[runtime] Add PositiveNumberToUint32 helper to avoid double to uint roundtrip

test/cctest/test-conversions.cc

Index: test/cctest/test-conversions.cc
diff --git a/test/cctest/test-conversions.cc b/test/cctest/test-conversions.cc
index d13badd20273ad31a236f4673b8758b190e4da9f..65cd96e0dffe42419ca3d0e65eb5f791a121ae76 100644
--- a/test/cctest/test-conversions.cc
+++ b/test/cctest/test-conversions.cc
@@ -456,3 +456,49 @@ TEST(TryNumberToSizeWithMaxSizePlusOne) {
     CHECK(!TryNumberToSize(*heap_number, &result));
   }
 }
+
+TEST(PositiveNumberToUint32) {
+  i::Isolate* isolate = CcTest::i_isolate();
+  i::Factory* factory = isolate->factory();
+  uint32_t max = std::numeric_limits<uint32_t>::max();
+  HandleScope scope(isolate);
+  // Test Smi conversions.
+  Handle<Object> number = handle(Smi::FromInt(0), isolate);
+  CHECK_EQ(PositiveNumberToUint32(*number), 0u);
+  number = handle(Smi::FromInt(-1), isolate);
+  CHECK_EQ(PositiveNumberToUint32(*number), 0u);
+  number = handle(Smi::FromInt(-1), isolate);
+  CHECK_EQ(PositiveNumberToUint32(*number), 0u);
+  number = handle(Smi::FromInt(Smi::kMinValue), isolate);
+  CHECK_EQ(PositiveNumberToUint32(*number), 0u);
+  number = handle(Smi::FromInt(Smi::kMaxValue), isolate);
+  CHECK_EQ(PositiveNumberToUint32(*number),
+           static_cast<uint32_t>(Smi::kMaxValue));
+  // Test Double conversions.
+  number = factory->NewHeapNumber(0.0);
+  CHECK_EQ(PositiveNumberToUint32(*number), 0u);
+  number = factory->NewHeapNumber(0.999);
+  CHECK_EQ(PositiveNumberToUint32(*number), 0u);
+  number = factory->NewHeapNumber(1.999);
+  CHECK_EQ(PositiveNumberToUint32(*number), 1u);
+  number = factory->NewHeapNumber(-12.0);
+  CHECK_EQ(PositiveNumberToUint32(*number), 0u);
+  number = factory->NewHeapNumber(12000.0);
+  CHECK_EQ(PositiveNumberToUint32(*number), 12000u);
+  number = factory->NewHeapNumber(static_cast<double>(Smi::kMaxValue) + 1);
+  CHECK_EQ(PositiveNumberToUint32(*number),
+           static_cast<uint32_t>(Smi::kMaxValue) + 1);
+  number = factory->NewHeapNumber(max);
+  CHECK_EQ(PositiveNumberToUint32(*number), max);
+  number = factory->NewHeapNumber(static_cast<double>(max) * 1000);
+  CHECK_EQ(PositiveNumberToUint32(*number), max);
+  number = factory->NewHeapNumber(std::numeric_limits<double>::max());
+  CHECK_EQ(PositiveNumberToUint32(*number), max);
+  number = factory->NewHeapNumber(std::numeric_limits<double>::infinity());
+  CHECK_EQ(PositiveNumberToUint32(*number), max);
+  number =
+      factory->NewHeapNumber(-1.0 * std::numeric_limits<double>::infinity());
+  CHECK_EQ(PositiveNumberToUint32(*number), 0u);
+  number = factory->NewHeapNumber(std::nan(""));
+  CHECK_EQ(PositiveNumberToUint32(*number), 0u);
+}