#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 /*<<< orphan*/ getchar();
int /*<<< orphan*/ printf(char *, ...);
int str_len(char *);
int str_len2(char *);
int str_len3(char *);
int main() {
  printf("length = %d\n", str_len("hello! world!"));
  printf("length = %d\n", str_len2("hello! world!"));
  printf("length = %d\n", str_len3("hello! world!"));
  printf("\nPress any key to end...");
  getchar();
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xea7(%rip),%rdi
call   1070 <str_len@plt>
mov    %eax,%esi
lea    0xe8c(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    0xe8b(%rip),%rdi
call   1030 <str_len2@plt>
mov    %eax,%esi
lea    0xe70(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    0xe6f(%rip),%rdi
call   1060 <str_len3@plt>
mov    %eax,%esi
lea    0xe54(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
lea    0xe61(%rip),%rdi
mov    $0x0,%al
call   1040 <printf@plt>
mov    $0x0,%al
call   1050 <getchar@plt>
xor    %eax,%eax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %r14
push   %rbx
push   %rax
lea    0xeb2(%rip),%r14
mov    %r14,%rdi
call   1070 <str_len@plt>
lea    0xe96(%rip),%rbx
mov    %rbx,%rdi
mov    %eax,%esi
xor    %eax,%eax
call   1040 <printf@plt>
mov    %r14,%rdi
call   1030 <str_len2@plt>
mov    %rbx,%rdi
mov    %eax,%esi
xor    %eax,%eax
call   1040 <printf@plt>
mov    %r14,%rdi
call   1060 <str_len3@plt>
mov    %rbx,%rdi
mov    %eax,%esi
xor    %eax,%eax
call   1040 <printf@plt>
lea    0xe76(%rip),%rdi
xor    %eax,%eax
call   1040 <printf@plt>
xor    %eax,%eax
call   1050 <getchar@plt>
xor    %eax,%eax
add    $0x8,%rsp
pop    %rbx
pop    %r14
ret

LLVM IR (-O0):
@.str = [13 x i8] c"length = %d\0A\00"
@.str.1 = [14 x i8] c"hello! world!\00"
@.str.2 = [25 x i8] c"\0APress any key to end...\00"
define i32 @main() {
%1 = alloca i32
store i32 0, i32* %1
%2 = call i32 @str_len(i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.1, i64 0, i64 0))
%3 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str, i64 0, i64 0), i32 %2)
%4 = call i32 @str_len2(i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.1, i64 0, i64 0))
%5 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str, i64 0, i64 0), i32 %4)
%6 = call i32 @str_len3(i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.1, i64 0, i64 0))
%7 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str, i64 0, i64 0), i32 %6)
%8 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([25 x i8], [25 x i8]* @.str.2, i64 0, i64 0))
%9 = call i32 (...) @getchar()
ret i32 0
}

LLVM IR (-O2):
@.str = [13 x i8] c"length = %d\0A\00"
@.str.1 = [14 x i8] c"hello! world!\00"
@.str.2 = [25 x i8] c"\0APress any key to end...\00"
define i32 @main() {
%1 = tail call i32 @str_len(i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.1, i64 0, i64 0))
%2 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([13 x i8], [13 x i8]* @.str, i64 0, i64 0), i32 %1)
%3 = tail call i32 @str_len2(i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.1, i64 0, i64 0))
%4 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([13 x i8], [13 x i8]* @.str, i64 0, i64 0), i32 %3)
%5 = tail call i32 @str_len3(i8* getelementptr inbounds ([14 x i8], [14 x i8]* @.str.1, i64 0, i64 0))
%6 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([13 x i8], [13 x i8]* @.str, i64 0, i64 0), i32 %5)
%7 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([25 x i8], [25 x i8]* @.str.2, i64 0, i64 0))
%8 = tail call i32 (...) @getchar()
ret i32 0
}