On Wed, Aug 21, 2024 at 7:40 AM liuhongt <[email protected]> wrote:
>
> When none of mprefer-vector-width, avx256_optimal/avx128_optimal,
> avx256_store_by_pieces/avx512_store_by_pieces is specified, GCC will
> set ix86_{move_max,store_max} as max available vector length except
> for AVX part.
>
> if (TARGET_AVX512F_P (opts->x_ix86_isa_flags)
> && TARGET_EVEX512_P (opts->x_ix86_isa_flags2))
> opts->x_ix86_move_max = PVW_AVX512;
> else
> opts->x_ix86_move_max = PVW_AVX128;
>
> So for -mavx2, vectorizer will choose 256-bit for vectorization, but
> 128-bit is used for struct copy, there could be a potential STLF issue
> due to this "misalign".
>
> The patch fixes that and improved 538.imagick_r by ~30% for -march=x86-64-v3
> -O2.
> Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
> Any comments?
Should we look at the avx128_optimal tune and/or avx256_split_regs and
avx256_optimal
also for 512? Because IIRC the vectorizers default looks at that as
well (OTOH larger
stores should be fine for STLF).
> gcc/ChangeLog:
>
> * config/i386/i386-options.cc (ix86_option_override_internal):
> set ix86_{move_max,store_max} to PVW_AVX256 when TARGET_AVX
> instead of PVW_AVX128.
>
> gcc/testsuite/ChangeLog:
> * gcc.target/i386/pieces-memcpy-10.c: Add -mprefer-vector-width=128.
> * gcc.target/i386/pieces-memcpy-6.c: Ditto.
> * gcc.target/i386/pieces-memset-38.c: Ditto.
> * gcc.target/i386/pieces-memset-40.c: Ditto.
> * gcc.target/i386/pieces-memset-41.c: Ditto.
> * gcc.target/i386/pieces-memset-42.c: Ditto.
> * gcc.target/i386/pieces-memset-43.c: Ditto.
> * gcc.target/i386/pieces-strcpy-2.c: Ditto.
> * gcc.target/i386/pieces-memcpy-22.c: New test.
> * gcc.target/i386/pieces-memset-51.c: New test.
> * gcc.target/i386/pieces-strcpy-3.c: New test.
> ---
> gcc/config/i386/i386-options.cc | 6 ++++++
> gcc/testsuite/gcc.target/i386/pieces-memcpy-10.c | 2 +-
> gcc/testsuite/gcc.target/i386/pieces-memcpy-22.c | 12 ++++++++++++
> gcc/testsuite/gcc.target/i386/pieces-memcpy-6.c | 2 +-
> gcc/testsuite/gcc.target/i386/pieces-memset-38.c | 2 +-
> gcc/testsuite/gcc.target/i386/pieces-memset-40.c | 2 +-
> gcc/testsuite/gcc.target/i386/pieces-memset-41.c | 2 +-
> gcc/testsuite/gcc.target/i386/pieces-memset-42.c | 2 +-
> gcc/testsuite/gcc.target/i386/pieces-memset-43.c | 2 +-
> gcc/testsuite/gcc.target/i386/pieces-memset-51.c | 12 ++++++++++++
> gcc/testsuite/gcc.target/i386/pieces-strcpy-2.c | 2 +-
> gcc/testsuite/gcc.target/i386/pieces-strcpy-3.c | 15 +++++++++++++++
> 12 files changed, 53 insertions(+), 8 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/pieces-memcpy-22.c
> create mode 100644 gcc/testsuite/gcc.target/i386/pieces-memset-51.c
> create mode 100644 gcc/testsuite/gcc.target/i386/pieces-strcpy-3.c
>
> diff --git a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc
> index f423455b363..f79257cc764 100644
> --- a/gcc/config/i386/i386-options.cc
> +++ b/gcc/config/i386/i386-options.cc
> @@ -3023,6 +3023,9 @@ ix86_option_override_internal (bool main_args_p,
> if (TARGET_AVX512F_P (opts->x_ix86_isa_flags)
> && TARGET_EVEX512_P (opts->x_ix86_isa_flags2))
> opts->x_ix86_move_max = PVW_AVX512;
> + /* Align with vectorizer to avoid potential STLF issue. */
> + else if (TARGET_AVX_P (opts->x_ix86_isa_flags))
> + opts->x_ix86_move_max = PVW_AVX256;
> else
> opts->x_ix86_move_max = PVW_AVX128;
> }
