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-rw-r--r--include/llvm/Support/ConstantRange.h4
-rw-r--r--lib/Support/ConstantRange.cpp6
-rw-r--r--unittests/Support/ConstantRangeTest.cpp17
3 files changed, 27 insertions, 0 deletions
diff --git a/include/llvm/Support/ConstantRange.h b/include/llvm/Support/ConstantRange.h
index ced3a2c..90dd69f 100644
--- a/include/llvm/Support/ConstantRange.h
+++ b/include/llvm/Support/ConstantRange.h
@@ -155,6 +155,10 @@ public:
/// constant range.
ConstantRange subtract(const APInt &CI) const;
+ /// \brief Subtract the specified range from this range (aka relative
+ /// complement of the sets).
+ ConstantRange difference(const ConstantRange &CR) const;
+
/// intersectWith - 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
diff --git a/lib/Support/ConstantRange.cpp b/lib/Support/ConstantRange.cpp
index 61d333f..91d086b 100644
--- a/lib/Support/ConstantRange.cpp
+++ b/lib/Support/ConstantRange.cpp
@@ -248,6 +248,12 @@ ConstantRange ConstantRange::subtract(const APInt &Val) const {
return ConstantRange(Lower - Val, Upper - Val);
}
+/// \brief Subtract the specified range from this range (aka relative complement
+/// of the sets).
+ConstantRange ConstantRange::difference(const ConstantRange &CR) const {
+ return intersectWith(CR.inverse());
+}
+
/// intersectWith - 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
diff --git a/unittests/Support/ConstantRangeTest.cpp b/unittests/Support/ConstantRangeTest.cpp
index a562080..72540c6 100644
--- a/unittests/Support/ConstantRangeTest.cpp
+++ b/unittests/Support/ConstantRangeTest.cpp
@@ -289,6 +289,23 @@ TEST_F(ConstantRangeTest, UnionWith) {
ConstantRange(16));
}
+TEST_F(ConstantRangeTest, SetDifference) {
+ EXPECT_EQ(Full.difference(Empty), Full);
+ EXPECT_EQ(Full.difference(Full), Empty);
+ EXPECT_EQ(Empty.difference(Empty), Empty);
+ EXPECT_EQ(Empty.difference(Full), Empty);
+
+ ConstantRange A(APInt(16, 3), APInt(16, 7));
+ ConstantRange B(APInt(16, 5), APInt(16, 9));
+ ConstantRange C(APInt(16, 3), APInt(16, 5));
+ ConstantRange D(APInt(16, 7), APInt(16, 9));
+ ConstantRange E(APInt(16, 5), APInt(16, 4));
+ ConstantRange F(APInt(16, 7), APInt(16, 3));
+ EXPECT_EQ(A.difference(B), C);
+ EXPECT_EQ(B.difference(A), D);
+ EXPECT_EQ(E.difference(A), F);
+}
+
TEST_F(ConstantRangeTest, SubtractAPInt) {
EXPECT_EQ(Full.subtract(APInt(16, 4)), Full);
EXPECT_EQ(Empty.subtract(APInt(16, 4)), Empty);