Benchmark: power of two vs shift left then unsigned shift right

Tests:

power of two
return 2**31
shift left then unsigned shift right
return 1<<31>>>0

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
power of two
shift left then unsigned shift right

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:128.0) Gecko/20100101 Goanna/6.7 Firefox/128.0 PaleMoon/33.8.1.2

Browser/OS: Pale Moon (Firefox Variant) 33 on Windows

View result in a separate tab

Test name	Executions per second
power of two	2233788160.0 Ops/sec
shift left then unsigned shift right	2407296768.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 9 months ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the provided JSON compares two different methods of computing the value of \(2^{31}\) in JavaScript:

1. **Power of Two Operation (`2**31`)**: This uses the exponentiation operator, which is a straightforward way to compute powers.
2. **Shift Left Then Unsigned Shift Right (`1 << 31 >>> 0`)**: This approach employs bitwise operations to achieve the same result. The left shift operator (`<<`) shifts the bits of the number to the left, effectively multiplying it by 2 for each position shifted. The unsigned right shift operator (`>>>`) is then applied to ensure the result is treated as an unsigned value.

### Pros and Cons of Approaches

#### Power of Two (`2**31`)
**Pros:**
- **Simplicity**: The syntax is straightforward and easy to read, making it clear that you are calculating a power of two.
- **Clarity**: It expresses the intent directly, which can be beneficial for maintainability.

**Cons:**
- **Performance**: In some environments, particularly older JavaScript engines, this operation might be slower compared to bitwise operations, especially if the engine does not optimize exponentiation well.

#### Shift Left Then Unsigned Shift Right (`1 << 31 >>> 0`)
**Pros:**
- **Performance**: Bitwise operations are generally faster since they are lower-level operations directly manipulating the binary representation of numbers.
- **Control**: This method of computing can be more efficient for certain applications, as it utilizes the binary nature of computers.

**Cons:**
- **Readability**: The syntax can be less intuitive for developers who might not be familiar with bitwise operations. It may require additional comments or documentation for clarity.
- **Limitations**: The usage of bitwise operators can lead to unexpected results if not handled carefully, especially with negative numbers or large values.

### Other Considerations
When selecting between these two methods, engineers should consider the following:
- **Browser Compatibility**: While modern JavaScript engines have improved significantly, older engines could impact the performance of the exponentiation operator. Hence, the environment in which the code is running is crucial.
- **Maintainability and Readability**: Future developers who might work with the code may find the clarity of the exponentiation operator preferable to the complexity of bitwise manipulations.

### Alternative Approaches
Apart from the methods tested in this benchmark, other techniques could include:
- **Math Library**: Using a library like `Math.pow(base, exponent)` to compute powers, which may offer additional handling for special cases like negative exponents or non-integer values.
- **Pre-computed Constants**: If the computation is fixed (as in computing \(2^{31}\)), simply using a constant defined upfront (e.g., `const VALUE = 2147483648;`) would be the most efficient but lacks dynamic calculation.

### Summary
The benchmark provides insight into the performance differences between the exponentiation operator and bitwise shifts. The power of two approach is simpler and clearer, while the bitwise method is generally more performant. The choice between these options should take into account the specific context of the application, including readability, performance needs, and compatibility with the JavaScript engine in use.

Related benchmarks:

power of two vs shift left then unsigned shift right (version: 1)

Comparing performance of: power of two vs shift left then unsigned shift right

Created: 9 months ago by: Guest

Jump to the latest result

power of two

shift left then unsigned shift right

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 9 months ago):