> @@ -3047,6 +3050,9 @@ ix86_option_override_internal (bool main_args_p,
> if (TARGET_AVX512F_P (opts->x_ix86_isa_flags)
> && TARGET_EVEX512_P (opts->x_ix86_isa_flags2))
> opts->x_ix86_store_max = PVW_AVX512;
> + /* Align with vectorizer to avoid potential STLF issue. */
> + else if (TARGET_AVX_P (opts->x_ix86_isa_flags))
> + opts->x_ix86_store_max = PVW_AVX256;
> else
> opts->x_ix86_store_max = PVW_AVX128;
> }
> diff --git a/gcc/testsuite/gcc.target/i386/pieces-memcpy-10.c
> b/gcc/testsuite/gcc.target/i386/pieces-memcpy-10.c
> index 5faee21f9b9..53ad0b3be44 100644
> --- a/gcc/testsuite/gcc.target/i386/pieces-memcpy-10.c
> +++ b/gcc/testsuite/gcc.target/i386/pieces-memcpy-10.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile } */
> -/* { dg-options "-O2 -mno-avx2 -mavx -mtune=sandybridge" } */
> +/* { dg-options "-O2 -mno-avx2 -mavx -mprefer-vector-width=128
> -mtune=sandybridge" } */
>
> extern char *dst, *src;
>
> diff --git a/gcc/testsuite/gcc.target/i386/pieces-memcpy-22.c
> b/gcc/testsuite/gcc.target/i386/pieces-memcpy-22.c
> new file mode 100644
> index 00000000000..605b3623ffc
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pieces-memcpy-22.c
> @@ -0,0 +1,12 @@
> +/* { dg-do compile { target { ! ia32 } } } */
> +/* { dg-options "-O2 -mno-avx2 -mavx -mtune=generic" } */
> +
> +extern char *dst, *src;
> +
> +void
> +foo (void)
> +{
> + __builtin_memcpy (dst, src, 33);
> +}
> +
> +/* { dg-final { scan-assembler-times "vmovdqu\[ \\t\]+\[^\n\]*%ymm" 2 } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pieces-memcpy-6.c
> b/gcc/testsuite/gcc.target/i386/pieces-memcpy-6.c
> index 5f99cc98c47..cfd2a86cf33 100644
> --- a/gcc/testsuite/gcc.target/i386/pieces-memcpy-6.c
> +++ b/gcc/testsuite/gcc.target/i386/pieces-memcpy-6.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile { target { ! ia32 } } } */
> -/* { dg-options "-O2 -mno-avx2 -mavx -mtune=sandybridge" } */
> +/* { dg-options "-O2 -mno-avx2 -mavx -mprefer-vector-width=128
> -mtune=sandybridge" } */
>
> extern char *dst, *src;
>
> diff --git a/gcc/testsuite/gcc.target/i386/pieces-memset-38.c
> b/gcc/testsuite/gcc.target/i386/pieces-memset-38.c
> index ed4a24a54fd..ddd194debd5 100644
> --- a/gcc/testsuite/gcc.target/i386/pieces-memset-38.c
> +++ b/gcc/testsuite/gcc.target/i386/pieces-memset-38.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile } */
> -/* { dg-options "-O2 -mno-avx512f -mavx2 -mtune=sandybridge" } */
> +/* { dg-options "-O2 -mno-avx512f -mavx2 -mprefer-vector-width=128
> -mtune=sandybridge" } */
>
> extern char *dst;
>
> diff --git a/gcc/testsuite/gcc.target/i386/pieces-memset-40.c
> b/gcc/testsuite/gcc.target/i386/pieces-memset-40.c
> index 86358c99a83..5878876550c 100644
> --- a/gcc/testsuite/gcc.target/i386/pieces-memset-40.c
> +++ b/gcc/testsuite/gcc.target/i386/pieces-memset-40.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile } */
> -/* { dg-options "-O2 -mno-avx512f -mavx2 -mtune=sandybridge" } */
> +/* { dg-options "-O2 -mno-avx512f -mavx2 -mprefer-vector-width=128
> -mtune=sandybridge" } */
> /* Cope with --enable-frame-pointer, Solaris/x86 -mstackrealign default. */
> /* { dg-additional-options "-fomit-frame-pointer -mno-stackrealign" } */
>
> diff --git a/gcc/testsuite/gcc.target/i386/pieces-memset-41.c
> b/gcc/testsuite/gcc.target/i386/pieces-memset-41.c
