Small fibonacci bench (Rust, Swift, C)

rust_fib_bench

Fib bench (Rust, Swift, C) I added C to the discussion on
https://www.reddit.com/r/rust/comments/3wxi9x/why_is_rust_much_slower_than_swift_in_this_simple/

fib.c

#include <inttypes.h>
#include <stdio.h>

int64_t fib(int64_t n) {
  if (n <= 2) {
    return 1;
  } else {
    return fib(n - 1) + fib(n - 2);
  }
}

int main() {
  int64_t num = 45;
  printf("%"PRIi64"\n", fib(num));
  return 0;
}

fib.rs

// fib.rs // I've tried also i32, usize, but it is the same. I'm on 64bit
fn fib(n: i64) -> i64 {
    if n <= 2 {
        1
    } else {
        fib(n - 1) + fib(n - 2)
    }
}

fn main() {
    let num = 45;
    println!("{}", fib(num))
}

fib.swift

func fib(n: Int) -> Int {
    if n <= 2 {
        return 1
    } else {
        return (fib(n - 1) + fib(n - 2))
    }
}

let num = 45
print(fib(num))

Makefile

RUSTC := rustc
SWIFTC := swiftc

.PHONY: all
all: fib_rust fib_swift fib_c

fib_rust: fib.rs
	$(RUSTC) -O $< -o $@

fib_swift: fib.swift
	$(SWIFTC) -O $< -o $@

fib_c: fib.c
	$(CC) -O $< -o $@

.PHONY: bench
bench: fib_rust fib_swift fib_c
	@echo
	@$(RUSTC) --version
	@time ./fib_rust
	@echo
	@echo
	@$(SWIFTC) --version
	@time ./fib_swift
	@echo
	@echo
	@$(CC) --version
	@time ./fib_c
	@echo
	@echo

.PHONY: clean
clean:
	rm -f fib_rust fib_swift fib_c