On Fri, 18 Oct 2024, Richard Sandiford wrote:
> This patch extends get_nonzero_bits to handle POLY_INT_CSTs,
> The easiest (but also most useful) case is that the number
> of trailing zeros in the runtime value is at least the number
> of trailing zeros in each individual component.
>
> In principle, we could do this for coeffs 1 and above only,
> and then OR in ceoff 0. This would give ~0x11 for [14, 32], say.
> But that's future work.
>
> gcc/
> * tree-ssanames.cc (get_nonzero_bits): Handle POLY_INT_CSTs.
> * match.pd (with_possible_nonzero_bits): Likewise.
>
> gcc/testsuite/
> * gcc.target/aarch64/sve/cnt_fold_4.c: New test.
> ---
> gcc/match.pd | 2 +
> .../gcc.target/aarch64/sve/cnt_fold_4.c | 61 +++++++++++++++++++
> gcc/tree-ssanames.cc | 3 +
> 3 files changed, 66 insertions(+)
> create mode 100644 gcc/testsuite/gcc.target/aarch64/sve/cnt_fold_4.c
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 540582dc984..41903554478 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -2893,6 +2893,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> possibly set. */
> (match with_possible_nonzero_bits
> INTEGER_CST@0)
> +(match with_possible_nonzero_bits
> + POLY_INT_CST@0)
> (match with_possible_nonzero_bits
> SSA_NAME@0
> (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)) || POINTER_TYPE_P (TREE_TYPE (@0)))))
> diff --git a/gcc/testsuite/gcc.target/aarch64/sve/cnt_fold_4.c
> b/gcc/testsuite/gcc.target/aarch64/sve/cnt_fold_4.c
> new file mode 100644
> index 00000000000..b7a53701993
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/sve/cnt_fold_4.c
> @@ -0,0 +1,61 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2" } */
> +/* { dg-final { check-function-bodies "**" "" } } */
> +
> +#include <arm_sve.h>
> +
> +/*
> +** f1:
> +** cnth x0
> +** ret
> +*/
> +uint64_t
> +f1 ()
> +{
> + uint64_t x = svcntw ();
> + x >>= 2;
> + return x << 3;
> +}
> +
> +/*
> +** f2:
> +** [^\n]+
> +** [^\n]+
> +** ...
> +** ret
> +*/
> +uint64_t
> +f2 ()
> +{
> + uint64_t x = svcntd ();
> + x >>= 2;
> + return x << 3;
> +}
> +
> +/*
> +** f3:
> +** cntb x0, all, mul #4
> +** ret
> +*/
> +uint64_t
> +f3 ()
> +{
> + uint64_t x = svcntd ();
> + x >>= 1;
> + return x << 6;
> +}
> +
> +/*
> +** f4:
> +** [^\n]+
> +** [^\n]+
> +** ...
> +** ret
> +*/
> +uint64_t
> +f4 ()
> +{
> + uint64_t x = svcntd ();
> + x >>= 2;
> + return x << 2;
> +}
> diff --git a/gcc/tree-ssanames.cc b/gcc/tree-ssanames.cc
> index 4f83fcbb517..d2d1ec18797 100644
> --- a/gcc/tree-ssanames.cc
> +++ b/gcc/tree-ssanames.cc
> @@ -505,6 +505,9 @@ get_nonzero_bits (const_tree name)
> /* Use element_precision instead of TYPE_PRECISION so complex and
> vector types get a non-zero precision. */
> unsigned int precision = element_precision (TREE_TYPE (name));
> + if (POLY_INT_CST_P (name))
> + return -known_alignment (wi::to_poly_wide (name));
> +
Since you don't need precision can you move this right after the
INTEGER_CST handling?
OK with that change.
Thanks,
Richard.
> if (POINTER_TYPE_P (TREE_TYPE (name)))
> {
> struct ptr_info_def *pi = SSA_NAME_PTR_INFO (name);
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
