On Thu, Mar 7, 2024 at 1:25 PM Robin Dapp <rdapp....@gmail.com> wrote:
>
> Attached v2 combines the checks.
>
> Bootstrapped and regtested on x86 an power10, aarch64 still running.
> Regtested on riscv64.
LGTM.
> Regards
> Robin
>
>
> Subject: [PATCH v2] vect: Do not peel epilogue for partial vectors.
>
> r14-7036-gcbf569486b2dec added an epilogue vectorization guard for early
> break but PR114196 shows that we also run into the problem without early
> break. Therefore merge the condition into the topmost vectorization
> guard.
>
> gcc/ChangeLog:
>
> PR middle-end/114196
>
> * tree-vect-loop-manip.cc (vect_can_peel_nonlinear_iv_p): Merge
> vectorization guards.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.target/aarch64/pr114196.c: New test.
> * gcc.target/riscv/rvv/autovec/pr114196.c: New test.
> ---
> gcc/testsuite/gcc.target/aarch64/pr114196.c | 19 ++++++++++++
> .../gcc.target/riscv/rvv/autovec/pr114196.c | 19 ++++++++++++
> gcc/tree-vect-loop-manip.cc | 30 +++++--------------
> 3 files changed, 45 insertions(+), 23 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/aarch64/pr114196.c
> create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/pr114196.c
>
> diff --git a/gcc/testsuite/gcc.target/aarch64/pr114196.c
> b/gcc/testsuite/gcc.target/aarch64/pr114196.c
> new file mode 100644
> index 00000000000..15e4b0e31b8
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/pr114196.c
> @@ -0,0 +1,19 @@
> +/* { dg-do compile } */
> +/* { dg-options { -O3 -fno-vect-cost-model -march=armv9-a
> -msve-vector-bits=256 } } */
> +
> +unsigned a;
> +int b;
> +long *c;
> +
> +int
> +main ()
> +{
> + for (int d = 0; d < 22; d += 4) {
> + b = ({
> + int e = c[d];
> + e;
> + })
> + ? 0 : -c[d];
> + a *= 3;
> + }
> +}
> diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr114196.c
> b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr114196.c
> new file mode 100644
> index 00000000000..7ba9cbbed70
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr114196.c
> @@ -0,0 +1,19 @@
> +/* { dg-do compile } */
> +/* { dg-options { -O3 -fno-vect-cost-model -march=rv64gcv_zvl256b
> -mabi=lp64d -mrvv-vector-bits=zvl } } */
> +
> +unsigned a;
> +int b;
> +long *c;
> +
> +int
> +main ()
> +{
> + for (int d = 0; d < 22; d += 4) {
> + b = ({
> + int e = c[d];
> + e;
> + })
> + ? 0 : -c[d];
> + a *= 3;
> + }
> +}
> diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
> index f72da915103..56a6d8e4a8d 100644
> --- a/gcc/tree-vect-loop-manip.cc
> +++ b/gcc/tree-vect-loop-manip.cc
> @@ -2129,16 +2129,19 @@ vect_can_peel_nonlinear_iv_p (loop_vec_info
> loop_vinfo,
> For mult, don't known how to generate
> init_expr * pow (step, niters) for variable niters.
> For neg, it should be ok, since niters of vectorized main loop
> - will always be multiple of 2. */
> - if ((!LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo)
> - || !LOOP_VINFO_VECT_FACTOR (loop_vinfo).is_constant ())
> + will always be multiple of 2.
> + See also PR113163 and PR114196. */
> + if ((!LOOP_VINFO_VECT_FACTOR (loop_vinfo).is_constant ()
> + || LOOP_VINFO_USING_PARTIAL_VECTORS_P (loop_vinfo)
> + || !LOOP_VINFO_NITERS_KNOWN_P (loop_vinfo))
> && induction_type != vect_step_op_neg)
> {
> if (dump_enabled_p ())
> dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
> "Peeling for epilogue is not supported"
> " for nonlinear induction except neg"
> - " when iteration count is unknown.\n");
> + " when iteration count is unknown or"
> + " when using partial vectorization.\n");
> return false;
> }
>
> @@ -2178,25 +2181,6 @@ vect_can_peel_nonlinear_iv_p (loop_vec_info loop_vinfo,
> return false;
> }
>
> - /* We can't support partial vectors and early breaks with an induction
> - type other than add or neg since we require the epilog and can't
> - perform the peeling. The below condition mirrors that of
> - vect_gen_vector_loop_niters where niters_vector_mult_vf_var then sets
> - step_vector to VF rather than 1. This is what creates the nonlinear
> - IV. PR113163. */
> - if (LOOP_VINFO_EARLY_BREAKS (loop_vinfo)
> - && LOOP_VINFO_VECT_FACTOR (loop_vinfo).is_constant ()
> - && LOOP_VINFO_USING_PARTIAL_VECTORS_P (loop_vinfo)
> - && induction_type != vect_step_op_neg)
> - {
> - if (dump_enabled_p ())
> - dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
> - "Peeling for epilogue is not supported"
> - " for nonlinear induction except neg"
> - " when VF is known and early breaks.\n");
> - return false;
> - }
> -
> return true;
> }
>
> --
> 2.43.2
>
