#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*/ printf(char *, ...);
int strStr(char *, char *);
int main(void) {
  char *haystack = "";
  char *needle = "a";
  int index = strStr(haystack, needle);
  if (index != -1) {
    printf("index of needle in haystack is : %d\n", index);
  } else {
    printf("Not find!\n");
  }
  return 0;
}


x86 assembly (clang, -O0):
<main>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
movl   $0x0,-0x4(%rbp)
lea    0xefb(%rip),%rax
mov    %rax,-0x10(%rbp)
lea    0xebf(%rip),%rax
mov    %rax,-0x18(%rbp)
mov    -0x10(%rbp),%rdi
mov    -0x18(%rbp),%rsi
call   1040 <strStr@plt>
mov    %eax,-0x1c(%rbp)
cmpl   $0xffffffff,-0x1c(%rbp)
je     1175 <main+0x55>
mov    -0x1c(%rbp),%esi
lea    0xe99(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
jmp    1183 <main+0x63>
lea    0xeab(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<main>:
push   %rax
lea    0xeee(%rip),%rdi
lea    0xec1(%rip),%rsi
call   1050 <strStr@plt>
cmp    $0xffffffff,%eax
je     115b <main+0x2b>
lea    0xeb2(%rip),%rdi
mov    %eax,%esi
xor    %eax,%eax
call   1040 <printf@plt>
jmp    1167 <main+0x37>
lea    0xec5(%rip),%rdi
call   1030 <puts@plt>
xor    %eax,%eax
pop    %rcx
ret

LLVM IR (-O0):
@.str = [1 x i8] zeroinitializer
@.str.1 = [2 x i8] c"a\00"
@.str.2 = [37 x i8] c"index of needle in haystack is : %d\0A\00"
@.str.3 = [11 x i8] c"Not find!\0A\00"
define i32 @main() {
%1 = alloca i32
%2 = alloca i8*
%3 = alloca i8*
%4 = alloca i32
store i32 0, i32* %1
store i8* getelementptr inbounds ([1 x i8], [1 x i8]* @.str, i64 0, i64 0), i8** %2
store i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.1, i64 0, i64 0), i8** %3
%5 = load i8*, i8** %2
%6 = load i8*, i8** %3
%7 = call i32 @strStr(i8* %5, i8* %6)
store i32 %7, i32* %4
%8 = load i32, i32* %4
%9 = icmp ne i32 %8, -1
br i1 %9, label %10, label %13
10: ; preds = %0
%11 = load i32, i32* %4
%12 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([37 x i8], [37 x i8]* @.str.2, i64 0, i64 0), i32 %11)
br label %15
13: ; preds = %0
%14 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([11 x i8], [11 x i8]* @.str.3, i64 0, i64 0))
br label %15
15: ; preds = %13, %10
ret i32 0
}

LLVM IR (-O2):
@.str = [1 x i8] zeroinitializer
@.str.1 = [2 x i8] c"a\00"
@.str.2 = [37 x i8] c"index of needle in haystack is : %d\0A\00"
@str = [10 x i8] c"Not find!\00"
define i32 @main() {
%1 = tail call i32 @strStr(i8* getelementptr inbounds ([1 x i8], [1 x i8]* @.str, i64 0, i64 0), i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.1, i64 0, i64 0))
%2 = icmp eq i32 %1, -1
br i1 %2, label %5, label %3
3: ; preds = %0
%4 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([37 x i8], [37 x i8]* @.str.2, i64 0, i64 0), i32 %1)
br label %7
5: ; preds = %0
%6 = tail call i32 @puts(i8* dereferenceable(1) getelementptr inbounds ([10 x i8], [10 x i8]* @str, i64 0, i64 0))
br label %7
7: ; preds = %5, %3
ret i32 0
}