void memshl(register int *pA) {
  register int *pB = pA + 16;
  *pA++ = *pB++;
  *pA++ = *pB++;
  *pA++ = *pB++;
  *pA++ = *pB++;
  *pA++ = *pB++;
  *pA++ = *pB++;
  *pA++ = *pB++;
  *pA = *pB;
}


x86 assembly (clang, -O0):
<memshl>:
push   %rbp
mov    %rsp,%rbp
mov    %rdi,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x40,%rax
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rax
mov    %rax,%rcx
add    $0x4,%rcx
mov    %rcx,-0x10(%rbp)
mov    (%rax),%ecx
mov    -0x8(%rbp),%rax
mov    %rax,%rdx
add    $0x4,%rdx
mov    %rdx,-0x8(%rbp)
mov    %ecx,(%rax)
mov    -0x10(%rbp),%rax
mov    %rax,%rcx
add    $0x4,%rcx
mov    %rcx,-0x10(%rbp)
mov    (%rax),%ecx
mov    -0x8(%rbp),%rax
mov    %rax,%rdx
add    $0x4,%rdx
mov    %rdx,-0x8(%rbp)
mov    %ecx,(%rax)
mov    -0x10(%rbp),%rax
mov    %rax,%rcx
add    $0x4,%rcx
mov    %rcx,-0x10(%rbp)
mov    (%rax),%ecx
mov    -0x8(%rbp),%rax
mov    %rax,%rdx
add    $0x4,%rdx
mov    %rdx,-0x8(%rbp)
mov    %ecx,(%rax)
mov    -0x10(%rbp),%rax
mov    %rax,%rcx
add    $0x4,%rcx
mov    %rcx,-0x10(%rbp)
mov    (%rax),%ecx
mov    -0x8(%rbp),%rax
mov    %rax,%rdx
add    $0x4,%rdx
mov    %rdx,-0x8(%rbp)
mov    %ecx,(%rax)
mov    -0x10(%rbp),%rax
mov    %rax,%rcx
add    $0x4,%rcx
mov    %rcx,-0x10(%rbp)
mov    (%rax),%ecx
mov    -0x8(%rbp),%rax
mov    %rax,%rdx
add    $0x4,%rdx
mov    %rdx,-0x8(%rbp)
mov    %ecx,(%rax)
mov    -0x10(%rbp),%rax
mov    %rax,%rcx
add    $0x4,%rcx
mov    %rcx,-0x10(%rbp)
mov    (%rax),%ecx
mov    -0x8(%rbp),%rax
mov    %rax,%rdx
add    $0x4,%rdx
mov    %rdx,-0x8(%rbp)
mov    %ecx,(%rax)
mov    -0x10(%rbp),%rax
mov    %rax,%rcx
add    $0x4,%rcx
mov    %rcx,-0x10(%rbp)
mov    (%rax),%ecx
mov    -0x8(%rbp),%rax
mov    %rax,%rdx
add    $0x4,%rdx
mov    %rdx,-0x8(%rbp)
mov    %ecx,(%rax)
mov    -0x10(%rbp),%rax
mov    (%rax),%ecx
mov    -0x8(%rbp),%rax
mov    %ecx,(%rax)
pop    %rbp
ret

x86 assembly (clang, -O2):
<memshl>:
movups 0x40(%rdi),%xmm0
movups 0x50(%rdi),%xmm1
movups %xmm0,(%rdi)
movups %xmm1,0x10(%rdi)
ret

LLVM IR (-O0):
define void @memshl(i32* %0) {
%2 = alloca i32*
%3 = alloca i32*
store i32* %0, i32** %2
%4 = load i32*, i32** %2
%5 = getelementptr inbounds i32, i32* %4, i64 16
store i32* %5, i32** %3
%6 = load i32*, i32** %3
%7 = getelementptr inbounds i32, i32* %6, i32 1
store i32* %7, i32** %3
%8 = load i32, i32* %6
%9 = load i32*, i32** %2
%10 = getelementptr inbounds i32, i32* %9, i32 1
store i32* %10, i32** %2
store i32 %8, i32* %9
%11 = load i32*, i32** %3
%12 = getelementptr inbounds i32, i32* %11, i32 1
store i32* %12, i32** %3
%13 = load i32, i32* %11
%14 = load i32*, i32** %2
%15 = getelementptr inbounds i32, i32* %14, i32 1
store i32* %15, i32** %2
store i32 %13, i32* %14
%16 = load i32*, i32** %3
%17 = getelementptr inbounds i32, i32* %16, i32 1
store i32* %17, i32** %3
%18 = load i32, i32* %16
%19 = load i32*, i32** %2
%20 = getelementptr inbounds i32, i32* %19, i32 1
store i32* %20, i32** %2
store i32 %18, i32* %19
%21 = load i32*, i32** %3
%22 = getelementptr inbounds i32, i32* %21, i32 1
store i32* %22, i32** %3
%23 = load i32, i32* %21
%24 = load i32*, i32** %2
%25 = getelementptr inbounds i32, i32* %24, i32 1
store i32* %25, i32** %2
store i32 %23, i32* %24
%26 = load i32*, i32** %3
%27 = getelementptr inbounds i32, i32* %26, i32 1
store i32* %27, i32** %3
%28 = load i32, i32* %26
%29 = load i32*, i32** %2
%30 = getelementptr inbounds i32, i32* %29, i32 1
store i32* %30, i32** %2
store i32 %28, i32* %29
%31 = load i32*, i32** %3
%32 = getelementptr inbounds i32, i32* %31, i32 1
store i32* %32, i32** %3
%33 = load i32, i32* %31
%34 = load i32*, i32** %2
%35 = getelementptr inbounds i32, i32* %34, i32 1
store i32* %35, i32** %2
store i32 %33, i32* %34
%36 = load i32*, i32** %3
%37 = getelementptr inbounds i32, i32* %36, i32 1
store i32* %37, i32** %3
%38 = load i32, i32* %36
%39 = load i32*, i32** %2
%40 = getelementptr inbounds i32, i32* %39, i32 1
store i32* %40, i32** %2
store i32 %38, i32* %39
%41 = load i32*, i32** %3
%42 = load i32, i32* %41
%43 = load i32*, i32** %2
store i32 %42, i32* %43
ret void
}

LLVM IR (-O2):
define void @memshl(i32* nocapture %0) {
%2 = getelementptr inbounds i32, i32* %0, i64 16
%3 = getelementptr inbounds i32, i32* %0, i64 20
%4 = bitcast i32* %2 to <4 x i32>*
%5 = load <4 x i32>, <4 x i32>* %4
%6 = getelementptr inbounds i32, i32* %0, i64 4
%7 = bitcast i32* %0 to <4 x i32>*
store <4 x i32> %5, <4 x i32>* %7
%8 = bitcast i32* %3 to <4 x i32>*
%9 = load <4 x i32>, <4 x i32>* %8
%10 = bitcast i32* %6 to <4 x i32>*
store <4 x i32> %9, <4 x i32>* %10
ret void
}