[nix-shell:~/dev/zig/build-release]$ cat test.zig
export fn _start() noreturn {
    add(3, 4);

    exit();
}

fn add(a: u32, b: u32) void {
    const c = a + b; // 7
    const d = a + c; // 10
    const e = d + b; // 14
    const f = d + e; // 24
    const g = e + f; // 38
    const h = f + g; // 62
    const i = g + h; // 100
    const j = i + d; // 110
    assert(j == 110);
}

pub fn assert(ok: bool) void {
    if (!ok) unreachable; // assertion failure
}

fn exit() noreturn {
    asm volatile ("syscall"
        :
        : [number] "{rax}" (231),
          [arg1] "{rdi}" (0)
        : "rcx", "r11", "memory"
    );
    unreachable;
}

[nix-shell:~/dev/zig/build-release]$ time ./zig-cache/bin/zig build-exe test.zig 

real	0m0.004s
user	0m0.003s
sys	0m0.001s

[nix-shell:~/dev/zig/build-release]$ strace ./test
execve("./test", ["./test"], 0x7ffc9dc8ae90 /* 128 vars */) = 0
exit_group(0)                           = ?
+++ exited with 0 +++

[nix-shell:~/dev/zig/build-release]$ objdump -d ./test -M intel

./test:     file format elf64-x86-64


Disassembly of section .text:

0000000008000000 <_start>:
 8000000:	55                   	push   rbp
 8000001:	48 89 e5             	mov    rbp,rsp
 8000004:	bf 03 00 00 00       	mov    edi,0x3
 8000009:	be 04 00 00 00       	mov    esi,0x4
 800000e:	ff 14 25 08 00 00 04 	call   QWORD PTR ds:0x4000008
 8000015:	ff 14 25 10 00 00 04 	call   QWORD PTR ds:0x4000010
 800001c:	5d                   	pop    rbp
 800001d:	c3                   	ret    
 800001e:	79 73                	jns    8000093 <assert+0x18>
 8000020:	63 61 6c             	movsxd esp,DWORD PTR [rcx+0x6c]
 8000023:	6c                   	ins    BYTE PTR es:[rdi],dx
	...

0000000008000025 <add>:
 8000025:	55                   	push   rbp
 8000026:	48 89 e5             	mov    rbp,rsp
 8000029:	48 8b c6             	mov    rax,rsi
 800002c:	48 01 f8             	add    rax,rdi
 800002f:	48 01 c7             	add    rdi,rax
 8000032:	48 01 fe             	add    rsi,rdi
 8000035:	48 8b c6             	mov    rax,rsi
 8000038:	48 01 f8             	add    rax,rdi
 800003b:	48 01 c6             	add    rsi,rax
 800003e:	48 01 f0             	add    rax,rsi
 8000041:	48 01 c6             	add    rsi,rax
 8000044:	48 01 fe             	add    rsi,rdi
 8000047:	48 83 fe 6e          	cmp    rsi,0x6e
 800004b:	48 0f 94 c7          	rex.W sete dil
 800004f:	ff 14 25 18 00 00 04 	call   QWORD PTR ds:0x4000018
 8000056:	5d                   	pop    rbp
 8000057:	c3                   	ret    
 8000058:	00 00                	add    BYTE PTR [rax],al
 800005a:	31 ff                	xor    edi,edi
 800005c:	0f 05                	syscall 
 800005e:	cc                   	int3   
 800005f:	55                   	push   rbp
 8000060:	48 55                	rex.W push rbp
 8000062:	48 89 e5             	mov    rbp,rsp
 8000065:	55                   	push   rbp
 8000066:	48 89 e5             	mov    rbp,rsp

0000000008000069 <exit>:
 8000069:	55                   	push   rbp
 800006a:	48 89 e5             	mov    rbp,rsp
 800006d:	b8 e7 00 00 00       	mov    eax,0xe7
 8000072:	31 ff                	xor    edi,edi
 8000074:	0f 05                	syscall 
 8000076:	cc                   	int3   
 8000077:	55                   	push   rbp
 8000078:	48 89 e5             	mov    rbp,rsp

000000000800007b <assert>:
 800007b:	55                   	push   rbp
 800007c:	48 89 e5             	mov    rbp,rsp
 800007f:	48 83 f7 01          	xor    rdi,0x1
 8000083:	48 f6 c7 01          	rex.W test dil,0x1
 8000087:	0f 84 01 00 00 00    	je     800008e <assert+0x13>
 800008d:	cc                   	int3   
 800008e:	e9 00 00 00 00       	jmp    8000093 <assert+0x18>
 8000093:	5d                   	pop    rbp
 8000094:	c3                   	ret    
 8000095:	7b 72                	jnp    8000109 <exit__anon_2+0x5c>
 8000097:	61                   	(bad)  
 8000098:	78 7b                	js     8000115 <exit__anon_2+0x68>
 800009a:	72 61                	jb     80000fd <exit__anon_2+0x50>
 800009c:	78                   	.byte 0x78

000000000800009d <exit__anon_0>:
 800009d:	7b 72 61 78 7d 00 64 69                             {rax}.di

00000000080000a5 <exit__anon_1>:
 80000a5:	7b 72 64 69 7d 00 73 63                             {rdi}.sc

00000000080000ad <exit__anon_2>:
 80000ad:	73 79 73 63 61 6c 6c 00                             syscall.