merging_functions.rs

#![feature(test)]
use std::hint::black_box;

#[inline(never)]
fn calc1(n: u32) -> u32 {
    n * n
}

#[inline(never)]
fn calc2(n: u32) -> u32 {
    n.pow(2)
}

fn main() {
    let input = black_box(7);
    
    let _a = calc1(input);
    let _b = calc2(input);
    
    println!("{} {}", _a, _b);
}

Run on play.rust-lang.org

...

playground::calc1: # @playground::calc1
# %bb.0:
	movl	%edi, %eax
	imull	%edi, %eax
	retq
                                        # -- End function

playground::main: # @playground::main
# %bb.0:
	pushq	%rbx
	subq	$96, %rsp
	movl	$7, 16(%rsp)
	leaq	16(%rsp), %rax
	#APP
	#NO_APP
	movl	16(%rsp), %ebx
	movl	%ebx, %edi
	callq	playground::calc1
	movl	%eax, 8(%rsp)
	movl	%ebx, %edi
	callq	playground::calc1
	movl	%eax, 12(%rsp)
	leaq	8(%rsp), %rax
	movq	%rax, 64(%rsp)

...