On Tue, Sep 24, 2024 at 6:14 PM Andrew Pinski <quic_apin...@quicinc.com> wrote:
>
> Another small phiprop improvement, in some cases
> we could have a vop defining statement be a phi which might
> be the same bb as the load happens. This is ok since the phi
> here is not a store so we can just accept it.
>
> Bootstrapped and tested on x86_64-linux-gnu.
OK.
> PR tree-optimization/116824
>
> gcc/ChangeLog:
>
> * tree-ssa-phiprop.cc (propagate_with_phi): Don't
> reject if the bb of the def_stmt is the same as load
> and if the def_stmt was a phi.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/phiprop-3.c: New test.
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/testsuite/gcc.dg/tree-ssa/phiprop-3.c | 30 +++++++++++++++++++++++
> gcc/tree-ssa-phiprop.cc | 3 ++-
> 2 files changed, 32 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/phiprop-3.c
>
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phiprop-3.c
> b/gcc/testsuite/gcc.dg/tree-ssa/phiprop-3.c
> new file mode 100644
> index 00000000000..a0d5891dc60
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/phiprop-3.c
> @@ -0,0 +1,30 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fdump-tree-phiprop1-details -fdump-tree-cselim-details
> -fdump-tree-phiopt2" } */
> +
> +/* PR tree-optimization/116824 */
> +/* phiprop should be able to handle the case where the vops defining
> + statement was a phi in the same bb as the deference. */
> +
> +int g(int i, int *tt)
> +{
> + const int t = 10;
> + const int *a;
> + {
> + if (t < i)
> + {
> + *tt = 1;
> + a = &t;
> + }
> + else
> + {
> + *tt = 1;
> + a = &i;
> + }
> + }
> + return *a;
> +}
> +
> +/* { dg-final { scan-tree-dump-times "Inserting PHI for result of load" 1
> "phiprop1"} } */
> +/* { dg-final { scan-tree-dump-times "factoring out stores" 1 "cselim"} } */
> +/* { dg-final { scan-tree-dump-times "MIN_EXPR" 1 "phiopt2"} } */
> +
> diff --git a/gcc/tree-ssa-phiprop.cc b/gcc/tree-ssa-phiprop.cc
> index f04990e8cb4..4d1df7d351e 100644
> --- a/gcc/tree-ssa-phiprop.cc
> +++ b/gcc/tree-ssa-phiprop.cc
> @@ -401,7 +401,8 @@ propagate_with_phi (basic_block bb, gphi *phi, struct
> phiprop_d *phivn,
> def_stmt = SSA_NAME_DEF_STMT (vuse);
> }
> if (!SSA_NAME_IS_DEFAULT_DEF (vuse)
> - && (gimple_bb (def_stmt) == bb
> + && ((gimple_bb (def_stmt) == bb
> + && !is_a<gphi *>(def_stmt))
> || (gimple_bb (def_stmt)
> && !dominated_by_p (CDI_DOMINATORS,
> bb, gimple_bb (def_stmt)))))
> --
> 2.43.0
>
