#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 strlen(char *);
char *find(char *haystack, char needle) {
  int lenght = 0;
  int counter = 0;
  lenght = strlen(haystack);
  for (counter = 0; counter < lenght; counter++) {
    if (haystack[counter] == needle) {
      return &haystack[counter];
      break;
    }
  }
  return NULL;
}


x86 assembly (clang, -O0):
<find>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %sil,%al
mov    %rdi,-0x10(%rbp)
mov    %al,-0x11(%rbp)
movl   $0x0,-0x18(%rbp)
movl   $0x0,-0x1c(%rbp)
mov    -0x10(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,-0x18(%rbp)
movl   $0x0,-0x1c(%rbp)
mov    -0x1c(%rbp),%eax
cmp    -0x18(%rbp),%eax
jge    118e <find+0x7e>
mov    -0x10(%rbp),%rax
movslq -0x1c(%rbp),%rcx
movsbl (%rax,%rcx,1),%eax
movsbl -0x11(%rbp),%ecx
cmp    %ecx,%eax
jne    117b <find+0x6b>
mov    -0x10(%rbp),%rax
movslq -0x1c(%rbp),%rcx
add    %rcx,%rax
mov    %rax,-0x8(%rbp)
jmp    1196 <find+0x86>
jmp    1180 <find+0x70>
mov    -0x1c(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x1c(%rbp)
jmp    1143 <find+0x33>
movq   $0x0,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<find>:
push   %rbp
push   %rbx
push   %rax
mov    %esi,%ebp
mov    %rdi,%rbx
call   1030 <strlen@plt>
test   %eax,%eax
jle    113f <find+0x2f>
mov    %eax,%eax
cs nopw 0x0(%rax,%rax,1)
nopl   (%rax)
cmp    %bpl,(%rbx)
je     1141 <find+0x31>
add    $0x1,%rbx
add    $0xffffffffffffffff,%rax
jne    1130 <find+0x20>
xor    %ebx,%ebx
mov    %rbx,%rax
add    $0x8,%rsp
pop    %rbx
pop    %rbp
ret

LLVM IR (-O0):
define i8* @find(i8* %0, i8 signext %1) {
%3 = alloca i8*
%4 = alloca i8*
%5 = alloca i8
%6 = alloca i32
%7 = alloca i32
store i8* %0, i8** %4
store i8 %1, i8* %5
store i32 0, i32* %6
store i32 0, i32* %7
%8 = load i8*, i8** %4
%9 = call i32 @strlen(i8* %8)
store i32 %9, i32* %6
store i32 0, i32* %7
br label %10
10: ; preds = %30, %2
%11 = load i32, i32* %7
%12 = load i32, i32* %6
%13 = icmp slt i32 %11, %12
br i1 %13, label %14, label %33
14: ; preds = %10
%15 = load i8*, i8** %4
%16 = load i32, i32* %7
%17 = sext i32 %16 to i64
%18 = getelementptr inbounds i8, i8* %15, i64 %17
%19 = load i8, i8* %18
%20 = sext i8 %19 to i32
%21 = load i8, i8* %5
%22 = sext i8 %21 to i32
%23 = icmp eq i32 %20, %22
br i1 %23, label %24, label %29
24: ; preds = %14
%25 = load i8*, i8** %4
%26 = load i32, i32* %7
%27 = sext i32 %26 to i64
%28 = getelementptr inbounds i8, i8* %25, i64 %27
store i8* %28, i8** %3
br label %34
29: ; preds = %14
br label %30
30: ; preds = %29
%31 = load i32, i32* %7
%32 = add nsw i32 %31, 1
store i32 %32, i32* %7
br label %10
33: ; preds = %10
store i8* null, i8** %3
br label %34
34: ; preds = %33, %24
%35 = load i8*, i8** %3
ret i8* %35
}

LLVM IR (-O2):
define i8* @find(i8* %0, i8 signext %1) {
%3 = tail call i32 @strlen(i8* %0)
%4 = icmp sgt i32 %3, 0
br i1 %4, label %5, label %18
5: ; preds = %2
%6 = zext i32 %3 to i64
br label %7
7: ; preds = %5, %12
%8 = phi i64 [ 0, %5 ], [ %13, %12 ]
%9 = getelementptr inbounds i8, i8* %0, i64 %8
%10 = load i8, i8* %9
%11 = icmp eq i8 %10, %1
br i1 %11, label %15, label %12
12: ; preds = %7
%13 = add nuw nsw i64 %8, 1
%14 = icmp eq i64 %13, %6
br i1 %14, label %18, label %7
15: ; preds = %7
%16 = and i64 %8, 4294967295
%17 = getelementptr inbounds i8, i8* %0, i64 %16
br label %18
18: ; preds = %12, %2, %15
%19 = phi i8* [ %17, %15 ], [ null, %2 ], [ null, %12 ]
ret i8* %19
}