Fix a bug summing two full sets. The overflow checking doesn't handle sets as

large as the full set, only those one size smaller. Thanks to Daniel Dunbar
who found this bug using Klee!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75443 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Support/ConstantRange.cpp b/lib/Support/ConstantRange.cpp
index 04a1b68e0728dfa8e2789ec57a12b043286379e5..8bab53779528a98b89e6b063b7fce63852ef29bb 100644 (file)
--- a/lib/Support/ConstantRange.cpp
+++ b/lib/Support/ConstantRange.cpp
@@ -533,6 +533,8 @@ ConstantRange
 ConstantRange::add(const ConstantRange &Other) const {
   if (isEmptySet() || Other.isEmptySet())
     return ConstantRange(getBitWidth(), /*isFullSet=*/false);
+  if (isFullSet() || Other.isFullSet())
+    return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 
   APInt Spread_X = getSetSize(), Spread_Y = Other.getSetSize();
   APInt NewLower = getLower() + Other.getLower();

diff --git a/unittests/Support/ConstantRangeTest.cpp b/unittests/Support/ConstantRangeTest.cpp
index 891c209f11c02f0005ec60796a08705ffeb951e1..cd91a9e103cf5c6bafdddb3864ddfd6e844d130c 100644 (file)
--- a/unittests/Support/ConstantRangeTest.cpp
+++ b/unittests/Support/ConstantRangeTest.cpp
@@ -239,6 +239,7 @@ TEST_F(ConstantRangeTest, SubtractAPInt) {
 
 TEST_F(ConstantRangeTest, Add) {
   EXPECT_TRUE(Full.add(APInt(16, 4)).isFullSet());
+  EXPECT_EQ(Full.add(Full), Full);
   EXPECT_EQ(Full.add(Empty), Empty);
   EXPECT_EQ(Full.add(One), Full);
   EXPECT_EQ(Full.add(Some), Full);