Xi Ruoyao <[email protected]> writes:
> The logic of par_const_vector_shf_set_operand (actually,
> loongarch_const_vector_shuffle_set_p) expect mode to have the same
> element count as the shuffled vector. But the lsx_vshuf4i_<lsxfmt_f>
> definition have VOIDmode for the mode of the selector, thus the
> predicate actually accepts anything. The issue was somehow latent until
> recently fwprop1 seems improved on folding two vec_select into one.
>
> Change par_const_vector_shf_set_operand to a special predicate so we can
> specify a mode different from the actual mode of the selector parallel
> (in VOIDmode) to the predicate. Then specify VIMODE to satisfy the
> expectation of loongarch_const_vector_shuffle_set_p.
>
> gcc/
>
> * config/loongarch/predicates.md
> (par_const_vector_shf_set_operand): Define as special predicate.
> * config/loongarch/lsx.md (lsx_vshuf4i_<lsxfmt_f>): Pass VIMODE
> to the predicate of selector.
>
> gcc/testsuite/
>
> * gcc.target/loongarch/vector/lsx/pr126200.c: New test.
> ---
>
> Bootstrapped and regtested on loongarch64-linux-gnu. Ok for trunk?
LGTM, thanks.
> gcc/config/loongarch/lsx.md | 2 +-
> gcc/config/loongarch/predicates.md | 2 +-
> .../gcc.target/loongarch/vector/lsx/pr126200.c | 11 +++++++++++
> 3 files changed, 13 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/loongarch/vector/lsx/pr126200.c
>
> diff --git a/gcc/config/loongarch/lsx.md b/gcc/config/loongarch/lsx.md
> index 66359949a42..0d561cc665e 100644
> --- a/gcc/config/loongarch/lsx.md
> +++ b/gcc/config/loongarch/lsx.md
> @@ -1598,7 +1598,7 @@ (define_insn "lsx_vshuf4i_<lsxfmt_f>"
> [(set (match_operand:LSX_WHB_W 0 "register_operand" "=f")
> (vec_select:LSX_WHB_W
> (match_operand:LSX_WHB_W 1 "register_operand" "f")
> - (match_operand 2 "par_const_vector_shf_set_operand" "")))]
> + (match_operand:<VIMODE> 2 "par_const_vector_shf_set_operand" "")))]
> "ISA_HAS_LSX"
> {
> HOST_WIDE_INT val = 0;
> diff --git a/gcc/config/loongarch/predicates.md
> b/gcc/config/loongarch/predicates.md
> index 9e686846514..ced79fe6f50 100644
> --- a/gcc/config/loongarch/predicates.md
> +++ b/gcc/config/loongarch/predicates.md
> @@ -684,7 +684,7 @@ (define_predicate "const_vector_neg_fp_operand"
> op));
> })
>
> -(define_predicate "par_const_vector_shf_set_operand"
> +(define_special_predicate "par_const_vector_shf_set_operand"
> (match_code "parallel")
> {
> return loongarch_const_vector_shuffle_set_p (op, mode);
> diff --git a/gcc/testsuite/gcc.target/loongarch/vector/lsx/pr126200.c
> b/gcc/testsuite/gcc.target/loongarch/vector/lsx/pr126200.c
> new file mode 100644
> index 00000000000..a76748ae0cb
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/loongarch/vector/lsx/pr126200.c
> @@ -0,0 +1,11 @@
> +/* { dg-do assemble } */
> +/* { dg-options "-O2 -mlsx" } */
> +
> +typedef signed char v16i8 __attribute__ ((vector_size (16), aligned (16)));
> +
> +v16i8
> +lsx_convert_utf16_to_utf8 (v16i8 in)
> +{
> + v16i8 x = __builtin_lsx_vshuf4i_b (in, 0b10110001);
> + return __builtin_lsx_vpickev_b (x, x);
> +}
