Re: Patch to fix gcc.c-torture/compile/20010102-1.c on IA64 HP-UX

[Jeff Law <law@redhat.com>]

David Edelsohn wrote:
> Jeff,
>
> The RTL is a pair of (high (symbol_ref)) and (lo_sum (reg) (symbol_ref)).
>   
Presumably at the point in question we're looking at the lo_sum insn, right?

> alias.c:find_base_value() has a special case for lo_sum:
>
>     case LO_SUM:
>       /* The standard form is (lo_sum reg sym) so look only at the
>          second operand.  */
>       return find_base_value (XEXP (src, 1));
>
> However, find_base_term() throws lo_sum in with PLUS and MINUS,
> which prefers the REG.  find_base_term() appears to expect that the
> symbol_ref from the HIGH will be recorded with the REG and picked
> up by the LO_SUM from that source.
>
> find_base_term() either could check for non-zero base before returning
> in the lo_sum/plus/minus case statement or could handle lo_sum
> explicitly, like find_base_value().
>   
I think my suggestion will accomplish the same thing -- and it makes 
logical sense too -- if we can't determine something from the pointer 
reg, then we look at other info, such as the symbol_ref within a lo_sum.


Jeff