#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 *get_buffer();
int /*<<< orphan*/ tolower(unsigned char);
char *st_lower(const char *s) {
  char *p, *cp;
  p = cp = get_buffer();
  while (*s)
    *cp++ = tolower((unsigned char)(*s++));
  *cp++ = '\0';
  return p;
}


x86 assembly (clang, -O0):
<st_lower>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    $0x0,%al
call   1040 <get_buffer@plt>
mov    %rax,-0x18(%rbp)
mov    %rax,-0x10(%rbp)
mov    -0x8(%rbp),%rax
cmpb   $0x0,(%rax)
je     1177 <st_lower+0x57>
mov    -0x8(%rbp),%rax
mov    %rax,%rcx
add    $0x1,%rcx
mov    %rcx,-0x8(%rbp)
movzbl (%rax),%edi
call   1030 <tolower@plt>
mov    %al,%cl
mov    -0x18(%rbp),%rax
mov    %rax,%rdx
add    $0x1,%rdx
mov    %rdx,-0x18(%rbp)
mov    %cl,(%rax)
jmp    113b <st_lower+0x1b>
mov    -0x18(%rbp),%rax
mov    %rax,%rcx
add    $0x1,%rcx
mov    %rcx,-0x18(%rbp)
movb   $0x0,(%rax)
mov    -0x10(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<st_lower>:
push   %r15
push   %r14
push   %rbx
mov    %rdi,%r15
xor    %eax,%eax
call   1040 <get_buffer@plt>
mov    %rax,%r14
mov    (%r15),%al
mov    %r14,%rbx
test   %al,%al
je     116a <st_lower+0x4a>
add    $0x1,%r15
mov    %r14,%rbx
cs nopw 0x0(%rax,%rax,1)
nopl   (%rax)
movzbl %al,%edi
call   1030 <tolower@plt>
mov    %al,(%rbx)
add    $0x1,%rbx
movzbl (%r15),%eax
add    $0x1,%r15
test   %al,%al
jne    1150 <st_lower+0x30>
movb   $0x0,(%rbx)
mov    %r14,%rax
pop    %rbx
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define i8* @st_lower(i8* %0) {
%2 = alloca i8*
%3 = alloca i8*
%4 = alloca i8*
store i8* %0, i8** %2
%5 = call i8* (...) @get_buffer()
store i8* %5, i8** %4
store i8* %5, i8** %3
br label %6
6: ; preds = %10, %1
%7 = load i8*, i8** %2
%8 = load i8, i8* %7
%9 = icmp ne i8 %8, 0
br i1 %9, label %10, label %18
10: ; preds = %6
%11 = load i8*, i8** %2
%12 = getelementptr inbounds i8, i8* %11, i32 1
store i8* %12, i8** %2
%13 = load i8, i8* %11
%14 = call i32 @tolower(i8 zeroext %13)
%15 = trunc i32 %14 to i8
%16 = load i8*, i8** %4
%17 = getelementptr inbounds i8, i8* %16, i32 1
store i8* %17, i8** %4
store i8 %15, i8* %16
br label %6
18: ; preds = %6
%19 = load i8*, i8** %4
%20 = getelementptr inbounds i8, i8* %19, i32 1
store i8* %20, i8** %4
store i8 0, i8* %19
%21 = load i8*, i8** %3
ret i8* %21
}

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