> index d7a27f52983..27a6c8ad139 100644
> --- a/gcc/testsuite/gcc.target/i386/pieces-memset-41.c
> +++ b/gcc/testsuite/gcc.target/i386/pieces-memset-41.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile } */
> -/* { dg-options "-O2 -mno-avx2 -mavx -mtune=sandybridge -mno-stackrealign" }
> */
> +/* { dg-options "-O2 -mno-avx2 -mavx -mprefer-vector-width=128
> -mtune=sandybridge -mno-stackrealign" } */
> /* Cope with --enable-frame-pointer. */
> /* { dg-additional-options "-fomit-frame-pointer" } */
>
> diff --git a/gcc/testsuite/gcc.target/i386/pieces-memset-42.c
> b/gcc/testsuite/gcc.target/i386/pieces-memset-42.c
> index df0c122aae7..103da699ae5 100644
> --- a/gcc/testsuite/gcc.target/i386/pieces-memset-42.c
> +++ b/gcc/testsuite/gcc.target/i386/pieces-memset-42.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile } */
> -/* { dg-options "-O2 -mno-avx2 -mavx -mtune=sandybridge" } */
> +/* { dg-options "-O2 -mno-avx2 -mavx -mprefer-vector-width=128
> -mtune=sandybridge" } */
>
> extern char *dst;
>
> diff --git a/gcc/testsuite/gcc.target/i386/pieces-memset-43.c
> b/gcc/testsuite/gcc.target/i386/pieces-memset-43.c
> index 2f2179c2df9..f1494e17610 100644
> --- a/gcc/testsuite/gcc.target/i386/pieces-memset-43.c
> +++ b/gcc/testsuite/gcc.target/i386/pieces-memset-43.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile } */
> -/* { dg-options "-O2 -mno-avx2 -mavx -mtune=sandybridge" } */
> +/* { dg-options "-O2 -mno-avx2 -mavx -mprefer-vector-width=128
> -mtune=sandybridge" } */
>
> extern char *dst;
>
> diff --git a/gcc/testsuite/gcc.target/i386/pieces-memset-51.c
> b/gcc/testsuite/gcc.target/i386/pieces-memset-51.c
> new file mode 100644
> index 00000000000..192ec0d1647
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pieces-memset-51.c
> @@ -0,0 +1,12 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mno-avx2 -mavx -mtune=generic" } */
> +
> +extern char *dst;
> +
> +void
> +foo (int x)
> +{
> + __builtin_memset (dst, x, 64);
> +}
> +
> +/* { dg-final { scan-assembler-times "vmovdqu\[ \\t\]+\[^\n\]*%ymm" 2 } } */
> diff --git a/gcc/testsuite/gcc.target/i386/pieces-strcpy-2.c
> b/gcc/testsuite/gcc.target/i386/pieces-strcpy-2.c
> index 90446edb4f3..9bb94b7419b 100644
> --- a/gcc/testsuite/gcc.target/i386/pieces-strcpy-2.c
> +++ b/gcc/testsuite/gcc.target/i386/pieces-strcpy-2.c
> @@ -1,5 +1,5 @@
> /* { dg-do compile { target { ! ia32 } } } */
> -/* { dg-options "-O2 -mno-avx2 -mavx -mtune=sandybridge" } */
> +/* { dg-options "-O2 -mno-avx2 -mavx -mprefer-vector-width=128
> -mtune=sandybridge" } */
>
> extern char *strcpy (char *, const char *);
>
> diff --git a/gcc/testsuite/gcc.target/i386/pieces-strcpy-3.c
> b/gcc/testsuite/gcc.target/i386/pieces-strcpy-3.c
> new file mode 100644
> index 00000000000..df7571b547f
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pieces-strcpy-3.c
> @@ -0,0 +1,15 @@
> +/* { dg-do compile { target { ! ia32 } } } */
> +/* { dg-options "-O2 -mno-avx2 -mavx -mtune=generic" } */
> +
> +extern char *strcpy (char *, const char *);
> +
> +void
> +foo (char *s)
> +{
> + strcpy (s,
> + "1234567890abcdef123456abcdef5678123456abcdef567abcdef678"
> + "1234567");
> +}
> +
> +/* { dg-final { scan-assembler-times "vmovdqa\[ \\t\]+\[^\n\]*%ymm" 2 } } */
> +/* { dg-final { scan-assembler-times "vmovdqu\[ \\t\]+\[^\n\]*%ymm" 2 } } */
> --
> 2.31.1
>
