CSAPP 5.6 Eliminating Unneeded Memory References

1	. L17:				loop:
2	   vmovsd (%rbx), %xmm0		  Read product from dest
3	   vmulsd (%rdx), %xmm0, %xmm0	  Multiply product by data[i]
4	   vmovsd %xmm0, (%rbx)		  Store product at dest
5	   addq $8, %rdx		  Increment data+i
6	   cmpq %rax, %rdx		  Compare to data+length
7	   jne .L17			  If !=, goto loop

1	/* Accumulate result in local variable */
2	void combine4(vec_ptr v, data_t *dest)
3	{
4		long i;
5		long length = vec_length(v);
6		data_t *data = get_vec_start(v);
7		data_t acc = IDENT;
8	
9		for (i = 0; i < length; i++) {
10			acc = acc OP data[i];
11		}
12		*dest = acc;
13	}