[PATCH][GCC] aarch64: Add LS64 extension and intrinsics

[Przemyslaw Wirkus via Gcc-patches]

Hi,

This patch is adding support for LS64 (Armv8.7-A Load/Store 64 Byte extension)
which is part of Armv8.7-A architecture. Changes include missing plumbing for
TARGET_LS64, LS64 data structure and intrinsics defined in ACLE [0]. Machine
description of intrinsics is using new V8DI mode added in a separate patch.
__ARM_FEATURE_LS64 is defined if the Armv8.7-A LS64 instructions for atomic
64-byte access to device memory are supported.

New compiler internal type is added wrapping ACLE struct data512_t [0]:

typedef struct {
  uint64_t val[8];
} __arm_data512_t;

Please note that command line support for this feature was already added [1].

  [0] 
https://github.com/ARM-software/acle/blob/main/main/acle.rst#load-store-64-byte-intrinsics
  [1] commit e159c0aa10e50c292a534535c73f38d22b6129a8 (AArch64: Add command-line
      support for Armv8.7-a)

For below C code see example snippets of generated code:

#include <arm_acle.h>

void
func(const void * addr, data512_t *data) {
  *data = __arm_ld64b (addr);
}

func:
        ld64b   x8, [x0]
        stp     x8, x9, [x1]
        sub     sp, sp, #64
        stp     x10, x11, [x1, 16]
        stp     x12, x13, [x1, 32]
        stp     x14, x15, [x1, 48]
        add     sp, sp, 64
        ret
~~~

#include <arm_acle.h>

uint64_t
func(void *addr, data512_t value) {
    return  __arm_st64bv (addr, value);
}

func:
        ldp     x8, x9, [x1]
        ldp     x10, x11, [x1, 16]
        ldp     x12, x13, [x1, 32]
        ldp     x14, x15, [x1, 48]
        st64bv  x1, x8, [x0]
        mov     x0, x1
        ret

~~~

uint64_t
ls64_store_v0(const data512_t *input, void *addr)
{
    uint64_t status;
    __asm__ volatile ("st64bv0 %0, %2, [%1]"
                      : "=r" (status), "=r" (addr)
                      : "r" (*input)
                      : "memory");
    return status;
}

ls64_store_v0:
        ldp     x8, x9, [x0]
        ldp     x10, x11, [x0, 16]
        ldp     x12, x13, [x0, 32]
        ldp     x14, x15, [x0, 48]
        st64bv0 x0, x8, [x1]
        ret

Regtested on aarch64-elf cross and no issues.

OK for master?

gcc/ChangeLog:

2021-11-11  Przemyslaw Wirkus  <przemyslaw.wir...@arm.com>

        * config/aarch64/aarch64-builtins.c (enum aarch64_builtins):
        Define AARCH64_LS64_BUILTIN_LD64B, AARCH64_LS64_BUILTIN_ST64B,
        AARCH64_LS64_BUILTIN_ST64BV, AARCH64_LS64_BUILTIN_ST64BV0.
        (aarch64_init_ls64_builtin_decl): Helper function.
        (aarch64_init_ls64_builtins): Helper function.
        (aarch64_init_ls64_builtins_types): Helper function.
        (aarch64_general_init_builtins): Init LS64 intrisics for
        TARGET_LS64.
        (aarch64_expand_builtin_ls64): LS64 intrinsics expander.
        (aarch64_general_expand_builtin): Handle aarch64_expand_builtin_ls64.
        (ls64_builtins_data): New helper struct.
        (v8di_UP): New define.
        * config/aarch64/aarch64-c.c (aarch64_update_cpp_builtins): Define
        __ARM_FEATURE_LS64.
        * config/aarch64/aarch64.h (AARCH64_ISA_LS64): New define.
        (AARCH64_ISA_V8_7): New define.
        (TARGET_LS64): New define.
        * config/aarch64/aarch64.md: Add UNSPEC_LD64B, UNSPEC_ST64B,
        UNSPEC_ST64BV and UNSPEC_ST64BV0.
        (ld64b): New define_insn.
        (st64b): New define_insn.
        (st64bv): New define_insn.
        (st64bv0): New define_insn.
        * config/aarch64/arm_acle.h (target):
        (data512_t): New type derived from __arm_data512_t.
        (__arm_data512_t): New internal type.
        (__arm_ld64b): New intrinsic.
        (__arm_st64b): New intrinsic.
        (__arm_st64bv): New intrinsic.
        (__arm_st64bv0): New intrinsic.
        * config/arm/types.md: Add new type ls64.

gcc/testsuite/ChangeLog:

2021-11-11  Przemyslaw Wirkus  <przemyslaw.wir...@arm.com>

        * gcc.target/aarch64/acle/ls64_asm.c: New test.
        * gcc.target/aarch64/acle/ls64_ld64b-2.c: New test.
        * gcc.target/aarch64/acle/ls64_ld64b.c: New test.
        * gcc.target/aarch64/acle/ls64_st64b.c: New test.
        * gcc.target/aarch64/acle/ls64_st64bv-2.c: New test.
        * gcc.target/aarch64/acle/ls64_st64bv.c: New test.
        * gcc.target/aarch64/acle/ls64_st64bv0-2.c: New test.
        * gcc.target/aarch64/acle/ls64_st64bv0.c: New test.
        * gcc.target/aarch64/pragma_cpp_predefs_2.c: Add checks
        for __ARM_FEATURE_LS64.

rb14982.patch
Description: rb14982.patch