Re: [PATCH] Add support for missing AVX512* ISAs (PR target/89929).

[H.J. Lu]

On Thu, Apr 11, 2019 at 1:38 AM Martin Liška <mli...@suse.cz> wrote:
>
> Hi.
>
> The patch is adding missing AVX512 ISAs for target and target_clone
> attributes.
>
> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
>
> Ready to be installed?
> Thanks,
> Martin
>
> gcc/ChangeLog:
>
> 2019-04-10  Martin Liska  <mli...@suse.cz>
>
>         PR target/89929
>         * config/i386/i386.c (get_builtin_code_for_version): Add
>         support for missing AVX512 ISAs.
>
> gcc/testsuite/ChangeLog:
>
> 2019-04-10  Martin Liska  <mli...@suse.cz>
>
>         PR target/89929
>         * g++.target/i386/mv28.C: New test.
>         * gcc.target/i386/mvc14.c: New test.
> ---
>  gcc/config/i386/i386.c                | 34 ++++++++++++++++++++++++++-
>  gcc/testsuite/g++.target/i386/mv28.C  | 30 +++++++++++++++++++++++
>  gcc/testsuite/gcc.target/i386/mvc14.c | 16 +++++++++++++
>  3 files changed, 79 insertions(+), 1 deletion(-)
>  create mode 100644 gcc/testsuite/g++.target/i386/mv28.C
>  create mode 100644 gcc/testsuite/gcc.target/i386/mvc14.c
>
>

Since any ISAs beyond AVX512F may be enabled individually, we
can't simply assign priorities to them.   For GFNI, we can have

1. GFNI
2.  GFNI + AVX
3.  GFNI + AVX512F
4. GFNI + AVX512F + AVX512VL

For this code,  GFNI + AVX512BW is ignored:

[hjl@gnu-cfl-1 pr89929]$ cat z.ii
__attribute__((target("gfni")))
int foo(int i) {
        return 1;
}
__attribute__((target("gfni,avx512bw")))
int foo(int i) {
        return 4;
}
__attribute__((target("default")))
int foo(int i) {
        return 3;
}
int bar ()
{
        return foo(2);
}
[hjl@gnu-cfl-1 pr89929]$
/export/build/gnu/tools-build/gcc-wip-debug/build-x86_64-linux/gcc/xgcc
-B/export/build/gnu/tools-build/gcc-wip-debug/build-x86_64-linux/gcc/
-S z.ii -O2
[hjl@gnu-cfl-1 pr89929]$ cat z.s
        .file "z.ii"
        .text
        .p2align 4
        .globl _Z3fooi.gfni
        .type _Z3fooi.gfni, @function
_Z3fooi.gfni:
.LFB0:
        .cfi_startproc
        movl $1, %eax
        ret
        .cfi_endproc
.LFE0:
        .size _Z3fooi.gfni, .-_Z3fooi.gfni
        .p2align 4
        .globl _Z3fooi
        .type _Z3fooi, @function
_Z3fooi:
.LFB2:
        .cfi_startproc
        movl $3, %eax
        ret
        .cfi_endproc
.LFE2:
        .size _Z3fooi, .-_Z3fooi
        .p2align 4
        .globl _Z3fooi.avx512bw_gfni
        .type _Z3fooi.avx512bw_gfni, @function
_Z3fooi.avx512bw_gfni:
.LFB1:
        .cfi_startproc
        movl $4, %eax
        ret
        .cfi_endproc
.LFE1:
        .size _Z3fooi.avx512bw_gfni, .-_Z3fooi.avx512bw_gfni
        .section .text._Z3fooi.resolver,"axG",@progbits,_Z3fooi.resolver,comdat
        .p2align 4
        .weak _Z3fooi.resolver
        .type _Z3fooi.resolver, @function
_Z3fooi.resolver:
.LFB5:
        .cfi_startproc
        subq $8, %rsp
        .cfi_def_cfa_offset 16
        call __cpu_indicator_init
        movl $_Z3fooi, %eax
        movl $_Z3fooi.gfni, %edx
        testb $1, __cpu_features2(%rip)
        cmovne %rdx, %rax
        addq $8, %rsp
        .cfi_def_cfa_offset 8
        ret
        .cfi_endproc
.LFE5:
        .size _Z3fooi.resolver, .-_Z3fooi.resolver
        .globl _Z7_Z3fooii
        .type _Z7_Z3fooii, @gnu_indirect_function
        .set _Z7_Z3fooii,_Z3fooi.resolver
        .text
        .p2align 4
        .globl _Z3barv
        .type _Z3barv, @function
_Z3barv:
.LFB3:
        .cfi_startproc
        movl $2, %edi
        jmp _Z7_Z3fooii
        .cfi_endproc
.LFE3:
        .size _Z3barv, .-_Z3barv
        .ident "GCC: (GNU) 9.0.1 20190411 (experimental)"
        .section .note.GNU-stack,"",@progbits
[hjl@gnu-cfl-1 pr89929]$

For AVX512 ISAs, we need a different scheme for priorities.


-- 
H.J.