On Tue, May 21, 2024 at 3:14 PM Haochen Jiang <haochen.ji...@intel.com> wrote:
>
> Hi all,
>
> This is the v2 patch to fix PR115069. The new testcase has passed.
>
> Changes in v2:
> - Added a testcase.
> - Change the comment for the early exit.
>
> Thx,
> Haochen
>
> Since vpermq is really slow, we should avoid using it for permutation
> when vpmovwb is not available (needs AVX512BW) for ix86_expand_vecop_qihi2
> and fall back to ix86_expand_vecop_qihi.
>
> gcc/ChangeLog:
>
> PR target/115069
> * config/i386/i386-expand.cc (ix86_expand_vecop_qihi2):
> Do not enable the optimization when AVX512BW is not enabled.
>
> gcc/testsuite/ChangeLog:
>
> PR target/115069
> * gcc.target/i386/pr115069.c: New.
> ---
> gcc/config/i386/i386-expand.cc | 7 +++
> gcc/testsuite/gcc.target/i386/pr115069.c | 78 ++++++++++++++++++++++++
> 2 files changed, 85 insertions(+)
> create mode 100644 gcc/testsuite/gcc.target/i386/pr115069.c
>
> diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
> index a6132911e6a..f7939761879 100644
> --- a/gcc/config/i386/i386-expand.cc
> +++ b/gcc/config/i386/i386-expand.cc
> @@ -24323,6 +24323,13 @@ ix86_expand_vecop_qihi2 (enum rtx_code code, rtx
> dest, rtx op1, rtx op2)
> bool op2vec = GET_MODE_CLASS (GET_MODE (op2)) == MODE_VECTOR_INT;
> bool uns_p = code != ASHIFTRT;
>
> + /* Without VPMOVWB (provided by AVX512BW ISA), the expansion uses the
> + generic permutation to merge the data back into the right place. This
> + permutation results in VPERMQ, which is slow, so better fall back to
> + ix86_expand_vecop_qihi. */
> + if (!TARGET_AVX512BW)
> + return false;
> +
> if ((qimode == V16QImode && !TARGET_AVX2)
> || (qimode == V32QImode && (!TARGET_AVX512BW || !TARGET_EVEX512))
> /* There are no V64HImode instructions. */
> diff --git a/gcc/testsuite/gcc.target/i386/pr115069.c
> b/gcc/testsuite/gcc.target/i386/pr115069.c
> new file mode 100644
> index 00000000000..c4b48b602ef
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr115069.c
> @@ -0,0 +1,78 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mavx2" } */
> +/* { dg-final { scan-assembler-not "vpermq" } } */
> +
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <stdlib.h>
> +#include <inttypes.h>
> +
> +typedef int8_t stress_vint8_t __attribute__ ((vector_size (16)));
No need for such big testcase,
typedef char v16qi __attribute__((vector_size(16)));
v16qi
foo (v16qi a, v16qi b)
{
return a * b;
}
should be enough, with -mavx2 -mno-avx512f
> +
> +#define OPS(a, b, c, s, v23, v3) \
> +do { \
> + a += b; \
> + a |= b; \
> + a -= b; \
> + a &= ~b; \
> + a *= c; \
> + a = ~a; \
> + a *= s; \
> + a ^= c; \
> + a <<= 1; \
> + b >>= 1; \
> + b += c; \
> + a %= v23; \
> + c /= v3; \
> + b = b ^ c; \
> + c = b ^ c; \
> + b = b ^ c; \
> +} while (0)
> +
> +volatile uint8_t csum8_put;
> +
> +void stress_vecmath(void)
> +{
> + const stress_vint8_t v23_8 = {
> + 0x17, 0x17, 0x17, 0x17, 0x17, 0x17, 0x17, 0x17,
> + 0x17, 0x17, 0x17, 0x17, 0x17, 0x17, 0x17, 0x17
> + };
> + const stress_vint8_t v3_8 = {
> + 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
> + 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03
> + };
> + stress_vint8_t a8 = {
> + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
> + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
> + };
> + stress_vint8_t b8 = {
> + 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
> + 0x0f, 0x1e, 0x2d, 0x3c, 0x4b, 0x5a, 0x69, 0x78
> + };
> + stress_vint8_t c8 = {
> + 0x01, 0x02, 0x03, 0x02, 0x01, 0x02, 0x03, 0x02,
> + 0x03, 0x02, 0x01, 0x02, 0x03, 0x02, 0x01, 0x02
> + };
> + stress_vint8_t s8 = {
> + 0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, 0x02,
> + 0x01, 0x01, 0x02, 0x02, 0x01, 0x01, 0x02, 0x02,
> + };
> + const uint8_t csum8_val = (uint8_t)0x1b;
> + int i;
> + uint8_t csum8;
> +
> + for (i = 1000; i; i--) {
> + OPS(a8, b8, c8, s8, v23_8, v3_8);
> + OPS(a8, b8, c8, s8, v23_8, v3_8);
> + OPS(a8, b8, c8, s8, v23_8, v3_8);
> + OPS(a8, b8, c8, s8, v23_8, v3_8);
> + OPS(a8, b8, c8, s8, v23_8, v3_8);
> + OPS(a8, b8, c8, s8, v23_8, v3_8);
> + }
> +
> + csum8 = a8[0] ^ a8[1] ^ a8[2] ^ a8[3] ^
> + a8[4] ^ a8[5] ^ a8[6] ^ a8[7] ^
> + a8[8] ^ a8[9] ^ a8[10] ^ a8[11] ^
> + a8[12] ^ a8[13] ^ a8[14] ^ a8[15];
> + csum8_put = csum8;
> +}
> --
> 2.31.1
>
--
BR,
Hongtao
