On Fri, Aug 5, 2022 at 6:16 AM Tamar Christina via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Hi All,
>
> This excludes value_replacement and store_elim from diamonds as they don't
> handle the form properly.
>
> Bootstrapped Regtested on aarch64-none-linux-gnu, x86_64-pc-linux-gnu
> and no issues.
>
> Ok for master?
I just noticed this changes the behavior of the store elimination pass
to also act like phi-opt if bb layout was a diamond.
I will be submitting a patch for GCC 14 to revert back that behavior
with some refactoring I am doing to improve the readability of the
code.
Thanks,
Andrew Pinski
>
> Thanks,
> Tamar
>
> gcc/ChangeLog:
>
> PR middle-end/106534
> * tree-ssa-phiopt.cc (tree_ssa_phiopt_worker): Guard the
> value_replacement and store_elim from diamonds.
>
> --- inline copy of patch --
> diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
> index
> bdbf52916b0f88ee4f475e1fa306046d61f13d53..1e002c608591836ffb001724b3f469a8d042ae5e
> 100644
> --- a/gcc/tree-ssa-phiopt.cc
> +++ b/gcc/tree-ssa-phiopt.cc
> @@ -283,7 +283,7 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool
> do_hoist_loads, bool early_p)
> || (e1->flags & EDGE_FALLTHRU) == 0)
> continue;
>
> - if (do_store_elim)
> + if (do_store_elim && !diamond_p)
> {
> /* Also make sure that bb1 only have one predecessor and that it
> is bb. */
> @@ -310,7 +310,7 @@ tree_ssa_phiopt_worker (bool do_store_elim, bool
> do_hoist_loads, bool early_p)
>
> /* Value replacement can work with more than one PHI
> so try that first. */
> - if (!early_p)
> + if (!early_p && !diamond_p)
> for (gsi = gsi_start (phis); !gsi_end_p (gsi); gsi_next (&gsi))
> {
> phi = as_a <gphi *> (gsi_stmt (gsi));
>
>
>
>
> --
