Re: [PATCH] Fix PR70484, RTL DSE using wrong dependence check

[Bernd Schmidt]

On 04/01/2016 11:08 AM, Richard Biener wrote:
        {
!         if (canon_true_dependence (s_info->mem,
!                                    GET_MODE (s_info->mem),
!                                    s_info->mem_addr,
!                                    mem, mem_addr))
            {
              s_info->rhs = NULL;
              s_info->const_rhs = NULL;
--- 1609,1617 ----
           the value of store_info.  If it is, set the rhs to NULL to
           keep it from being used to remove a load.  */
        {
!         if (canon_output_dependence (s_info->mem, true,
!                                      mem, GET_MODE (mem),
!                                      mem_addr))
            {
              s_info->rhs = NULL;
              s_info->const_rhs = NULL;

I think the patch is ok, but there is a comment in that function which 
references canon_true_dependence; that should also be fixed up.

Isn't the testcase invalid though? I thought accesses through char * 
pointers bypass aliasing rules, but accessing a char array through int * 
and long * pointers doesn't?


Bernd