#define NULL ((void *)0)
typedef unsigned long size_t; // Customize by platform.
typedef long intptr_t;
typedef unsigned long uintptr_t;
typedef long scalar_t__; // Either arithmetic or pointer type.
/* By default, we understand bool (as a convenience). */
typedef int bool;
#define false 0
#define true 1

/* Forward declarations */

/* Type definitions */

/* Variables and functions */
int atoi(char *);
int fib(int, int);
int /*<<< orphan*/ printf(char *, ...);
int main(int argc, char **argv) {
  int n;
  if (argc < 2) {
    printf("usage: fib n\n"
           "Compute nth Fibonacci number\n");
    return 1;
  }
  n = atoi(argv[1]);
  printf("fib(%d) = %d\n", n, fib(n, 2));
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
movl   $0x0,-0x4(%rbp)
mov    %edi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
cmpl   $0x2,-0x8(%rbp)
jge    116a <main+0x3a>
lea    0xea9(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
movl   $0x1,-0x4(%rbp)
jmp    11a7 <main+0x77>
mov    -0x10(%rbp),%rax
mov    0x8(%rax),%rdi
call   1050 <atoi@plt>
mov    %eax,-0x14(%rbp)
mov    -0x14(%rbp),%eax
mov    %eax,-0x18(%rbp)
mov    -0x14(%rbp),%edi
mov    $0x2,%esi
call   1040 <fib@plt>
mov    -0x18(%rbp),%esi
mov    %eax,%edx
lea    0xe92(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
movl   $0x0,-0x4(%rbp)
mov    -0x4(%rbp),%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rbp
push   %rbx
push   %rax
cmp    $0x1,%edi
jg     115b <main+0x1b>
lea    0xebf(%rip),%rdi
call   1030 <puts@plt>
mov    $0x1,%ebx
jmp    1186 <main+0x46>
mov    0x8(%rsi),%rdi
call   1060 <atoi@plt>
mov    %eax,%ebp
mov    %eax,%edi
mov    $0x2,%esi
call   1050 <fib@plt>
lea    0xe87(%rip),%rdi
xor    %ebx,%ebx
mov    %ebp,%esi
mov    %eax,%edx
xor    %eax,%eax
call   1040 <printf@plt>
mov    %ebx,%eax
add    $0x8,%rsp
pop    %rbx
pop    %rbp
ret

LLVM IR (-O0):
@.str = [43 x i8] c"usage: fib n\0ACompute nth Fibonacci number\0A\00"
@.str.1 = [14 x i8] c"fib(%d) = %d\0A\00"
define i32 @main(i32 %0, i8** %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca i8**
%6 = alloca i32
store i32 0, i32* %3
store i32 %0, i32* %4
store i8** %1, i8*** %5
%7 = load i32, i32* %4
%8 = icmp slt i32 %7, 2
br i1 %8, label %9, label %11
9: ; preds = %2
%10 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([43 x i8], [43 x i8]* @.str, i64 0, i64 0))
store i32 1, i32* %3
br label %20
11: ; preds = %2
%12 = load i8**, i8*** %5
%13 = getelementptr inbounds i8*, i8** %12, i64 1
%14 = load i8*, i8** %13
%15 = call i32 @atoi(i8* %14)
store i32 %15, i32* %6
%16 = load i32, i32* %6
%17 = load i32, i32* %6
%18 = call i32 @fib(i32 %17, i32 2)
%19 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.1, i64 0, i64 0), i32 %16, i32 %18)
store i32 0, i32* %3
br label %20
20: ; preds = %11, %9
%21 = load i32, i32* %3
ret i32 %21
}

LLVM IR (-O2):
@.str.1 = [14 x i8] c"fib(%d) = %d\0A\00"
@str = [42 x i8] c"usage: fib n\0ACompute nth Fibonacci number\00"
define i32 @main(i32 %0, i8** nocapture %1) {
%3 = icmp slt i32 %0, 2
br i1 %3, label %4, label %6
4: ; preds = %2
%5 = tail call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([42 x i8], [42 x i8]* @str, i64 0, i64 0))
br label %12
6: ; preds = %2
%7 = getelementptr inbounds i8*, i8** %1, i64 1
%8 = load i8*, i8** %7
%9 = tail call i32 @atoi(i8* %8)
%10 = tail call i32 @fib(i32 %9, i32 2)
%11 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([14 x i8], [14 x i8]* @.str.1, i64 0, i64 0), i32 %9, i32 %10)
br label %12
12: ; preds = %6, %4
%13 = phi i32 [ 1, %4 ], [ 0, %6 ]
ret i32 %13
}