#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 */
scalar_t__ malloc(int);
int strlen(char const *);
char tolower(unsigned int);
char *strlower(const char *str) {
  char *buffer = (char *)malloc(strlen(str) + 1);
  for (int i = 0; i < strlen(str); ++i)
    buffer[i] = tolower((unsigned)str[i]);
  return buffer;
}


x86 assembly (clang, -O0):
<strlower>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    -0x8(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,%edi
add    $0x1,%edi
call   1050 <malloc@plt>
mov    %rax,-0x10(%rbp)
movl   $0x0,-0x14(%rbp)
mov    -0x14(%rbp),%eax
mov    %eax,-0x18(%rbp)
mov    -0x8(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,%ecx
mov    -0x18(%rbp),%eax
cmp    %ecx,%eax
jge    11a2 <strlower+0x72>
mov    -0x8(%rbp),%rax
movslq -0x14(%rbp),%rcx
movsbl (%rax,%rcx,1),%edi
call   1040 <tolower@plt>
mov    %al,%dl
mov    -0x10(%rbp),%rax
movslq -0x14(%rbp),%rcx
mov    %dl,(%rax,%rcx,1)
mov    -0x14(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x14(%rbp)
jmp    115a <strlower+0x2a>
mov    -0x10(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<strlower>:
push   %r15
push   %r14
push   %rbx
mov    %rdi,%r15
call   1030 <strlen@plt>
lea    0x1(%rax),%edi
call   1050 <malloc@plt>
mov    %rax,%r14
mov    %r15,%rdi
call   1030 <strlen@plt>
test   %eax,%eax
jle    1181 <strlower+0x51>
xor    %ebx,%ebx
cs nopw 0x0(%rax,%rax,1)
movsbl (%r15,%rbx,1),%edi
call   1040 <tolower@plt>
mov    %al,(%r14,%rbx,1)
add    $0x1,%rbx
mov    %r15,%rdi
call   1030 <strlen@plt>
cltq
cmp    %rax,%rbx
jl     1160 <strlower+0x30>
mov    %r14,%rax
pop    %rbx
pop    %r14
pop    %r15
ret

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

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