From: Richard Biener <rguenther@suse.de>
To: Jakub Jelinek <jakub@redhat.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] Create less TARGET_MEM_REFs
Date: Wed, 18 Jun 2014 10:31:00 -0000 [thread overview]
Message-ID: <alpine.LSU.2.11.1406181221370.29270@zhemvz.fhfr.qr> (raw)
In-Reply-To: <20140618100403.GK31640@tucnak.redhat.com>
On Wed, 18 Jun 2014, Jakub Jelinek wrote:
> On Wed, Jun 18, 2014 at 11:56:01AM +0200, Richard Biener wrote:
> >
> > I just figured that we create &TARGET_MEM_REF [base: a_4, offset: 0]
> > from within IVOPTs. That pessimizes further passes unnecessarily.
> >
> > Bootstrap and regtest running on x86_64-unknown-linux-gnu.
>
> Isn't that against the comment above it?
> ??? As IVOPTs does not follow restrictions to where the base
> pointer may point to create a MEM_REF only if we know that
> base is valid.
> Perhaps it is fine only if addr->offset is integer_zerop?
Oh .... yeah, I guess so. Damn IVOPTs ... (though I wonder what's
the difference with MEM[&foo, -4B] then, which we don't catch
either). That said, I'm not sure if it really fixes anything
not allowing MEM_REFs in all cases.
I've found a different workaround for the issue I was facing so
I'm dropping this patch instead.
Richard.
> > 2014-06-18 Richard Biener <rguenther@suse.de>
> >
> > * tree-ssa-address.c (create_mem_ref_raw): Use proper predicate
> > to catch all valid MEM_REF pointer operands.
> >
> > Index: gcc/tree-ssa-address.c
> > ===================================================================
> > --- gcc/tree-ssa-address.c (revision 211771)
> > +++ gcc/tree-ssa-address.c (working copy)
> > @@ -393,7 +393,7 @@ create_mem_ref_raw (tree type, tree alia
> > ??? As IVOPTs does not follow restrictions to where the base
> > pointer may point to create a MEM_REF only if we know that
> > base is valid. */
> > - if ((TREE_CODE (base) == ADDR_EXPR || TREE_CODE (base) == INTEGER_CST)
> > + if (is_gimple_mem_ref_addr (base)
> > && (!index2 || integer_zerop (index2))
> > && (!addr->index || integer_zerop (addr->index)))
> > return fold_build2 (MEM_REF, type, base, addr->offset);
prev parent reply other threads:[~2014-06-18 10:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-18 9:58 Richard Biener
2014-06-18 10:04 ` Jakub Jelinek
2014-06-18 10:31 ` Richard Biener [this message]
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