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Replace intersectWith with maximalIntersectWith. The latter guarantees that

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all values belonging to the intersection will belong to the resulting range.
The former was inconsistent about that point (either way is fine, just pick
one.) This is part of PR4545.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@76289 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nick Lewycky
2009-07-18 06:34:42 +00:00
parent d370d776aa
commit 3a4a884c16
5 changed files with 29 additions and 85 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/Support/ConstantRange.cpp
+5 -43
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@@ -275,49 +275,11 @@ ConstantRange::intersect1Wrapped(const ConstantRange &LHS,
}
/// intersectWith - Return the range that results from the intersection of this
/// range with another range.
///
/// 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.intersectWith(B) might not be equal to B.intersectWith(A).
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()) {
APInt L = APIntOps::umax(Lower, CR.Lower);
APInt U = APIntOps::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...
APInt L = APIntOps::umax(Lower, CR.Lower);
APInt U = APIntOps::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!");
@@ -326,7 +288,7 @@ ConstantRange::maximalIntersectWith(const ConstantRange &CR) const {
if (CR.isEmptySet() || isFullSet()) return CR;
if (!isWrappedSet() && CR.isWrappedSet())
return CR.maximalIntersectWith(*this);
return CR.intersectWith(*this);
if (!isWrappedSet() && !CR.isWrappedSet()) {
if (Lower.ult(CR.Lower)) {