clang.s

	.text
	.file	"combine.c"
	.globl	evalexpr_0_0            # -- Begin function evalexpr_0_0
	.p2align	4, 0x90
	.type	evalexpr_0_0,@function
evalexpr_0_0:                           # @evalexpr_0_0
	.cfi_startproc
# %bb.0:
	movb	$0, (%rdi)
	movb	$1, (%rsi)
	movb	$0, 1(%rdi)
	movb	$1, 1(%rsi)
	movb	$0, 2(%rdi)
	movb	$1, 2(%rsi)
	movb	$0, 3(%rdi)
	movb	$1, 3(%rsi)
	movups	(%rcx), %xmm0
	movups	%xmm0, (%rdx)
	movb	$0, 4(%rdi)
	movb	$1, 4(%rsi)
	movl	16(%rcx), %eax
	movl	%eax, 16(%rdx)
	retq
.Lfunc_end0:
	.size	evalexpr_0_0, .Lfunc_end0-evalexpr_0_0
	.cfi_endproc
                                        # -- End function

	.ident	"clang version 8.0.0-svn340819-1 (trunk)"
	.section	".note.GNU-stack","",@progbits
	.addrsig

combine.c

#include <stdint.h>

void
evalexpr_0_0(uint8_t * restrict a, uint8_t * restrict b, uint32_t * restrict c, uint32_t * restrict s)
{
  a[0] = 0;
  b[0] = 1;
  c[0] = s[0];
  a[1] = 0;
  b[1] = 1;
  c[1] = s[1];
  a[2] = 0;
  b[2] = 1;
  c[2] = s[2];
  a[3] = 0;
  b[3] = 1;
  c[3] = s[3];
  a[4] = 0;
  b[4] = 1;
  c[4] = s[4];
}

gcc.s

	.file	"combine.c"
	.text
	.p2align 4,,15
	.globl	evalexpr_0_0
	.type	evalexpr_0_0, @function
evalexpr_0_0:
.LFB0:
	.cfi_startproc
	movdqu	(%rcx), %xmm0
	movl	16(%rcx), %eax
	movl	$0, (%rdi)
	movb	$0, 4(%rdi)
	movups	%xmm0, (%rdx)
	movl	$16843009, (%rsi)
	movb	$1, 4(%rsi)
	movl	%eax, 16(%rdx)
	ret
	.cfi_endproc
.LFE0:
	.size	evalexpr_0_0, .-evalexpr_0_0
	.ident	"GCC: (Debian 8.2.0-5) 8.2.0"
	.section	.note.GNU-stack,"",@progbits