On Tue, 20 Sep 2016, Doug Gilmore wrote:
> It looks like the original message was dropped, resending.
>
> Doug
> ________________________________________
> From: Doug Gilmore
> Sent: Tuesday, September 20, 2016 2:12 PM
> To: gcc-patches@gcc.gnu.org; rgue...@gcc.gnu.org
> Subject: [PATCH] Fix PR tree-optimization/77654
>
> From:
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77654
>
> Richard Biener wrote:
> > Looks good though addr_base should always be a pointer but it might
> > not be an SSA name so better check that...
>
> I took a look at other situations where duplicate_ssa_name_ptr_info()
> is called and found that there are no checks for the SSA name since
> that check is done in duplicate_ssa_name_ptr_info(). Do you still
> want the additional check added?
It checks for !ptr_info but it requires NAME to be an SSA name.
>From the attachment in bugzilla (the attachment didn't make it
here)
+
+ if (POINTER_TYPE_P (TREE_TYPE (addr_base)))
+ {
+ duplicate_ssa_name_ptr_info (addr, SSA_NAME_PTR_INFO
(addr_base));
+ /* As this isn't a plain copy we have to reset alignment
+ information. */
+ if (SSA_NAME_PTR_INFO (addr))
+ mark_ptr_info_alignment_unknown (SSA_NAME_PTR_INFO (addr));
+ }
+
I was talking about changing the if to
if (TREE_CODE (addr_base) == SSA_NAME
&& TREE_CODE (addr) == SSA_NAME)
because the addresses could be invariant as far as I can see.
> Also does it make sense to make a test case for this?
I'm not sure how to easily test this.
Richard.
> I was thinking of making the following change to:
>
> diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
> index 8051a66..b799c43 100644
> --- a/gcc/tree-ssa-alias.c
> +++ b/gcc/tree-ssa-alias.c
> @@ -296,7 +296,16 @@ ptr_derefs_may_alias_p (tree ptr1, tree ptr2)
> pi1 = SSA_NAME_PTR_INFO (ptr1);
> pi2 = SSA_NAME_PTR_INFO (ptr2);
> if (!pi1 || !pi2)
> - return true;
> + {
> + if (dump_file)
> + {
> + if (! pi1)
> + fprintf (dump_file, "%s pi1 is NULL\n", __FUNCTION__);
> + if (! pi2)
> + fprintf (dump_file, "%s pi2 is NULL\n", __FUNCTION__);
> + }
> + return true;
> + }
>
> Then when compiling the test case, we could scan for the RE
> "pi. is NULL" in the dump file created by compiling with -fdump-rtl-sched2.
>
> I attached the original patch.
>
> Thanks,
>
> Doug
>
> gcc/
> PR tree-optimization/77654
> * tree-ssa-alias.c (issue_prefetch_ref): Add call
> to duplicate_ssa_name_ptr_info.
>
>
--
Richard Biener <rguent...@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB
21284 (AG Nuernberg)
