armv8 AArch64 does not require -mfpu=neon

-mpfu is not required on AArch64 / armv8 architecture on Linux and throws an error if present.
This PR has been tested on gcc and clang on Gentoo-64 and Raspian-64 on a Raspberry Pi 4,
as well as with a cross from Ubuntu
(`make clean && make -j build ARCH=armv8         COMP=gcc COMPILER=aarch64-linux-gnu-g++`)

fixes https://github.com/official-stockfish/Stockfish/issues/3056
closes https://github.com/official-stockfish/Stockfish/pull/3059

No functional change

diff --git a/src/Makefile b/src/Makefile
index 74ef87b94ed0da554e6a152a878daab1ec697014..3e1b7c351bc4dd5e7d90ea25f2c5c3202488d55d 100644 (file)
--- a/src/Makefile
+++ b/src/Makefile
@@ -241,7 +241,7 @@ ifeq ($(ARCH),armv7-neon)
 endif
 
 ifeq ($(ARCH),armv8)
-       arch = armv8-a
+       arch = armv8
        prefetch = yes
        popcnt = yes
        neon = yes
@@ -285,7 +285,7 @@ ifeq ($(COMP),gcc)
        CXX=g++
        CXXFLAGS += -pedantic -Wextra -Wshadow
 
-       ifeq ($(arch),$(filter $(arch),armv7 armv8-a))
+       ifeq ($(arch),$(filter $(arch),armv7 armv8))
                ifeq ($(OS),Android)
                        CXXFLAGS += -m$(bits)
                        LDFLAGS += -m$(bits)
@@ -387,7 +387,7 @@ ifeq ($(COMP),ndk)
                CXXFLAGS += -mthumb -march=armv7-a -mfloat-abi=softfp -mfpu=neon
                STRIP=arm-linux-androideabi-strip
        endif
-       ifeq ($(arch),armv8-a)
+       ifeq ($(arch),armv8)
                comp=aarch64-linux-android21-clang
                CXX=aarch64-linux-android21-clang++
                STRIP=aarch64-linux-android-strip
@@ -476,7 +476,7 @@ endif
 
 ### 3.6 popcnt
 ifeq ($(popcnt),yes)
-       ifeq ($(arch),$(filter $(arch),ppc64 armv7 armv8-a arm64))
+       ifeq ($(arch),$(filter $(arch),ppc64 armv7 armv8 arm64))
                CXXFLAGS += -DUSE_POPCNT
        else ifeq ($(comp),icc)
                CXXFLAGS += -msse3 -DUSE_POPCNT
@@ -539,9 +539,11 @@ ifeq ($(neon),yes)
        CXXFLAGS += -DUSE_NEON
        ifeq ($(KERNEL),Linux)
        ifneq ($(COMP),ndk)
+       ifneq ($(arch),armv8)
                CXXFLAGS += -mfpu=neon
        endif
        endif
+       endif
 endif
 
 ### 3.7 pext
@@ -780,7 +782,7 @@ config-sanity:
        @test "$(optimize)" = "yes" || test "$(optimize)" = "no"
        @test "$(arch)" = "any" || test "$(arch)" = "x86_64" || test "$(arch)" = "i386" || \
         test "$(arch)" = "ppc64" || test "$(arch)" = "ppc" || \
-        test "$(arch)" = "armv7" || test "$(arch)" = "armv8-a" || test "$(arch)" = "arm64"
+        test "$(arch)" = "armv7" || test "$(arch)" = "armv8" || test "$(arch)" = "arm64"
        @test "$(bits)" = "32" || test "$(bits)" = "64"
        @test "$(prefetch)" = "yes" || test "$(prefetch)" = "no"
        @test "$(popcnt)" = "yes" || test "$(popcnt)" = "no"