forked from OSchip/llvm-project
473 lines
14 KiB
C++
473 lines
14 KiB
C++
//===-- ConstantRange.cpp - ConstantRange implementation ------------------===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Represent a range of possible values that may occur when the program is run
|
|
// for an integral value. This keeps track of a lower and upper bound for the
|
|
// constant, which MAY wrap around the end of the numeric range. To do this, it
|
|
// keeps track of a [lower, upper) bound, which specifies an interval just like
|
|
// STL iterators. When used with boolean values, the following are important
|
|
// ranges (other integral ranges use min/max values for special range values):
|
|
//
|
|
// [F, F) = {} = Empty set
|
|
// [T, F) = {T}
|
|
// [F, T) = {F}
|
|
// [T, T) = {F, T} = Full set
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Support/ConstantRange.h"
|
|
#include "llvm/Support/raw_ostream.h"
|
|
using namespace llvm;
|
|
|
|
/// Initialize a full (the default) or empty set for the specified type.
|
|
///
|
|
ConstantRange::ConstantRange(uint32_t BitWidth, bool Full) :
|
|
Lower(BitWidth, 0), Upper(BitWidth, 0) {
|
|
if (Full)
|
|
Lower = Upper = APInt::getMaxValue(BitWidth);
|
|
else
|
|
Lower = Upper = APInt::getMinValue(BitWidth);
|
|
}
|
|
|
|
/// Initialize a range to hold the single specified value.
|
|
///
|
|
ConstantRange::ConstantRange(const APInt & V) : Lower(V), Upper(V + 1) { }
|
|
|
|
ConstantRange::ConstantRange(const APInt &L, const APInt &U) :
|
|
Lower(L), Upper(U) {
|
|
assert(L.getBitWidth() == U.getBitWidth() &&
|
|
"ConstantRange with unequal bit widths");
|
|
assert((L != U || (L.isMaxValue() || L.isMinValue())) &&
|
|
"Lower == Upper, but they aren't min or max value!");
|
|
}
|
|
|
|
/// isFullSet - Return true if this set contains all of the elements possible
|
|
/// for this data-type
|
|
bool ConstantRange::isFullSet() const {
|
|
return Lower == Upper && Lower.isMaxValue();
|
|
}
|
|
|
|
/// isEmptySet - Return true if this set contains no members.
|
|
///
|
|
bool ConstantRange::isEmptySet() const {
|
|
return Lower == Upper && Lower.isMinValue();
|
|
}
|
|
|
|
/// isWrappedSet - Return true if this set wraps around the top of the range,
|
|
/// for example: [100, 8)
|
|
///
|
|
bool ConstantRange::isWrappedSet() const {
|
|
return Lower.ugt(Upper);
|
|
}
|
|
|
|
/// getSetSize - Return the number of elements in this set.
|
|
///
|
|
APInt ConstantRange::getSetSize() const {
|
|
if (isEmptySet())
|
|
return APInt(getBitWidth(), 0);
|
|
if (getBitWidth() == 1) {
|
|
if (Lower != Upper) // One of T or F in the set...
|
|
return APInt(2, 1);
|
|
return APInt(2, 2); // Must be full set...
|
|
}
|
|
|
|
// Simply subtract the bounds...
|
|
return Upper - Lower;
|
|
}
|
|
|
|
/// getUnsignedMax - Return the largest unsigned value contained in the
|
|
/// ConstantRange.
|
|
///
|
|
APInt ConstantRange::getUnsignedMax() const {
|
|
if (isFullSet() || isWrappedSet())
|
|
return APInt::getMaxValue(getBitWidth());
|
|
else
|
|
return getUpper() - 1;
|
|
}
|
|
|
|
/// getUnsignedMin - Return the smallest unsigned value contained in the
|
|
/// ConstantRange.
|
|
///
|
|
APInt ConstantRange::getUnsignedMin() const {
|
|
if (isFullSet() || (isWrappedSet() && getUpper() != 0))
|
|
return APInt::getMinValue(getBitWidth());
|
|
else
|
|
return getLower();
|
|
}
|
|
|
|
/// getSignedMax - Return the largest signed value contained in the
|
|
/// ConstantRange.
|
|
///
|
|
APInt ConstantRange::getSignedMax() const {
|
|
APInt SignedMax(APInt::getSignedMaxValue(getBitWidth()));
|
|
if (!isWrappedSet()) {
|
|
if (getLower().sle(getUpper() - 1))
|
|
return getUpper() - 1;
|
|
else
|
|
return SignedMax;
|
|
} else {
|
|
if ((getUpper() - 1).slt(getLower())) {
|
|
if (getLower() != SignedMax)
|
|
return SignedMax;
|
|
else
|
|
return getUpper() - 1;
|
|
} else {
|
|
return getUpper() - 1;
|
|
}
|
|
}
|
|
}
|
|
|
|
/// getSignedMin - Return the smallest signed value contained in the
|
|
/// ConstantRange.
