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Implement union of wrapped sets.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35534 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky 2007-04-01 03:47:44 +00:00
parent a697b8d83d
commit 9babd0e0f2
1 changed files with 65 additions and 7 deletions
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72
lib/Support/ConstantRange.cpp
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@ -250,9 +250,9 @@ ConstantRange ConstantRange::intersectWith(const ConstantRange &CR) const {
/// 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.
/// 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() &&
@ -261,13 +261,71 @@ ConstantRange ConstantRange::unionWith(const ConstantRange &CR) const {
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 (!contains(CR.Lower))
L = APIntOps::umin(L, CR.Lower);
if (!isWrappedSet() && !CR.isWrappedSet()) {
if (CR.Lower.ult(L))
L = CR.Lower;
if (!contains(CR.Upper - 1))
U = APIntOps::umax(U, CR.Upper);
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);
}