#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*/ assert(char *);
char *c_malloc(long);
long strlen(char *);
char tolower(char);
char *str_tolower(char *str) {
  assert(str);
  long lenght = strlen(str);
  char *result = c_malloc(lenght * sizeof(char));
  for (int i = 0; i < lenght; i++)
    result[i] = tolower(str[i]);
  return result;
}


x86 assembly (clang, -O0):
<str_tolower>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    -0x8(%rbp),%rdi
call   1050 <assert@plt>
mov    -0x8(%rbp),%rdi
call   1030 <strlen@plt>
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rdi
shl    $0x0,%rdi
call   1040 <c_malloc@plt>
mov    %rax,-0x18(%rbp)
movl   $0x0,-0x1c(%rbp)
movslq -0x1c(%rbp),%rax
cmp    -0x10(%rbp),%rax
jge    11b4 <str_tolower+0x74>
mov    -0x8(%rbp),%rax
movslq -0x1c(%rbp),%rcx
movsbl (%rax,%rcx,1),%edi
call   1060 <tolower@plt>
mov    %al,%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    117a <str_tolower+0x3a>
mov    -0x18(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<str_tolower>:
push   %r15
push   %r14
push   %r12
push   %rbx
push   %rax
mov    %rdi,%r14
call   1050 <assert@plt>
mov    %r14,%rdi
call   1030 <strlen@plt>
mov    %rax,%r15
mov    %rax,%rdi
call   1040 <c_malloc@plt>
mov    %rax,%r12
test   %r15,%r15
jle    1187 <str_tolower+0x47>
xor    %ebx,%ebx
nopl   (%rax)
movsbl (%r14,%rbx,1),%edi
call   1060 <tolower@plt>
mov    %al,(%r12,%rbx,1)
add    $0x1,%rbx
cmp    %rbx,%r15
jne    1170 <str_tolower+0x30>
mov    %r12,%rax
add    $0x8,%rsp
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
ret

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

LLVM IR (-O2):
define i8* @str_tolower(i8* %0) {
%2 = tail call i32 @assert(i8* %0)
%3 = tail call i64 @strlen(i8* dereferenceable(1) %0)
%4 = tail call i8* @c_malloc(i64 %3)
%5 = icmp sgt i64 %3, 0
br i1 %5, label %7, label %6
6: ; preds = %7, %1
ret i8* %4
7: ; preds = %1, %7
%8 = phi i64 [ %13, %7 ], [ 0, %1 ]
%9 = getelementptr inbounds i8, i8* %0, i64 %8
%10 = load i8, i8* %9
%11 = tail call signext i8 @tolower(i8 signext %10)
%12 = getelementptr inbounds i8, i8* %4, i64 %8
store i8 %11, i8* %12
%13 = add nuw nsw i64 %8, 1
%14 = icmp eq i64 %13, %3
br i1 %14, label %6, label %7
}