Fix UB in APInt::ashr
i64 -1, whose sign bit is the 0th one, can't be left shifted without invoking UB.
https://reviews.llvm.org/D23362
llvm-svn: 278280
diff --git a/llvm/unittests/ADT/APIntTest.cpp b/llvm/unittests/ADT/APIntTest.cpp
index 3a7c2d7..cbffdc0 100644
--- a/llvm/unittests/ADT/APIntTest.cpp
+++ b/llvm/unittests/ADT/APIntTest.cpp
@@ -32,6 +32,11 @@
EXPECT_FALSE(Shl[1]);
}
+TEST(APIntTest, i64_ArithmeticRightShiftNegative) {
+ const APInt neg_one(64, static_cast<uint64_t>(-1), true);
+ EXPECT_EQ(neg_one, neg_one.ashr(7));
+}
+
TEST(APIntTest, i128_NegativeCount) {
APInt Minus3(128, static_cast<uint64_t>(-3), true);
EXPECT_EQ(126u, Minus3.countLeadingOnes());