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Correctly mark early-exit on the false path.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37387 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2007-06-01 20:29:21 +00:00
parent 8e21fb7df8
commit b5a0690788
1 changed files with 9 additions and 8 deletions
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17
lib/CodeGen/IfConversion.cpp
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@ -33,6 +33,7 @@ namespace {
ICReAnalyze, // BB must be re-analyzed.
ICNotClassfied, // BB data valid, but not classified.
ICEarlyExit, // BB is entry of an early-exit sub-CFG.
ICEarlyExitFalse,// Same as ICEarlyExit, but on the false path.
ICTriangle, // BB is entry of a triangle sub-CFG.
ICDiamond, // BB is entry of a diamond sub-CFG.
ICChild, // BB is part of the sub-CFG that'll be predicated.
@ -151,6 +152,7 @@ bool IfConverter::runOnMachineFunction(MachineFunction &MF) {
// One or more of 'childrean' have been modified, abort!
break;
case ICEarlyExit:
case ICEarlyExitFalse:
DOUT << "Ifcvt (Early exit): BB#" << BBI.BB->getNumber() << "\n";
Change |= IfConvertEarlyExit(BBI);
break;
@ -239,7 +241,7 @@ void IfConverter::StructuralAnalysis(MachineBasicBlock *BB) {
TrueBBI.Kind = ICChild;
} else if (!(TrueBBI.hasEarlyExit && TrueNumPreds <= 1) &&
(FalseBBI.hasEarlyExit && FalseNumPreds <=1)) {
BBI.Kind = ICEarlyExit;
BBI.Kind = ICEarlyExitFalse;
FalseBBI.Kind = ICChild;
} else if (TrueBBI.TrueBB && TrueBBI.TrueBB == BBI.FalseBB) {
// Triangle:
@ -335,6 +337,7 @@ bool IfConverter::AnalyzeBlocks(MachineFunction &MF,
BBInfo &BBI = BBAnalysis[BB->getNumber()];
switch (BBI.Kind) {
case ICEarlyExit:
case ICEarlyExitFalse:
case ICTriangle:
case ICDiamond:
Candidates.push_back(&BBI);
@ -406,6 +409,8 @@ static void InsertUncondBranch(MachineBasicBlock *BB, MachineBasicBlock *ToBB,
/// IfConvertEarlyExit - If convert a early exit sub-CFG.
///
bool IfConverter::IfConvertEarlyExit(BBInfo &BBI) {
bool ReverseCond = BBI.Kind == ICEarlyExitFalse;
BBI.Kind = ICNotClassfied;
BBInfo &TrueBBI = BBAnalysis[BBI.TrueBB->getNumber()];
@ -413,15 +418,11 @@ bool IfConverter::IfConvertEarlyExit(BBInfo &BBI) {
BBInfo *CvtBBI = &TrueBBI;
BBInfo *NextBBI = &FalseBBI;
bool ReserveCond = false;
if (TrueBBI.Kind != ICChild) {
std::swap(CvtBBI, NextBBI);
ReserveCond = true;
}
std::vector<MachineOperand> NewCond(BBI.BrCond);
if (ReserveCond)
if (ReverseCond) {
std::swap(CvtBBI, NextBBI);
TII->ReverseBranchCondition(NewCond);
}
FeasibilityAnalysis(*CvtBBI, NewCond);
if (!CvtBBI->isPredicable)
return false;