#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 *);
void tolower(char *str) {
  int x;
  for (x = 0; x < strlen(str); x++) {
    if (str[x] >= 'Z' && str[x] <= 'A') {
      str[x] = str[x] + 32;
    }
  }
}


x86 assembly (clang, -O0):
<tolower>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
mov    %rdi,-0x8(%rbp)
movl   $0x0,-0xc(%rbp)
mov    -0xc(%rbp),%eax
mov    %eax,-0x10(%rbp)
mov    -0x8(%rbp),%rdi
call   1030 <strlen@plt>
mov    %eax,%ecx
mov    -0x10(%rbp),%eax
cmp    %ecx,%eax
jge    1198 <tolower+0x88>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
movsbl (%rax,%rcx,1),%eax
cmp    $0x5a,%eax
jl     1185 <tolower+0x75>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
movsbl (%rax,%rcx,1),%eax
cmp    $0x41,%eax
jg     1185 <tolower+0x75>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
movsbl (%rax,%rcx,1),%eax
add    $0x20,%eax
mov    %al,%dl
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
mov    %dl,(%rax,%rcx,1)
jmp    118a <tolower+0x7a>
mov    -0xc(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0xc(%rbp)
jmp    1123 <tolower+0x13>
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<tolower>:
push   %rbp
push   %rbx
push   %rax
mov    %rdi,%rbx
mov    $0xffffffff,%ebp
nopl   0x0(%rax,%rax,1)
mov    %rbx,%rdi
call   1030 <strlen@plt>
add    $0x1,%ebp
cmp    %eax,%ebp
jl     1120 <tolower+0x10>
add    $0x8,%rsp
pop    %rbx
pop    %rbp
ret

LLVM IR (-O0):
define void @tolower(i8* %0) {
%2 = alloca i8*
%3 = alloca i32
store i8* %0, i8** %2
store i32 0, i32* %3
br label %4
4: ; preds = %39, %1
%5 = load i32, i32* %3
%6 = load i8*, i8** %2
%7 = call i32 @strlen(i8* %6)
%8 = icmp slt i32 %5, %7
br i1 %8, label %9, label %42
9: ; preds = %4
%10 = load i8*, i8** %2
%11 = load i32, i32* %3
%12 = sext i32 %11 to i64
%13 = getelementptr inbounds i8, i8* %10, i64 %12
%14 = load i8, i8* %13
%15 = sext i8 %14 to i32
%16 = icmp sge i32 %15, 90
br i1 %16, label %17, label %38
17: ; preds = %9
%18 = load i8*, i8** %2
%19 = load i32, i32* %3
%20 = sext i32 %19 to i64
%21 = getelementptr inbounds i8, i8* %18, i64 %20
%22 = load i8, i8* %21
%23 = sext i8 %22 to i32
%24 = icmp sle i32 %23, 65
br i1 %24, label %25, label %38
25: ; preds = %17
%26 = load i8*, i8** %2
%27 = load i32, i32* %3
%28 = sext i32 %27 to i64
%29 = getelementptr inbounds i8, i8* %26, i64 %28
%30 = load i8, i8* %29
%31 = sext i8 %30 to i32
%32 = add nsw i32 %31, 32
%33 = trunc i32 %32 to i8
%34 = load i8*, i8** %2
%35 = load i32, i32* %3
%36 = sext i32 %35 to i64
%37 = getelementptr inbounds i8, i8* %34, i64 %36
store i8 %33, i8* %37
br label %38
38: ; preds = %25, %17, %9
br label %39
39: ; preds = %38
%40 = load i32, i32* %3
%41 = add nsw i32 %40, 1
store i32 %41, i32* %3
br label %4
42: ; preds = %4
ret void
}

LLVM IR (-O2):
define void @tolower(i8* %0) {
br label %2
2: ; preds = %2, %1
%3 = phi i32 [ 0, %1 ], [ %6, %2 ]
%4 = tail call i32 @strlen(i8* %0)
%5 = icmp slt i32 %3, %4
%6 = add nuw nsw i32 %3, 1
br i1 %5, label %2, label %7
7: ; preds = %2
ret void
}