fix corner case in ConstantRange::intersectWith().
this fixes the missed optimization I was seeing in the CorrelatedValuePropagation pass

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157032 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/unittests/Support/ConstantRangeTest.cpp b/unittests/Support/ConstantRangeTest.cpp
index 742bcb4..5fcdcfd 100644
--- a/unittests/Support/ConstantRangeTest.cpp
+++ b/unittests/Support/ConstantRangeTest.cpp
@@ -232,6 +232,11 @@
   ConstantRange LHS(APInt(16, 4), APInt(16, 2));
   ConstantRange RHS(APInt(16, 6), APInt(16, 5));
   EXPECT_TRUE(LHS.intersectWith(RHS) == LHS);
+
+  // previous bug: intersection of [min, 3) and [2, max) should be 2
+  LHS = ConstantRange(APInt(32, -2147483648), APInt(32, 3));
+  RHS = ConstantRange(APInt(32, 2), APInt(32, 2147483648));
+  EXPECT_EQ(LHS.intersectWith(RHS), ConstantRange(APInt(32, 2)));
 }
 
 TEST_F(ConstantRangeTest, UnionWith) {