#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 tolower(char);
void to_lower_case(char word_lower[], int wordlen, char *word) {
  for (int i = 0; i < wordlen; i++) {
    word_lower[i] = tolower(word[i]);
  }
  word_lower[wordlen] = '\0';
}


x86 assembly (clang, -O0):
<to_lower_case>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    %esi,-0xc(%rbp)
mov    %rdx,-0x18(%rbp)
movl   $0x0,-0x1c(%rbp)
mov    -0x1c(%rbp),%eax
cmp    -0xc(%rbp),%eax
jge    1162 <to_lower_case+0x52>
mov    -0x18(%rbp),%rax
movslq -0x1c(%rbp),%rcx
movsbl (%rax,%rcx,1),%edi
call   1030 <tolower@plt>
mov    %al,%dl
mov    -0x8(%rbp),%rax
movslq -0x1c(%rbp),%rcx
mov    %dl,(%rax,%rcx,1)
mov    -0x1c(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x1c(%rbp)
jmp    112a <to_lower_case+0x1a>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<to_lower_case>:
push   %rbp
push   %r15
push   %r14
push   %r12
push   %rbx
mov    %esi,%r14d
mov    %rdi,%r12
test   %esi,%esi
jle    1147 <to_lower_case+0x37>
mov    %rdx,%r15
mov    %r14d,%ebp
xor    %ebx,%ebx
nopw   0x0(%rax,%rax,1)
movsbl (%r15,%rbx,1),%edi
call   1030 <tolower@plt>
mov    %al,(%r12,%rbx,1)
add    $0x1,%rbx
cmp    %rbx,%rbp
jne    1130 <to_lower_case+0x20>
movslq %r14d,%rax
movb   $0x0,(%r12,%rax,1)
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
pop    %rbp
ret

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

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