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Re: PATCH: RFA reload.c patch
> This patch doesn't make any sense to me. If you search for
> reg_equiv_memory_loc at the top of reload1.c, you will find a comment
> that says it may not be a valid MEM, and that it goes into either
> reg_equiv_mem or reg_equiv_address depending on whether it is valid.
> If you look about a hundred lines after the point that you patched, you
> will see code that does exactly what the comment says. It passes
> reg_equiv_memory_loc through strict_memory_address_p, and puts it in
> reg_equiv_mem if valid, in reg_equiv_address if it looks like an address
> that reload can fix, and clears it otherwise.
I see where you're talking about now.
> So your patch that clears it earlier on if it doesn't pass
> memory_address_p doesn't make any sense.
I think I can see this now. However, a couple of things: 1) we check
this up above where I did as well, and 2) we end up using the invalid
address later on in reload.
> Are you sure you aren't trying to cover up a bug in the frv port? That
> what it looks like to me.
Pretty sure. I'll explain what's going on here.
> You didn't provide a testcase, and apparently can't because you can't
> reproduce this in FSF sources, which makes this even more suspect.
Oh I probably could, if I had the new development work we're doing. The
reason that I can't provide the testcase is that it may be encumbered
because it's part of a proprietary conformance testsuite.
> What later pass is assuming that addresses in reg_equiv_memory_loc are
We start off with:
(set (reg xx)
(mem:SF (reg yy)))
with a REG_EQUIV on yy to (const_double:SF ....)
and find_reloads_toplev checks reg_equiv_address and
reg_equiv_memory_loc at that location.
Since your mail I did some checking and it looks that reg_equiv_address
isn't verified using strict_address_p, only reg_equiv_mem is.
Anyhow, we then replace
(mem:SF (reg yy))
(mem:SF (symbol_ref/u ..LC0))
later in find_reloads_address after a lot of if/else if conditions we
notice that the address isn't valid and send it down through
find_reloads_address_part which immediately tries to force the it via
force_const_mem and since it's a symbol_ref we don't allow that to
happen and end up returning null and segfaulting there.
About the only other thing I can think of is replacing the use of
reg_equiv_address with reg_equiv_mem which seems like it might work, but
I'm not really as sure there.
Eric Christopher <firstname.lastname@example.org>