[i386] Add combine splitter to transform vashr/vlshr/vashl_optab to ashr/lshr/ashl_optab for const vector duplicate operand.

  Hi,

This patch add combine splitter to transform vashr/vlshr/vashl_optab to ashr/lshr/ashl_optab for const vector duplicate operand.

Regtested on x86_64-pc-linux-gnu. Ok for trunk?

BRs,
Haochen

gcc/ChangeLog:

	PR target/101796
	* config/i386/predicates.md (const_vector_operand):
	Add new predicate.
	* config/i386/sse.md(<insn><mode>3<mask_name>):
	Add new define_split below.

gcc/testsuite/ChangeLog:

	PR target/101796
	* gcc.target/i386/pr101796-1.c: New test.
---
 gcc/config/i386/predicates.md              | 13 +++++++++++++
 gcc/config/i386/sse.md                     | 14 ++++++++++++++
 gcc/testsuite/gcc.target/i386/pr101796-1.c | 20 ++++++++++++++++++++
 3 files changed, 47 insertions(+)
 create mode 100755 gcc/testsuite/gcc.target/i386/pr101796-1.c
  

On Wed, Dec 8, 2021 at 2:47 PM Haochen Jiang via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Hi,
>
> This patch add combine splitter to transform vashr/vlshr/vashl_optab to ashr/lshr/ashl_optab for const vector duplicate operand.
>
> Regtested on x86_64-pc-linux-gnu. Ok for trunk?
Ok.
>
> BRs,
> Haochen
>
> gcc/ChangeLog:
>
>         PR target/101796
>         * config/i386/predicates.md (const_vector_operand):
>         Add new predicate.
>         * config/i386/sse.md(<insn><mode>3<mask_name>):
>         Add new define_split below.
>
> gcc/testsuite/ChangeLog:
>
>         PR target/101796
>         * gcc.target/i386/pr101796-1.c: New test.
> ---
>  gcc/config/i386/predicates.md              | 13 +++++++++++++
>  gcc/config/i386/sse.md                     | 14 ++++++++++++++
>  gcc/testsuite/gcc.target/i386/pr101796-1.c | 20 ++++++++++++++++++++
>  3 files changed, 47 insertions(+)
>  create mode 100755 gcc/testsuite/gcc.target/i386/pr101796-1.c
>
> diff --git a/gcc/config/i386/predicates.md b/gcc/config/i386/predicates.md
> index 4ccbe11b842..770e2f0c0dd 100644
> --- a/gcc/config/i386/predicates.md
> +++ b/gcc/config/i386/predicates.md
> @@ -1844,6 +1844,19 @@
>    return true;
>  })
>
> +;; Return true if OP is a const vector with duplicate value.
> +(define_predicate "const_vector_duplicate_operand"
> +  (match_code "const_vector")
> +{
> +  rtx elt = XVECEXP (op, 0, 0);
> +  int i, nelt = XVECLEN (op, 0);
> +
> +  for (i = 1; i < nelt; ++i)
> +    if (!rtx_equal_p (elt, XVECEXP (op, 0, i)))
> +      return false;
> +  return true;
> +})
> +
>  ;; Return true if OP is a parallel for a vbroadcast permute.
>  (define_predicate "avx_vbroadcast_operand"
>    (and (match_code "parallel")
> diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
> index 08bdcddc111..a2c0c1209c7 100644
> --- a/gcc/config/i386/sse.md
> +++ b/gcc/config/i386/sse.md
> @@ -15232,6 +15232,20 @@
>         (const_string "0")))
>     (set_attr "mode" "<sseinsnmode>")])
>
> +;; PR target/101796: Transfrom movl+vpbranchcastw+vpsravw to vpsraw
> +;; when COUNT is immediate.
> +(define_split
> +  [(set (match_operand:VI248_AVX512BW 0 "register_operand")
> +       (any_shift:VI248_AVX512BW
> +         (match_operand:VI248_AVX512BW 1 "nonimmediate_operand")
> +         (match_operand:VI248_AVX512BW 2 "const_vector_duplicate_operand")))]
> +  "TARGET_AVX512F && GET_MODE_UNIT_BITSIZE (<MODE>mode)
> +   > INTVAL (XVECEXP (operands[2], 0, 0))"
> +  [(set (match_dup 0)
> +       (any_shift:VI248_AVX512BW
> +         (match_dup 1)
> +         (match_dup 3)))]
> +  "operands[3] = XVECEXP (operands[2], 0, 0);")
>
>  (define_expand "vec_shl_<mode>"
>    [(set (match_dup 3)
> diff --git a/gcc/testsuite/gcc.target/i386/pr101796-1.c b/gcc/testsuite/gcc.target/i386/pr101796-1.c
> new file mode 100755
> index 00000000000..32ae5909913
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr101796-1.c
> @@ -0,0 +1,20 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mavx512bw" } */
> +/* { dg-final {scan-assembler-times "vpsrlw\[ \\t\]" 1 } } */
> +/* { dg-final {scan-assembler-times "vpsllw\[ \\t\]" 1 } } */
> +/* { dg-final {scan-assembler-times "vpsraw\[ \\t\]" 1 } } */
> +/* { dg-final {scan-assembler-not "vpbroadcastw\[ \\t\]" } } */
> +/* { dg-final {scan-assembler-not "vpsrlvw\[ \\t\]" } } */
> +/* { dg-final {scan-assembler-not "vpsllvw\[ \\t\]" } } */
> +/* { dg-final {scan-assembler-not "vpsravw\[ \\t\]" } } */
> +#include <immintrin.h>
> +
> +volatile __m512i a, b;
> +
> +void
> +foo()
> +{
> +  b = _mm512_srlv_epi16 (a, _mm512_set1_epi16 (3));
> +  b = _mm512_sllv_epi16 (a, _mm512_set1_epi16 (4));
> +  b = _mm512_srav_epi16 (a, _mm512_set1_epi16 (5));
> +}
> --
> 2.18.1
>