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#include "lattice.h"
#include <type_traits>
namespace wasm::analysis {
struct SignLattice {
public:
enum Sign { BOTTOM, NEGATIVE, ZERO, POSITIVE, TOP };
private:
Sign value;
public:
static bool isTop(const SignLattice& element) { return element.value == TOP; }
static bool isBottom(const SignLattice& element) {
return element.value == BOTTOM;
}
static LatticeComparison compare(const SignLattice& left,
const SignLattice& right) {
if (left.value == right.value) {
return EQUAL;
} else if (left.value == BOTTOM || right.value == TOP) {
return LESS;
} else if (left.value == TOP || right.value == BOTTOM) {
return GREATER;
} else {
return NO_RELATION;
}
}
// Modifies the left lattice element to the least upper bound between
// it and the right hand lattice element in-place. Returns true
// if the left lattice element has been changed.
void getLeastUpperBound(const SignLattice& right) {
if (value == right.value || value == TOP || right.value == BOTTOM) {
return;
} else if (value == BOTTOM || right.value == TOP) {
value = right.value;
} else {
value = TOP;
}
}
};
static_assert(is_lattice<SignLattice>);
} // namespace wasm::analysis
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