I suspect that this is incorrect. Did you look at the discussion of
the choice of anchor limits when first implemented? We specifically
chose 32 bit range.
Thanks, David
On Tue, Mar 16, 2021 at 10:21 AM will schmidt <will_schm...@vnet.ibm.com> wrote:
>
> On Mon, 2021-03-15 at 11:11 +0800, HAO CHEN GUI via Gcc-patches wrote:
> > Hi,
> >
> > This patch adds const_anchor for rs6000. The const_anchor is used
> > in cse pass.
> >
> > The attachment are the patch diff and change log file.
> >
> > Bootstrapped and tested on powerpc64le with no regressions. Is this
> > okay for trunk? Any recommendations? Thanks a lot.
>
>
> Be sure to CC David and Segher to help ensure they see the arch
> specific patch. :-)
> >
>
> > * config/rs6000/rs6000.c (rs6000_option_override_internal): Set
> > targetm.const_anchor, targetm.min_anchor_offset
> > and targetm.max_anchor_offset.
>
>
> lgtm.
>
>
> > diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
> > index ec068c58aa5..2b2350c53ae 100644
> > --- a/gcc/config/rs6000/rs6000.c
> > +++ b/gcc/config/rs6000/rs6000.c
> > @@ -4911,6 +4911,13 @@ rs6000_option_override_internal (bool global_init_p)
> > warning (0, "%qs is deprecated and not recommended in any
> > circumstances",
> > "-mno-speculate-indirect-jumps");
> >
> > + if (TARGET_64BIT)
> > + {
> > + targetm.min_anchor_offset = -32768;
> > + targetm.max_anchor_offset = 32767;
> > + targetm.const_anchor = 0x8000;
> > + }
> > +
>
>
> The mix of decimal and hexadecimal notation catches my eye, but
> this matches the style I see for other architectures, mips in
> particular.
>
> Do we want/need to explicitly set the values for !TARGET_64BIT ? (I
> can't immediately tell what the default values are).
>
> lgtm.
>
>
> > return ret;
> > }
> >
>
