyze: case ICReAnalyze:
// One or more of 'childrean' have been modified, abort! // One or more of 'children' have been modified, abort!
case ICDead:
// Block has been already been if-converted, abort!
break; break;
case ICSimple: case ICSimple:
case ICSimpleFalse: case ICSimpleFalse:
@ -219,9 +221,10 @@ bool IfConverter::ReverseBranchCondition(BBInfo &BBI) {
void IfConverter::StructuralAnalysis(MachineBasicBlock *BB) { void IfConverter::StructuralAnalysis(MachineBasicBlock *BB) {
BBInfo &BBI = BBAnalysis[BB->getNumber()]; BBInfo &BBI = BBAnalysis[BB->getNumber()];
if (BBI.Kind == ICReAnalyze) if (BBI.Kind == ICReAnalyze) {
BBI.BrCond.clear(); BBI.BrCond.clear();
else { BBI.TrueBB = BBI.FalseBB = NULL;
} else {
if (BBI.Kind != ICNotAnalyzed) if (BBI.Kind != ICNotAnalyzed)
return; // Already analyzed. return; // Already analyzed.
BBI.BB = BB; BBI.BB = BB;
@ -504,10 +507,7 @@ bool IfConverter::IfConvertSimple(BBInfo &BBI) {
std::copy(Cond.begin(), Cond.end(), std::back_inserter(BBI.Predicate)); std::copy(Cond.begin(), Cond.end(), std::back_inserter(BBI.Predicate));
// Update block info. BB can be iteratively if-converted. // Update block info. BB can be iteratively if-converted.
BBI.Kind = ICNotAnalyzed; BBI.Kind = ICReAnalyze;
BBI.TrueBB = BBI.FalseBB = NULL;
BBI.BrCond.clear();
TII->AnalyzeBranch(*BBI.BB, BBI.TrueBB, BBI.FalseBB, BBI.BrCond);
ReTryPreds(BBI.BB); ReTryPreds(BBI.BB);
CvtBBI->Kind = ICDead; CvtBBI->Kind = ICDead;
@ -537,9 +537,11 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI) {
// Join the 'true' and 'false' blocks if the 'false' block has no other // Join the 'true' and 'false' blocks if the 'false' block has no other
// predecessors. Otherwise, add a unconditional branch from 'true' to 'false'. // predecessors. Otherwise, add a unconditional branch from 'true' to 'false'.
BBInfo &FalseBBI = BBAnalysis[BBI.FalseBB->getNumber()]; BBInfo &FalseBBI = BBAnalysis[BBI.FalseBB->getNumber()];
if (FalseBBI.BB->pred_size() == 2) bool FalseBBDead = false;
if (FalseBBI.BB->pred_size() == 2) {
MergeBlocks(TrueBBI, FalseBBI); MergeBlocks(TrueBBI, FalseBBI);
else if (!isNextBlock(TrueBBI.BB, FalseBBI.BB)) FalseBBDead = true;
} else if (!isNextBlock(TrueBBI.BB, FalseBBI.BB))
InsertUncondBranch(TrueBBI.BB, FalseBBI.BB, TII); InsertUncondBranch(TrueBBI.BB, FalseBBI.BB, TII);
// Now merge the entry of the triangle with the true block. // Now merge the entry of the triangle with the true block.
@ -549,12 +551,11 @@ bool IfConverter::IfConvertTriangle(BBInfo &BBI) {
std::back_inserter(BBI.Predicate)); std::back_inserter(BBI.Predicate));
// Update block info. BB can be iteratively if-converted. // Update block info. BB can be iteratively if-converted.
BBI.Kind = ICNotClassfied; BBI.Kind = ICReAnalyze;
BBI.TrueBB = BBI.FalseBB = NULL;
BBI.BrCond.clear();
TII->AnalyzeBranch(*BBI.BB, BBI.TrueBB, BBI.FalseBB, BBI.BrCond);
ReTryPreds(BBI.BB); ReTryPreds(BBI.BB);
TrueBBI.Kind = ICDead; TrueBBI.Kind = ICDead;
if (FalseBBDead)
FalseBBI.Kind = ICDead;
// FIXME: Must maintain LiveIns. // FIXME: Must maintain LiveIns.
return true; return true;
@ -683,10 +684,7 @@ bool IfConverter::IfConvertDiamond(BBInfo &BBI) {
// Update block info. BB may be iteratively if-converted. // Update block info. BB may be iteratively if-converted.
if (OkToIfcvt) { if (OkToIfcvt) {
BBI.Kind = ICNotClassfied; BBI.Kind = ICReAnalyze;
BBI.TrueBB = BBI.FalseBB = NULL;
BBI.BrCond.clear();
TII->AnalyzeBranch(*BBI.BB, BBI.TrueBB, BBI.FalseBB, BBI.BrCond);
ReTryPreds(BBI.BB); ReTryPreds(BBI.BB);
} }
TrueBBI.Kind = ICDead; TrueBBI.Kind = ICDead;
@ -734,9 +732,10 @@ static void TransferPreds(MachineBasicBlock *ToBB, MachineBasicBlock *FromBB) {
static void TransferSuccs(MachineBasicBlock *ToBB, MachineBasicBlock *FromBB) { static void TransferSuccs(MachineBasicBlock *ToBB, MachineBasicBlock *FromBB) {
for (MachineBasicBlock::succ_iterator I = FromBB->succ_begin(), for (MachineBasicBlock::succ_iterator I = FromBB->succ_begin(),
E = FromBB->succ_end(); I != E; ++I) { E = FromBB->succ_end(); I != E; ++I) {
FromBB->removeSuccessor(*I); MachineBasicBlock *Succ = *I;
if (!ToBB->isSuccessor(*I)) FromBB->removeSuccessor(Succ);
ToBB->addSuccessor(*I); if (!ToBB->isSuccessor(Succ))
ToBB->addSuccessor(Succ);
} }
} }