|
|
///
|
|
APInt ConstantRange::getSignedMin() const {
|
|
APInt SignedMin(APInt::getSignedMinValue(getBitWidth()));
|
|
if (!isWrappedSet()) {
|
|
if (getLower().sle(getUpper() - 1))
|
|
return getLower();
|
|
else
|
|
return SignedMin;
|
|
} else {
|
|
if ((getUpper() - 1).slt(getLower())) {
|
|
if (getUpper() != SignedMin)
|
|
return SignedMin;
|
|
else
|
|
return getLower();
|
|
} else {
|
|
return getLower();
|
|
}
|
|
}
|
|
}
|
|
|
|
/// contains - Return true if the specified value is in the set.
|
|
///
|
|
bool ConstantRange::contains(const APInt &V) const {
|
|
if (Lower == Upper)
|
|
return isFullSet();
|
|
|
|
if (!isWrappedSet())
|
|
return Lower.ule(V) && V.ult(Upper);
|
|
else
|
|
return Lower.ule(V) || V.ult(Upper);
|
|
}
|
|
|
|
/// subtract - Subtract the specified constant from the endpoints of this
|
|
/// constant range.
|
|
ConstantRange ConstantRange::subtract(const APInt &Val) const {
|
|
assert(Val.getBitWidth() == getBitWidth() && "Wrong bit width");
|
|
// If the set is empty or full, don't modify the endpoints.
|
|
if (Lower == Upper)
|
|
return *this;
|
|
return ConstantRange(Lower - Val, Upper - Val);
|
|
}
|
|
|
|
|
|
// intersect1Wrapped - This helper function is used to intersect two ranges when
|
|
// it is known that LHS is wrapped and RHS isn't.
|
|
//
|
|
ConstantRange
|
|
ConstantRange::intersect1Wrapped(const ConstantRange &LHS,
|
|
const ConstantRange &RHS) {
|
|
assert(LHS.isWrappedSet() && !RHS.isWrappedSet());
|
|
|
|
// Check to see if we overlap on the Left side of RHS...
|
|
//
|
|
if (RHS.Lower.ult(LHS.Upper)) {
|
|
// We do overlap on the left side of RHS, see if we overlap on the right of
|
|
// RHS...
|
|
if (RHS.Upper.ugt(LHS.Lower)) {
|
|
// Ok, the result overlaps on both the left and right sides. See if the
|
|
// resultant interval will be smaller if we wrap or not...
|
|
//
|
|
if (LHS.getSetSize().ult(RHS.getSetSize()))
|
|
return LHS;
|
|
else
|
|
return RHS;
|
|
|
|
} else {
|
|
// No overlap on the right, just on the left.
|
|
return ConstantRange(RHS.Lower, LHS.Upper);
|
|
}
|
|
} else {
|
|
// We don't overlap on the left side of RHS, see if we overlap on the right
|
|
// of RHS...
|
|
if (RHS.Upper.ugt(LHS.Lower)) {
|
|
// Simple overlap...
|
|
return ConstantRange(LHS.Lower, RHS.Upper);
|
|
} else {
|
|
// No overlap...
|
|
return ConstantRange(LHS.getBitWidth(), false);
|
|
}
|
|
}
|
|
}
|
|
|
|
/// intersectWith - Return the range that results from the intersection of this
|
|
/// range with another range.
|
|
///
|
|
ConstantRange ConstantRange::intersectWith(const ConstantRange &CR) const {
|
|
assert(getBitWidth() == CR.getBitWidth() &&
|
|
"ConstantRange types don't agree!");
|
|
// Handle common special cases
|
|
if (isEmptySet() || CR.isFullSet())
|
|
return *this;
|
|
if (isFullSet() || CR.isEmptySet())
|
|
return CR;
|
|
|
|
if (!isWrappedSet()) {
|
|
if (!CR.isWrappedSet()) {
|
|
using namespace APIntOps;
|
|
APInt L = umax(Lower, CR.Lower);
|
|
APInt U = umin(Upper, CR.Upper);
|
|
|
|
if (L.ult(U)) // If range isn't empty...
|
|
return ConstantRange(L, U);
|
|
else
|
|
return ConstantRange(getBitWidth(), false);// Otherwise, empty set
|
|
} else
|
|
return intersect1Wrapped(CR, *this);
|
|
} else { // We know "this" is wrapped...
|
|
if (!CR.isWrappedSet())
|
|
return intersect1Wrapped(*this, CR);
|
|
else {
|
|
// Both ranges are wrapped...
