On Tue, Mar 16, 2021 at 10:23 PM HAO CHEN GUI <guih...@linux.ibm.com> wrote:
>
> Segher,
>
> The const_anchor should work on both 64 and 32 bit. I think the
> constant loading is cheap on 32 bit platform, so I only enabled it on
> 64 bit. I will add a test case and verify the patch on Darwin and AIX.
I will say this more strongly: No, this patch is not approved.
Thanks, David
> Thanks.
>
> On 17/3/2021 上午 12:35, Segher Boessenkool wrote:
> > Hi!
> >
> > On Mon, Mar 15, 2021 at 11:11:32AM +0800, HAO CHEN GUI via Gcc-patches
> > wrote:
> >> This patch adds const_anchor for rs6000. The const_anchor is used
> >> in cse pass.
> > 1) This isn't suitable for stage 4.
> > 2) Please add a test case, which shows what it does, that it is useful.
> > 3) Does this work on other OSes than Linux? What about Darwin and AIX?
> >
> >> 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;
> >> + }
> > Why only on 64 bit? Why these choices?
> >
> >
> > Segher
