Fix the implementation of ConstantRange::sub(ConstantRange). Patch by Xi Wang!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133648 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Support/ConstantRange.cpp b/lib/Support/ConstantRange.cpp
index 493f708..81382d0 100644 (file)
--- a/lib/Support/ConstantRange.cpp
+++ b/lib/Support/ConstantRange.cpp
@@ -529,8 +529,8 @@ ConstantRange::sub(const ConstantRange &Other) const {
     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 
   APInt Spread_X = getSetSize(), Spread_Y = Other.getSetSize();
-  APInt NewLower = getLower() - Other.getLower();
-  APInt NewUpper = getUpper() - Other.getUpper() + 1;
+  APInt NewLower = getLower() - Other.getUpper() + 1;
+  APInt NewUpper = getUpper() - Other.getLower();
   if (NewLower == NewUpper)
     return ConstantRange(getBitWidth(), /*isFullSet=*/true);
 

diff --git a/unittests/Support/ConstantRangeTest.cpp b/unittests/Support/ConstantRangeTest.cpp
index 161e2cf..742bcb4 100644 (file)
--- a/unittests/Support/ConstantRangeTest.cpp
+++ b/unittests/Support/ConstantRangeTest.cpp
@@ -299,6 +299,8 @@ TEST_F(ConstantRangeTest, Sub) {
   EXPECT_EQ(Empty.sub(APInt(16, 4)), Empty);
   EXPECT_EQ(Some.sub(APInt(16, 4)),
             ConstantRange(APInt(16, 0x6), APInt(16, 0xaa6)));
+  EXPECT_EQ(Some.sub(Some),
+            ConstantRange(APInt(16, 0xf561), APInt(16, 0xaa0)));
   EXPECT_EQ(Wrap.sub(APInt(16, 4)),
             ConstantRange(APInt(16, 0xaa6), APInt(16, 0x6)));
   EXPECT_EQ(One.sub(APInt(16, 4)),