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[LVI] Code motion only [NFC] 

I introduced a declaration in 259583 to keep the diff readable.  This change just moves the definition up to remove the declaration again.

llvm-svn: 259585
This commit is contained in:
Philip Reames 2016-02-02 22:03:19 +00:00
parent 327081e251
commit ed8cd0d36e
1 changed files with 62 additions and 64 deletions
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126
llvm/lib/Analysis/LazyValueInfo.cpp
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@ -294,7 +294,68 @@ raw_ostream &operator<<(raw_ostream &OS, const LVILatticeVal &Val) {
}
}
static LVILatticeVal intersect(LVILatticeVal A, LVILatticeVal B);
/// Returns true if this lattice value represents at most one possible value.
/// This is as precise as any lattice value can get while still representing
/// reachable code.
static bool hasSingleValue(LVILatticeVal Val) {
if (Val.isConstantRange() &&
Val.getConstantRange().isSingleElement())
// Integer constants are single element ranges
return true;
if (Val.isConstant())
// Non integer constants
return true;
return false;
}
/// Combine two sets of facts about the same value into a single set of
/// facts. Note that this method is not suitable for merging facts along
/// different paths in a CFG; that's what the mergeIn function is for. This
/// is for merging facts gathered about the same value at the same location
/// through two independent means.
/// Notes:
/// * This method does not promise to return the most precise possible lattice
/// value implied by A and B. It is allowed to return any lattice element
/// which is at least as strong as *either* A or B (unless our facts
/// conflict, see below).
/// * Due to unreachable code, the intersection of two lattice values could be
/// contradictory. If this happens, we return some valid lattice value so as
/// not confuse the rest of LVI. Ideally, we'd always return Undefined, but
/// we do not make this guarantee. TODO: This would be a useful enhancement.
static LVILatticeVal intersect(LVILatticeVal A, LVILatticeVal B) {
// Undefined is the strongest state. It means the value is known to be along
// an unreachable path.
if (A.isUndefined())
return A;
if (B.isUndefined())
return B;
// If we gave up for one, but got a useable fact from the other, use it.
if (A.isOverdefined())
return B;
if (B.isOverdefined())
return A;
// Can't get any more precise than constants.
if (hasSingleValue(A))
return A;
if (hasSingleValue(B))
return B;
// Could be either constant range or not constant here.
if (!A.isConstantRange() || !B.isConstantRange()) {
// TODO: Arbitrary choice, could be improved
return A;
}
// Intersect two constant ranges
ConstantRange Range =
A.getConstantRange().intersectWith(B.getConstantRange());
// Note: An empty range is implicitly converted to overdefined internally.
// TODO: We could instead use Undefined here since we've proven a conflict
// and thus know this path must be unreachable.
return LVILatticeVal::getRange(Range);
}
//===----------------------------------------------------------------------===//
// LazyValueInfoCache Decl
@ -1040,69 +1101,6 @@ static bool getEdgeValueLocal(Value *Val, BasicBlock *BBFrom,
return false;
}
/// Returns true if this lattice value represents at most one possible value.
/// This is as precise as any lattice value can get while still representing
/// reachable code.
static bool hasSingleValue(LVILatticeVal Val) {
if (Val.isConstantRange() &&
Val.getConstantRange().isSingleElement())
// Integer constants are single element ranges
return true;
if (Val.isConstant())
// Non integer constants
return true;
return false;
}
/// Combine two sets of facts about the same value into a single set of
/// facts. Note that this method is not suitable for merging facts along
/// different paths in a CFG; that's what the mergeIn function is for. This
/// is for merging facts gathered about the same value at the same location
/// through two independent means.
/// Notes:
/// * This method does not promise to return the most precise possible lattice
/// value implied by A and B. It is allowed to return any lattice element
/// which is at least as strong as *either* A or B (unless our facts
/// conflict, see below).
/// * Due to unreachable code, the intersection of two lattice values could be
/// contradictory. If this happens, we return some valid lattice value so as
/// not confuse the rest of LVI. Ideally, we'd always return Undefined, but
/// we do not make this guarantee. TODO: This would be a useful enhancement.
static LVILatticeVal intersect(LVILatticeVal A, LVILatticeVal B) {
// Undefined is the strongest state. It means the value is known to be along
// an unreachable path.
if (A.isUndefined())
return A;
if (B.isUndefined())
return B;
// If we gave up for one, but got a useable fact from the other, use it.
if (A.isOverdefined())
return B;
if (B.isOverdefined())
return A;
// Can't get any more precise than constants.
if (hasSingleValue(A))
return A;
if (hasSingleValue(B))
return B;
// Could be either constant range or not constant here.
if (!A.isConstantRange() || !B.isConstantRange()) {
// TODO: Arbitrary choice, could be improved
return A;
}
// Intersect two constant ranges
ConstantRange Range =
A.getConstantRange().intersectWith(B.getConstantRange());
// Note: An empty range is implicitly converted to overdefined internally.
// TODO: We could instead use Undefined here since we've proven a conflict
// and thus know this path must be unreachable.
return LVILatticeVal::getRange(Range);
}
/// \brief Compute the value of Val on the edge BBFrom -> BBTo or the value at
/// the basic block if the edge does not constrain Val.
bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom,