#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 */
char *malloc(int);
char *copy_string(char *string) {
  int length = 0;
  while (string[length])
    length++;
  char *result = malloc(sizeof(char) * (length + 1));
  result[length] = 0;
  int i;
  for (i = 0; i < length; i++)
    result[i] = string[i];
  return result;
}


x86 assembly (clang, -O0):
<copy_string>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
movl   $0x0,-0xc(%rbp)
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
cmpb   $0x0,(%rax,%rcx,1)
je     1143 <copy_string+0x33>
mov    -0xc(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0xc(%rbp)
jmp    1123 <copy_string+0x13>
mov    -0xc(%rbp),%eax
add    $0x1,%eax
cltq
shl    $0x0,%rax
mov    %eax,%edi
call   1030 <malloc@plt>
mov    %rax,-0x18(%rbp)
mov    -0x18(%rbp),%rax
movslq -0xc(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
movl   $0x0,-0x1c(%rbp)
mov    -0x1c(%rbp),%eax
cmp    -0xc(%rbp),%eax
jge    119d <copy_string+0x8d>
mov    -0x8(%rbp),%rax
movslq -0x1c(%rbp),%rcx
mov    (%rax,%rcx,1),%dl
mov    -0x18(%rbp),%rax
movslq -0x1c(%rbp),%rcx
mov    %dl,(%rax,%rcx,1)
mov    -0x1c(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x1c(%rbp)
jmp    116d <copy_string+0x5d>
mov    -0x18(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<copy_string>:
push   %r15
push   %r14
push   %r12
push   %rbx
push   %rax
mov    %rdi,%r14
xor    %ebx,%ebx
nopl   (%rax)
cmpb   $0x0,(%r14,%rbx,1)
lea    0x1(%rbx),%rbx
jne    1130 <copy_string+0x10>
lea    -0x1(%rbx),%r15d
mov    %ebx,%edi
call   1040 <malloc@plt>
mov    %rax,%r12
movb   $0x0,(%rax,%r15,1)
cmp    $0x1,%ebx
je     1161 <copy_string+0x41>
mov    %r12,%rdi
mov    %r14,%rsi
mov    %r15,%rdx
call   1030 <memcpy@plt>
mov    %r12,%rax
add    $0x8,%rsp
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define i8* @copy_string(i8* %0) {
%2 = alloca i8*
%3 = alloca i32
%4 = alloca i8*
%5 = alloca i32
store i8* %0, i8** %2
store i32 0, i32* %3
br label %6
6: ; preds = %13, %1
%7 = load i8*, i8** %2
%8 = load i32, i32* %3
%9 = sext i32 %8 to i64
%10 = getelementptr inbounds i8, i8* %7, i64 %9
%11 = load i8, i8* %10
%12 = icmp ne i8 %11, 0
br i1 %12, label %13, label %16
13: ; preds = %6
%14 = load i32, i32* %3
%15 = add nsw i32 %14, 1
store i32 %15, i32* %3
br label %6
16: ; preds = %6
%17 = load i32, i32* %3
%18 = add nsw i32 %17, 1
%19 = sext i32 %18 to i64
%20 = mul i64 1, %19
%21 = trunc i64 %20 to i32
%22 = call i8* @malloc(i32 %21)
store i8* %22, i8** %4
%23 = load i8*, i8** %4
%24 = load i32, i32* %3
%25 = sext i32 %24 to i64
%26 = getelementptr inbounds i8, i8* %23, i64 %25
store i8 0, i8* %26
store i32 0, i32* %5
br label %27
27: ; preds = %41, %16
%28 = load i32, i32* %5
%29 = load i32, i32* %3
%30 = icmp slt i32 %28, %29
br i1 %30, label %31, label %44
31: ; preds = %27
%32 = load i8*, i8** %2
%33 = load i32, i32* %5
%34 = sext i32 %33 to i64
%35 = getelementptr inbounds i8, i8* %32, i64 %34
%36 = load i8, i8* %35
%37 = load i8*, i8** %4
%38 = load i32, i32* %5
%39 = sext i32 %38 to i64
%40 = getelementptr inbounds i8, i8* %37, i64 %39
store i8 %36, i8* %40
br label %41
41: ; preds = %31
%42 = load i32, i32* %5
%43 = add nsw i32 %42, 1
store i32 %43, i32* %5
br label %27
44: ; preds = %27
%45 = load i8*, i8** %4
ret i8* %45
}

LLVM IR (-O2):
define noalias i8* @copy_string(i8* nocapture %0) {
br label %2
2: ; preds = %2, %1
%3 = phi i64 [ %7, %2 ], [ 0, %1 ]
%4 = getelementptr inbounds i8, i8* %0, i64 %3
%5 = load i8, i8* %4
%6 = icmp eq i8 %5, 0
%7 = add nuw i64 %3, 1
br i1 %6, label %8, label %2
8: ; preds = %2
%9 = trunc i64 %3 to i32
%10 = and i64 %3, 4294967295
%11 = add nuw nsw i32 %9, 1
%12 = tail call i8* @malloc(i32 %11)
%13 = getelementptr inbounds i8, i8* %12, i64 %10
store i8 0, i8* %13
%14 = icmp eq i32 %9, 0
br i1 %14, label %16, label %15
15: ; preds = %8
br label %16
16: ; preds = %15, %8
ret i8* %12
}