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[NFC] Introduce a 'struct Range' for IRCE

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Use the struct instead of a std::pair<Value *, Value *>.  This makes a
Range an obviously immutable object, and we can now assert that a
range is well-typed (Begin->getType() == End->getType()) on its
construction.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226804 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Sanjoy Das 2015-01-22 09:32:02 +00:00
parent deb2e51099
commit b51b170ce4
1 changed files with 27 additions and 17 deletions
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44
lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp
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@ -138,9 +138,23 @@ public:
BranchInst *getBranch() const { return Branch; }
/// Represents an integer range [Range.first, Range.second). If Range.second
/// < Range.first, then the value denotes the empty range.
typedef std::pair<Value *, Value *> Range;
/// Represents an signed integer range [Range.getBegin(), Range.getEnd()). If
/// R.getEnd() sle R.getBegin(), then R denotes the empty range.
class Range {
Value *Begin;
Value *End;
public:
Range(Value *Begin, Value *End) : Begin(Begin), End(End) {
assert(Begin->getType() == End->getType() && "ill-typed range!");
}
Type *getType() const { return Begin->getType(); }
Value *getBegin() const { return Begin; }
Value *getEnd() const { return End; }
};
typedef SpecificBumpPtrAllocator<InductiveRangeCheck> AllocatorTy;
/// This is the value the condition of the branch needs to evaluate to for the
@ -710,9 +724,7 @@ Optional<LoopConstrainer::SubRanges>
LoopConstrainer::calculateSubRanges(Value *&HeaderCountOut) const {
IntegerType *Ty = cast<IntegerType>(LatchTakenCount->getType());
assert(Range.first->getType() == Range.second->getType() &&
"ill-typed range!");
if (Range.first->getType() != Ty)
if (Range.getType() != Ty)
return None;
SCEVExpander Expander(SE, "irce");
@ -731,8 +743,8 @@ LoopConstrainer::calculateSubRanges(Value *&HeaderCountOut) const {
ConstantInt *One = ConstantInt::get(Ty, 1);
HeaderCountOut = MaybeSimplify(B.CreateAdd(LatchCountV, One, "header.count"));
const SCEV *RangeBegin = SE.getSCEV(Range.first);
const SCEV *RangeEnd = SE.getSCEV(Range.second);
const SCEV *RangeBegin = SE.getSCEV(Range.getBegin());
const SCEV *RangeEnd = SE.getSCEV(Range.getEnd());
const SCEV *HeaderCountSCEV = SE.getSCEV(HeaderCountOut);
const SCEV *Zero = SE.getConstant(Ty, 0);
@ -741,12 +753,12 @@ LoopConstrainer::calculateSubRanges(Value *&HeaderCountOut) const {
bool ProvablyNoPreloop =
SE.isKnownPredicate(ICmpInst::ICMP_SLE, RangeBegin, Zero);
if (!ProvablyNoPreloop)
Result.ExitPreLoopAt = ConstructSMinOf(HeaderCountOut, Range.first, B);
Result.ExitPreLoopAt = ConstructSMinOf(HeaderCountOut, Range.getBegin(), B);
bool ProvablyNoPostLoop =
SE.isKnownPredicate(ICmpInst::ICMP_SLE, HeaderCountSCEV, RangeEnd);
if (!ProvablyNoPostLoop)
Result.ExitMainLoopAt = ConstructSMinOf(HeaderCountOut, Range.second, B);
Result.ExitMainLoopAt = ConstructSMinOf(HeaderCountOut, Range.getEnd(), B);
return Result;
}
@ -1127,26 +1139,24 @@ InductiveRangeCheck::computeSafeIterationSpace(ScalarEvolution &SE,
Value *Begin = MaybeSimplify(B.CreateNeg(OffsetV));
Value *End = MaybeSimplify(B.CreateSub(getLength(), OffsetV));
return std::make_pair(Begin, End);
return InductiveRangeCheck::Range(Begin, End);
}
static Optional<InductiveRangeCheck::Range>
IntersectRange(const Optional<InductiveRangeCheck::Range> &R1,
const InductiveRangeCheck::Range &R2, IRBuilder<> &B) {
assert(R2.first->getType() == R2.second->getType() && "ill-typed range!");
if (!R1.hasValue())
return R2;
auto &R1Value = R1.getValue();
// TODO: we could widen the smaller range and have this work; but for now we
// bail out to keep things simple.
if (R1Value.first->getType() != R2.first->getType())
if (R1Value.getType() != R2.getType())
return None;
Value *NewMin = ConstructSMaxOf(R1Value.first, R2.first, B);
Value *NewMax = ConstructSMinOf(R1Value.second, R2.second, B);
return std::make_pair(NewMin, NewMax);
Value *NewMin = ConstructSMaxOf(R1Value.getBegin(), R2.getBegin(), B);
Value *NewMax = ConstructSMinOf(R1Value.getEnd(), R2.getEnd(), B);
return InductiveRangeCheck::Range(NewMin, NewMax);
}
bool InductiveRangeCheckElimination::runOnLoop(Loop *L, LPPassManager &LPM) {