aarch64: Use proper guards for NEON instructions

The zstd code assumes that if you are on aarch64, you have NEON
instructions. This is not necessarily true. In a boot loader, where
you might not have the VFP properly initialized, these instructions
may not be available. It's also an error to include arm_neon.h when
the NEON insturctions aren't enabled. Change the guards for using the
NEON instructions from __aarch64__ to __ARM_NEON which is the standard
symbol for knowing if they are available.

__ARM_NEON is the proper symbol, defined in ARM C Language Extensions
Release 2.1 (https://developer.arm.com/documentation/ihi0053/d/). Some
sources suggest __ARM_NEON__, but that's the obsolete spelling from
prior versions of the standard.

Updated based on zstd pull request https://github.com/facebook/zstd/pull/2356

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Warner Losh <imp@bsdimp.com>
Closes #11055
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Warner Losh 2020-10-13 22:01:40 -06:00 committed by GitHub
parent 92286311f8
commit 6ba2e72b78
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@ -3074,7 +3074,7 @@ size_t FSE_decompress(void* dst, size_t dstCapacity, const void* cSrc, size_t cS
/*-*************************************
* Dependencies
***************************************/
#ifdef __aarch64__
#if !defined(ZSTD_NO_INTRINSICS) && defined(__ARM_NEON)
#include <arm_neon.h>
#endif
/**** skipping file: compiler.h ****/
@ -6525,7 +6525,7 @@ static const U32 OF_defaultNormLog = OF_DEFAULTNORMLOG;
* Shared functions to include for inlining
*********************************************/
static void ZSTD_copy8(void* dst, const void* src) {
#ifdef __aarch64__
#if !defined(ZSTD_NO_INTRINSICS) && defined(__ARM_NEON)
vst1_u8((uint8_t*)dst, vld1_u8((const uint8_t*)src));
#else
memcpy(dst, src, 8);
@ -6534,7 +6534,7 @@ static void ZSTD_copy8(void* dst, const void* src) {
#define COPY8(d,s) { ZSTD_copy8(d,s); d+=8; s+=8; }
static void ZSTD_copy16(void* dst, const void* src) {
#ifdef __aarch64__
#if !defined(ZSTD_NO_INTRINSICS) && defined(__ARM_NEON)
vst1q_u8((uint8_t*)dst, vld1q_u8((const uint8_t*)src));
#else
memcpy(dst, src, 16);