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[LVI] Split solveBlockValueConstantRange into two [NFC] 

This function handled both unary and binary operators.  Cloning and specializing leads to much easier to follow code with minimal duplicatation.

llvm-svn: 267438
This commit is contained in:
Philip Reames 2016-04-25 18:30:31 +00:00
parent d194e51726
commit 6671577eb3
1 changed files with 63 additions and 31 deletions
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94
llvm/lib/Analysis/LazyValueInfo.cpp
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@ -455,10 +455,12 @@ namespace {
bool solveBlockValuePHINode(LVILatticeVal &BBLV,
PHINode *PN, BasicBlock *BB);
bool solveBlockValueSelect(LVILatticeVal &BBLV,
SelectInst *S, BasicBlock *BB);
bool solveBlockValueConstantRange(LVILatticeVal &BBLV,
Instruction *BBI, BasicBlock *BB);
void intersectAssumeBlockValueConstantRange(Value *Val, LVILatticeVal &BBLV,
SelectInst *S, BasicBlock *BB);
bool solveBlockValueBinaryOp(LVILatticeVal &BBLV,
Instruction *BBI, BasicBlock *BB);
bool solveBlockValueCast(LVILatticeVal &BBLV,
Instruction *BBI, BasicBlock *BB);
void intersectAssumeBlockValueConstantRange(Value *Val, LVILatticeVal &BBLV,
Instruction *BBI);
void solve();
@ -670,7 +672,7 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) {
}
if (isa<CastInst>(BBI) && BBI->getType()->isIntegerTy()) {
if (!solveBlockValueConstantRange(Res, BBI, BB))
if (!solveBlockValueCast(Res, BBI, BB))
return false;
insertResult(Val, BB, Res);
return true;
@ -678,7 +680,7 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) {
BinaryOperator *BO = dyn_cast<BinaryOperator>(BBI);
if (BO && isa<ConstantInt>(BO->getOperand(1))) {
if (!solveBlockValueConstantRange(Res, BBI, BB))
if (!solveBlockValueBinaryOp(Res, BBI, BB))
return false;
insertResult(Val, BB, Res);
return true;
@ -993,9 +995,9 @@ bool LazyValueInfoCache::solveBlockValueSelect(LVILatticeVal &BBLV,
return true;
}
bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV,
Instruction *BBI,
BasicBlock *BB) {
bool LazyValueInfoCache::solveBlockValueCast(LVILatticeVal &BBLV,
Instruction *BBI,
BasicBlock *BB) {
// Figure out the range of the LHS. If that fails, bail.
if (!hasBlockValue(BBI->getOperand(0), BB)) {
if (pushBlockValue(std::make_pair(BB, BBI->getOperand(0))))
@ -1010,19 +1012,61 @@ bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV,
BBLV.markOverdefined();
return true;
}
ConstantRange LHSRange = LHSVal.getConstantRange();
ConstantRange RHSRange(1);
IntegerType *ResultTy = cast<IntegerType>(BBI->getType());
if (isa<BinaryOperator>(BBI)) {
if (ConstantInt *RHS = dyn_cast<ConstantInt>(BBI->getOperand(1))) {
RHSRange = ConstantRange(RHS->getValue());
} else {
BBLV.markOverdefined();
return true;
}
// NOTE: We're currently limited by the set of operations that ConstantRange
// can evaluate symbolically. Enhancing that set will allows us to analyze
// more definitions.
LVILatticeVal Result;
switch (BBI->getOpcode()) {
case Instruction::Trunc:
Result.markConstantRange(LHSRange.truncate(ResultTy->getBitWidth()));
break;
case Instruction::SExt:
Result.markConstantRange(LHSRange.signExtend(ResultTy->getBitWidth()));
break;
case Instruction::ZExt:
Result.markConstantRange(LHSRange.zeroExtend(ResultTy->getBitWidth()));
break;
case Instruction::BitCast:
Result.markConstantRange(LHSRange);
break;
// Unhandled instructions are overdefined.
default:
DEBUG(dbgs() << " compute BB '" << BB->getName()
<< "' - overdefined (unknown cast).\n");
Result.markOverdefined();
break;
}
BBLV = Result;
return true;
}
bool LazyValueInfoCache::solveBlockValueBinaryOp(LVILatticeVal &BBLV,
Instruction *BBI,
BasicBlock *BB) {
// Figure out the range of the LHS. If that fails, bail.
if (!hasBlockValue(BBI->getOperand(0), BB)) {
if (pushBlockValue(std::make_pair(BB, BBI->getOperand(0))))
return false;
BBLV.markOverdefined();
return true;
}
LVILatticeVal LHSVal = getBlockValue(BBI->getOperand(0), BB);
intersectAssumeBlockValueConstantRange(BBI->getOperand(0), LHSVal, BBI);
if (!LHSVal.isConstantRange()) {
BBLV.markOverdefined();
return true;
}
ConstantRange LHSRange = LHSVal.getConstantRange();
ConstantInt *RHS = cast<ConstantInt>(BBI->getOperand(1));
ConstantRange RHSRange = ConstantRange(RHS->getValue());
// NOTE: We're currently limited by the set of operations that ConstantRange
// can evaluate symbolically. Enhancing that set will allows us to analyze
// more definitions.
@ -1046,18 +1090,6 @@ bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV,
case Instruction::LShr:
Result.markConstantRange(LHSRange.lshr(RHSRange));
break;
case Instruction::Trunc:
Result.markConstantRange(LHSRange.truncate(ResultTy->getBitWidth()));
break;
case Instruction::SExt:
Result.markConstantRange(LHSRange.signExtend(ResultTy->getBitWidth()));
break;
case Instruction::ZExt:
Result.markConstantRange(LHSRange.zeroExtend(ResultTy->getBitWidth()));
break;
case Instruction::BitCast:
Result.markConstantRange(LHSRange);
break;
case Instruction::And:
Result.markConstantRange(LHSRange.binaryAnd(RHSRange));
break;
@ -1068,7 +1100,7 @@ bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV,
// Unhandled instructions are overdefined.
default:
DEBUG(dbgs() << " compute BB '" << BB->getName()
<< "' - overdefined because inst def found.\n");
<< "' - overdefined (unknown binary operator).\n");
Result.markOverdefined();
break;
}