|
|
using namespace APIntOps;
|
|
APInt L = umax(Lower, CR.Lower);
|
|
APInt U = umin(Upper, CR.Upper);
|
|
return ConstantRange(L, U);
|
|
}
|
|
}
|
|
return *this;
|
|
}
|
|
|
|
/// maximalIntersectWith - Return the range that results from the intersection
|
|
/// of this range with another range. The resultant range is guaranteed to
|
|
/// include all elements contained in both input ranges, and to have the
|
|
/// smallest possible set size that does so. Because there may be two
|
|
/// intersections with the same set size, A.maximalIntersectWith(B) might not
|
|
/// be equal to B.maximalIntersect(A).
|
|
ConstantRange ConstantRange::maximalIntersectWith(const ConstantRange &CR) const {
|
|
assert(getBitWidth() == CR.getBitWidth() &&
|
|
"ConstantRange types don't agree!");
|
|
|
|
// Handle common cases.
|
|
if ( isEmptySet() || CR.isFullSet()) return *this;
|
|
if (CR.isEmptySet() || isFullSet()) return CR;
|
|
|
|
if (!isWrappedSet() && CR.isWrappedSet())
|
|
return CR.maximalIntersectWith(*this);
|
|
|
|
if (!isWrappedSet() && !CR.isWrappedSet()) {
|
|
if (Lower.ult(CR.Lower)) {
|
|
if (Upper.ule(CR.Lower))
|
|
return ConstantRange(getBitWidth(), false);
|
|
|
|
if (Upper.ult(CR.Upper))
|
|
return ConstantRange(CR.Lower, Upper);
|
|
|
|
return CR;
|
|
} else {
|
|
if (Upper.ult(CR.Upper))
|
|
return *this;
|
|
|
|
if (Lower.ult(CR.Upper))
|
|
return ConstantRange(Lower, CR.Upper);
|
|
|
|
return ConstantRange(getBitWidth(), false);
|
|
}
|
|
}
|
|
|
|
if (isWrappedSet() && !CR.isWrappedSet()) {
|
|
if (CR.Lower.ult(Upper)) {
|
|
if (CR.Upper.ult(Upper))
|
|
return CR;
|
|
|
|
if (CR.Upper.ult(Lower))
|
|
return ConstantRange(CR.Lower, Upper);
|
|
|
|
if (getSetSize().ult(CR.getSetSize()))
|
|
return *this;
|
|
else
|
|
return CR;
|
|
} else if (CR.Lower.ult(Lower)) {
|
|
if (CR.Upper.ule(Lower))
|
|
return ConstantRange(getBitWidth(), false);
|
|
|
|
return ConstantRange(Lower, CR.Upper);
|
|
}
|
|
return CR;
|
|
}
|
|
|
|
if (CR.Upper.ult(Upper)) {
|
|
if (CR.Lower.ult(Upper)) {
|
|
if (getSetSize().ult(CR.getSetSize()))
|
|
return *this;
|
|
else
|
|
return CR;
|
|
}
|
|
|
|
if (CR.Lower.ult(Lower))
|
|
return ConstantRange(Lower, CR.Upper);
|
|
|
|
return CR;
|
|
} else if (CR.Upper.ult(Lower)) {
|
|
if (CR.Lower.ult(Lower))
|
|
return *this;
|
|
|
|
return ConstantRange(CR.Lower, Upper);
|
|
}
|
|
if (getSetSize().ult(CR.getSetSize()))
|
|
return *this;
|
|
else
|
|
return CR;
|
|
}
|
|
|
|
|
|
/// unionWith - Return the range that results from the union of this range with
|
|
/// another range. The resultant range is guaranteed to include the elements of
|
|
/// both sets, but may contain more. For example, [3, 9) union [12,15) is
|
|
/// [3, 15), which includes 9, 10, and 11, which were not included in either
|
|
/// set before.
