#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 show_bytes(const void *data, size_t size) {
  const unsigned char *block = (const unsigned char *)data;
  for (size_t i = 0; i < size; ++i) {
    printf("%.2x ", *block++);
  }
  printf("\n");
}


x86 assembly (clang, -O0):
<show_bytes>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    -0x8(%rbp),%rax
mov    %rax,-0x18(%rbp)
movq   $0x0,-0x20(%rbp)
mov    -0x20(%rbp),%rax
cmp    -0x10(%rbp),%rax
jae    116f <show_bytes+0x5f>
mov    -0x18(%rbp),%rax
mov    %rax,%rcx
add    $0x1,%rcx
mov    %rcx,-0x18(%rbp)
movzbl (%rax),%esi
lea    0xea9(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
mov    -0x20(%rbp),%rax
add    $0x1,%rax
mov    %rax,-0x20(%rbp)
jmp    1130 <show_bytes+0x20>
lea    0xe90(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<show_bytes>:
push   %r15
push   %r14
push   %r12
push   %rbx
push   %rax
test   %rsi,%rsi
je     1158 <show_bytes+0x38>
mov    %rsi,%r12
mov    %rdi,%r14
lea    0xec6(%rip),%r15
xor    %ebx,%ebx
nopl   0x0(%rax)
movzbl (%r14,%rbx,1),%esi
mov    %r15,%rdi
xor    %eax,%eax
call   1040 <printf@plt>
add    $0x1,%rbx
cmp    %rbx,%r12
jne    1140 <show_bytes+0x20>
mov    $0xa,%edi
add    $0x8,%rsp
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
jmp    1030 <putchar@plt>

LLVM IR (-O0):
@.str = [6 x i8] c"%.2x \00"
@.str.1 = [2 x i8] c"\0A\00"
define void @show_bytes(i8* %0, i64 %1) {
%3 = alloca i8*
%4 = alloca i64
%5 = alloca i8*
%6 = alloca i64
store i8* %0, i8** %3
store i64 %1, i64* %4
%7 = load i8*, i8** %3
store i8* %7, i8** %5
store i64 0, i64* %6
br label %8
8: ; preds = %18, %2
%9 = load i64, i64* %6
%10 = load i64, i64* %4
%11 = icmp ult i64 %9, %10
br i1 %11, label %12, label %21
12: ; preds = %8
%13 = load i8*, i8** %5
%14 = getelementptr inbounds i8, i8* %13, i32 1
store i8* %14, i8** %5
%15 = load i8, i8* %13
%16 = zext i8 %15 to i32
%17 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([6 x i8], [6 x i8]* @.str, i64 0, i64 0), i32 %16)
br label %18
18: ; preds = %12
%19 = load i64, i64* %6
%20 = add i64 %19, 1
store i64 %20, i64* %6
br label %8
21: ; preds = %8
%22 = 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 = [6 x i8] c"%.2x \00"
define void @show_bytes(i8* nocapture %0, i64 %1) {
%3 = icmp eq i64 %1, 0
br i1 %3, label %4, label %6
4: ; preds = %6, %2
%5 = tail call i32 @putchar(i32 10)
ret void
6: ; preds = %2, %6
%7 = phi i64 [ %13, %6 ], [ 0, %2 ]
%8 = phi i8* [ %9, %6 ], [ %0, %2 ]
%9 = getelementptr inbounds i8, i8* %8, i64 1
%10 = load i8, i8* %8
%11 = zext i8 %10 to i32
%12 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([6 x i8], [6 x i8]* @.str, i64 0, i64 0), i32 %11)
%13 = add nuw i64 %7, 1
%14 = icmp eq i64 %13, %1
br i1 %14, label %4, label %6
}