Is pow(x, 2) or x * x More Efficient for Squaring in C and C ?

What is more efficient? Using pow to square or just multiply it with itself?

In C, using x * x for squaring is generally more efficient than using pow(x, 2) because pow involves a function call with additional overhead.

However, in C , both approaches can be efficient due to compiler optimizations:

pow(x, 3) vs. x x x

In C , pow(x, 3) and x * x * x are usually equivalent in terms of efficiency. C 's std::pow function takes a more generic form (pow(double, double)), which handles exponents as floating-point numbers.

Specific Considerations:

• Optimization Level: Compilers may optimize either approach.
• Exponent: As the exponent gets larger, std::pow may become more efficient due to its optimized implementation for integer exponents.
• Data Types: If you're working with integer exponents and optimizing for speed, manually multiplying (e.g., x * x * x) can still be a better choice.

Here are the updated benchmarks for GCC and Clang, testing efficiency for different exponents:

Exponent	GCC (O3)	Clang (O3)
2	x * x slightly faster	Similar
3	x * x * x faster	Similar
4 and above	x * x * x * ... faster	Similar

Additional Notes:

• C's pow(double, double) is less efficient than std::pow in C due to the lack of function overloading.
• Using -ffast-math in GCC can significantly speed up std::pow for odd exponents.

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