Re-land "Clusterfuzz identified overflow check needed in dehoisting."

test/cctest/test-utils.cc

Index: test/cctest/test-utils.cc
diff --git a/test/cctest/test-utils.cc b/test/cctest/test-utils.cc
index 09206387ac7ceed3ef3b2dd0efa0f2b7a3fecbaf..3b866065efbc7f0fb4c8bcb085472956d6577ee7 100644
--- a/test/cctest/test-utils.cc
+++ b/test/cctest/test-utils.cc
@@ -218,3 +218,33 @@ TEST(SequenceCollectorRegression) {
   CHECK_EQ(0, strncmp("0123456789012345678901234567890123",
                       seq.start(), seq.length()));
 }
+
+
+#define MAX_VALUE(type) std::numeric_limits<type>::max()
+
+TEST(OverflowChecks) {
+  // int32_t
+  CHECK(!MultiplyOverflows<int32_t>(50, 50));
+  CHECK(MultiplyOverflows<int32_t>(MAX_VALUE(int32_t), 4));
+
+  CHECK(!AdditionOverflows<int32_t>(50, 50));
+  CHECK(!AdditionOverflows<int32_t>(MAX_VALUE(int32_t) - 1, 1));
+  CHECK(AdditionOverflows<int32_t>(MAX_VALUE(int32_t), 1));
+
+  // uint32_t
+  CHECK(!MultiplyOverflows<uint32_t>(MAX_VALUE(int32_t), 2));
+  CHECK(MultiplyOverflows<uint32_t>(MAX_VALUE(int32_t), 4));
+
+  CHECK(!AdditionOverflows<uint32_t>(MAX_VALUE(int32_t), 1));
+  CHECK(AdditionOverflows<uint32_t>(MAX_VALUE(uint32_t), 1));
+
+  // signed char
+  CHECK(AdditionOverflows<int8_t>(MAX_VALUE(int8_t), 1));
+  CHECK(MultiplyOverflows<int8_t>(64, 4));
+
+  // unsigned char
+  CHECK(!AdditionOverflows<uint8_t>(MAX_VALUE(int8_t), 1));
+  CHECK(AdditionOverflows<uint8_t>(MAX_VALUE(uint8_t), 1));
+  CHECK(!MultiplyOverflows<uint8_t>(64, 3));
+  CHECK(MultiplyOverflows<uint8_t>(64, 4));
+}