[PATCH] Make alias_sets_conflict_p less conservative

[Paolo Bonzini]

> Yes, char is assigned alias set zero.  And this is correct.
> 
>   char a[4];
>   int *p;
> 
> an access through *p conflicts with a.  (note there is no char * involved
> here)

Would it be considered a good cleanup to assign it a different alias 
set, and make C char* a TYPE_REF_CAN_ALIAS_ALL variant?  Other languages 
may not have this behavior.

Paolo