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

test/cctest/test-utils.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 200 matching lines @@
 TEST(SequenceCollectorRegression) {
   SequenceCollector<char> collector(16);
   collector.StartSequence();
   collector.Add('0');
   collector.AddBlock(
       i::Vector<const char>("12345678901234567890123456789012", 32));
   i::Vector<char> seq = collector.EndSequence();
   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));
+}