gistfile1.txt

$ cargo bench
    Finished release [optimized] target(s) in 0.0 secs
     Running target\release\deps\benching-22b624a5099107eb.exe

running 2 tests
test tests::loop_notrash ... bench:   1,053,106 ns/iter (+/- 162,958)
test tests::loop_trash   ... bench:   1,458,335 ns/iter (+/- 149,239)

test result: ok. 0 passed; 0 failed; 0 ignored; 2 measured

lib.s

rust_iter_notrash:
	incq	%rcx
	xorl	%r8d, %r8d
	xorl	%r9d, %r9d
.LBB0_1:
	movq	%r9, %rax
	leaq	-2(%rax,%r8,2), %r9
	movq	%r8, %rdx
.LBB0_2:
	cmpq	%rcx, %rdx
	jge	.LBB0_4
	leaq	1(%rdx), %r8
	addq	$2, %r9
	testb	$32, %dl
	movq	%r8, %rdx
	jne	.LBB0_2
	jmp	.LBB0_1
.LBB0_4:
	retq


rust_iter_trash:
	incq	%rcx
	xorl	%r8d, %r8d
	xorl	%r9d, %r9d
.LBB1_1:
	movq	%r9, %rax
	leaq	-2(%rax,%r8,2), %r9
	movq	%r8, %rdx
.LBB1_2:
	cmpq	%rcx, %rdx
	jge	.LBB1_4
	leaq	1(%rdx), %r8
	addq	$2, %r9
	testb	$1, %dl
	movq	%r8, %rdx
	jne	.LBB1_2
	jmp	.LBB1_1
.LBB1_4:
	retq

test.rs

extern crate test;

type T = isize;


#[no_mangle]
pub fn rust_iter_notrash(high: T) -> T {
    (0..high +1)
        .filter(|x| (x & 0x20) == 0)
        .map(|x| x * 2)
        .sum()
}

#[no_mangle]
pub fn rust_iter_trash(high: T) -> T {
    (0..high +1)
        .filter(|x| x % 2 == 0)
        .map(|x| x * 2)
        .sum()
}


#[cfg(test)]
mod tests {
    use test;

    #[bench]
    fn loop_notrash(b: &mut test::Bencher) {
        b.iter(||{
            assert!(::rust_iter_notrash(1_000_000) != 0);
        });
    }

    #[bench]
    fn loop_trash(b: &mut test::Bencher) {
        b.iter(||{
            assert!(::rust_iter_trash(1_000_000) != 0);
        });
    }
}