#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*/ printf(char *, ...);
void printHex(unsigned char *buffer, int length) {
  int i = 0;
  for (i = 0; i < length; ++i) {
    printf("%2x ", buffer[i]);
    if (i % 16 == 0) {
      printf("\n");
    }
  }
  printf("\n");
}


x86 assembly (clang, -O0):
<printHex>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
mov    %rdi,-0x8(%rbp)
mov    %esi,-0xc(%rbp)
movl   $0x0,-0x10(%rbp)
movl   $0x0,-0x10(%rbp)
mov    -0x10(%rbp),%eax
cmp    -0xc(%rbp),%eax
jge    1188 <printHex+0x78>
mov    -0x8(%rbp),%rax
movslq -0x10(%rbp),%rcx
movzbl (%rax,%rcx,1),%esi
lea    0xeb4(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
mov    -0x10(%rbp),%eax
mov    $0x10,%ecx
cltd
idiv   %ecx
cmp    $0x0,%edx
jne    1175 <printHex+0x65>
lea    0xe97(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
jmp    117a <printHex+0x6a>
mov    -0x10(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x10(%rbp)
jmp    112d <printHex+0x1d>
lea    0xe76(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<printHex>:
push   %r15
push   %r14
push   %r12
push   %rbx
push   %rax
test   %esi,%esi
jle    1169 <printHex+0x49>
mov    %rdi,%r15
mov    %esi,%r12d
lea    0xec7(%rip),%r14
xor    %ebx,%ebx
jmp    1149 <printHex+0x29>
nopl   (%rax)
add    $0x1,%rbx
cmp    %rbx,%r12
je     1169 <printHex+0x49>
movzbl (%r15,%rbx,1),%esi
mov    %r14,%rdi
xor    %eax,%eax
call   1040 <printf@plt>
test   $0xf,%bl
jne    1140 <printHex+0x20>
mov    $0xa,%edi
call   1030 <putchar@plt>
jmp    1140 <printHex+0x20>
mov    $0xa,%edi
add    $0x8,%rsp
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
jmp    1030 <putchar@plt>

LLVM IR (-O0):
@.str = [5 x i8] c"%2x \00"
@.str.1 = [2 x i8] c"\0A\00"
define void @printHex(i8* %0, i32 %1) {
%3 = alloca i8*
%4 = alloca i32
%5 = alloca i32
store i8* %0, i8** %3
store i32 %1, i32* %4
store i32 0, i32* %5
store i32 0, i32* %5
br label %6
6: ; preds = %24, %2
%7 = load i32, i32* %5
%8 = load i32, i32* %4
%9 = icmp slt i32 %7, %8
br i1 %9, label %10, label %27
10: ; preds = %6
%11 = load i8*, i8** %3
%12 = load i32, i32* %5
%13 = sext i32 %12 to i64
%14 = getelementptr inbounds i8, i8* %11, i64 %13
%15 = load i8, i8* %14
%16 = zext i8 %15 to i32
%17 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i64 0, i64 0), i32 %16)
%18 = load i32, i32* %5
%19 = srem i32 %18, 16
%20 = icmp eq i32 %19, 0
br i1 %20, label %21, label %23
21: ; preds = %10
%22 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.1, i64 0, i64 0))
br label %23
23: ; preds = %21, %10
br label %24
24: ; preds = %23
%25 = load i32, i32* %5
%26 = add nsw i32 %25, 1
store i32 %26, i32* %5
br label %6
27: ; preds = %6
%28 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.1, i64 0, i64 0))
ret void
}

LLVM IR (-O2):
@.str = [5 x i8] c"%2x \00"
define void @printHex(i8* nocapture %0, i32 %1) {
%3 = icmp sgt i32 %1, 0
br i1 %3, label %4, label %19
4: ; preds = %2
%5 = zext i32 %1 to i64
br label %6
6: ; preds = %4, %16
%7 = phi i64 [ 0, %4 ], [ %17, %16 ]
%8 = getelementptr inbounds i8, i8* %0, i64 %7
%9 = load i8, i8* %8
%10 = zext i8 %9 to i32
%11 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([5 x i8], [5 x i8]* @.str, i64 0, i64 0), i32 %10)
%12 = and i64 %7, 15
%13 = icmp eq i64 %12, 0
br i1 %13, label %14, label %16
14: ; preds = %6
%15 = tail call i32 @putchar(i32 10)
br label %16
16: ; preds = %6, %14
%17 = add nuw nsw i64 %7, 1
%18 = icmp eq i64 %17, %5
br i1 %18, label %19, label %6
19: ; preds = %16, %2
%20 = tail call i32 @putchar(i32 10)
ret void
}