Re: [PATCH][ PR rtl-optimization/79286] Drop may_trap_p exception to testing dominance in update_equiv_regs

[Jeff Law <law at redhat dot com>]

On 04/28/2017 11:27 AM, Bernd Edlinger wrote:
> >
>
> Yes I agree, that is probably not worth it.  So I could try to remove
> the special handling of PIC+const and see what happens.
>
> However the SYMBOL_REF_FUNCTION_P is another story, that part I would
> like to keep: It happens quite often, already w/o -fpic that call
> statements are using SYMBOL_REFs to ordinary (not weak) function
> symbols, and may_trap returns 1 for these call statements wihch is IMHO
> wrong.
Hmm, thinking more about this, wasn't the original case a PIC referrence 
for something like &x[BIGNUM].

Perhaps we could consider a PIC reference without other arithmetic as 
safe.  That would likely pick up the SYMBOL_REF_FUNCTION_P case you want 
as well good deal many more PIC references as non-trapping.

Jeff