|
|
///
|
|
ConstantRange ConstantRange::unionWith(const ConstantRange &CR) const {
|
|
assert(getBitWidth() == CR.getBitWidth() &&
|
|
"ConstantRange types don't agree!");
|
|
|
|
if ( isFullSet() || CR.isEmptySet()) return *this;
|
|
if (CR.isFullSet() || isEmptySet()) return CR;
|
|
|
|
if (!isWrappedSet() && CR.isWrappedSet()) return CR.unionWith(*this);
|
|
|
|
APInt L = Lower, U = Upper;
|
|
|
|
if (!isWrappedSet() && !CR.isWrappedSet()) {
|
|
if (CR.Lower.ult(L))
|
|
L = CR.Lower;
|
|
|
|
if (CR.Upper.ugt(U))
|
|
U = CR.Upper;
|
|
}
|
|
|
|
if (isWrappedSet() && !CR.isWrappedSet()) {
|
|
if ((CR.Lower.ult(Upper) && CR.Upper.ult(Upper)) ||
|
|
(CR.Lower.ugt(Lower) && CR.Upper.ugt(Lower))) {
|
|
return *this;
|
|
}
|
|
|
|
if (CR.Lower.ule(Upper) && Lower.ule(CR.Upper)) {
|
|
return ConstantRange(getBitWidth());
|
|
}
|
|
|
|
if (CR.Lower.ule(Upper) && CR.Upper.ule(Lower)) {
|
|
APInt d1 = CR.Upper - Upper, d2 = Lower - CR.Upper;
|
|
if (d1.ult(d2)) {
|
|
U = CR.Upper;
|
|
} else {
|
|
L = CR.Upper;
|
|
}
|
|
}
|
|
|
|
if (Upper.ult(CR.Lower) && CR.Upper.ult(Lower)) {
|
|
APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Upper;
|
|
if (d1.ult(d2)) {
|
|
U = CR.Lower + 1;
|
|
} else {
|
|
L = CR.Upper - 1;
|
|
}
|
|
}
|
|
|
|
if (Upper.ult(CR.Lower) && Lower.ult(CR.Upper)) {
|
|
APInt d1 = CR.Lower - Upper, d2 = Lower - CR.Lower;
|
|
|
|
if (d1.ult(d2)) {
|
|
U = CR.Lower + 1;
|
|
} else {
|
|
L = CR.Lower;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (isWrappedSet() && CR.isWrappedSet()) {
|
|
if (Lower.ult(CR.Upper) || CR.Lower.ult(Upper))
|
|
return ConstantRange(getBitWidth());
|
|
|
|
if (CR.Upper.ugt(U)) {
|
|
U = CR.Upper;
|
|
}
|
|
|
|
if (CR.Lower.ult(L)) {
|
|
L = CR.Lower;
|
|
}
|
|
|
|
if (L == U) return ConstantRange(getBitWidth());
|
|
}
|
|
|
|
return ConstantRange(L, U);
|
|
}
|
|
|
|
/// zeroExtend - Return a new range in the specified integer type, which must
|
|
/// be strictly larger than the current type. The returned range will
|
|
/// correspond to the possible range of values as if the source range had been
|
|
/// zero extended.
|
|
ConstantRange ConstantRange::zeroExtend(uint32_t DstTySize) const {
|
|
unsigned SrcTySize = getBitWidth();
|
|
assert(SrcTySize < DstTySize && "Not a value extension");
|
|
if (isFullSet())
|
|
// Change a source full set into [0, 1 << 8*numbytes)
|
|
return ConstantRange(APInt(DstTySize,0), APInt(DstTySize,1).shl(SrcTySize));
|
|
|
|
APInt L = Lower; L.zext(DstTySize);
|
|
APInt U = Upper; U.zext(DstTySize);
|
|
return ConstantRange(L, U);
|
|
}
|
|
|
|
/// signExtend - Return a new range in the specified integer type, which must
|
|
/// be strictly larger than the current type. The returned range will
|
|
/// correspond to the possible range of values as if the source range had been
|
|
/// sign extended.
|
|
ConstantRange ConstantRange::signExtend(uint32_t DstTySize) const {
|
|
unsigned SrcTySize = getBitWidth();
|
|
assert(SrcTySize < DstTySize && "Not a value extension");
|
|
if (isFullSet()) {
|
|
return ConstantRange(APInt::getHighBitsSet(DstTySize,DstTySize-SrcTySize+1),
|
|
APInt::getLowBitsSet(DstTySize, SrcTySize-1));
|
|
}
|
|
|
|
APInt L = Lower; L.sext(DstTySize);
|
|
APInt U = Upper; U.sext(DstTySize);
|
|
return ConstantRange(L, U);
|
|
}
|
|
|
|
/// truncate - Return a new range in the specified integer type, which must be
|
|
/// strictly smaller than the current type. The returned range will
|
|
/// correspond to the possible range of values as if the source range had been
|
|
/// truncated to the specified type.
|
|
ConstantRange ConstantRange::truncate(uint32_t DstTySize) const {
|
|
unsigned SrcTySize = getBitWidth();
|
|
assert(SrcTySize > DstTySize && "Not a value truncation");
|
|
APInt Size(APInt::getLowBitsSet(SrcTySize, DstTySize));
|
|
if (isFullSet() || getSetSize().ugt(Size))
|
|
return ConstantRange(DstTySize);
|
|
|
|
APInt L = Lower; L.trunc(DstTySize);
|
|
APInt U = Upper; U.trunc(DstTySize);
|
|
return ConstantRange(L, U);
|
|
}
|
|
|
|
/// print - Print out the bounds to a stream...
|
|
///
|
|
void ConstantRange::print(raw_ostream &OS) const {
|
|
OS << "[" << Lower << "," << Upper << ")";
|
|
}
|
|
|
|
/// dump - Allow printing from a debugger easily...
|
|
///
|
|
void ConstantRange::dump() const {
|
|
print(errs());
|
|
}
|