From d4358ddba7184aa7403d12397f2f49f5ea6364fd Mon Sep 17 00:00:00 2001
From: Mathias Parnaudeau <mparnaudeau@optimum-software.fr>
Date: Sat, 5 Oct 2024 15:28:39 +0200
Subject: [PATCH] Add autodetection of ppc64 architectures

That allows 'make -j profile-build' work on ppc64 architectures, setting the use of
the appropriate SIMD extension, Altivec or VSX.
For VSX, gcc allows to map SSE2 intrinsics and get benefit of the existing SIMD code.

On PowerMac G5, using altivec provides a performance improvement of 30%.
On Talos 2, using vsx provides a performance improvement of 120%.

closes https://github.com/official-stockfish/Stockfish/pull/5624

No functional change
---
 AUTHORS                          |  1 +
 scripts/get_native_properties.sh | 18 ++++++++++++++
 src/Makefile                     | 42 ++++++++++++++++++++++++++++++--
 3 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/AUTHORS b/AUTHORS
index 725b3569..31a64c17 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -143,6 +143,7 @@ Maciej Żenczykowski (zenczykowski)
 Malcolm Campbell (xoto10)
 Mark Tenzer (31m059)
 marotear
+Mathias Parnaudeau (mparnaudeau)
 Matt Ginsberg (mattginsberg)
 Matthew Lai (matthewlai)
 Matthew Sullivan (Matt14916)
diff --git a/scripts/get_native_properties.sh b/scripts/get_native_properties.sh
index dfbfac0e..ed5fc9af 100755
--- a/scripts/get_native_properties.sh
+++ b/scripts/get_native_properties.sh
@@ -54,6 +54,20 @@ set_arch_x86_64() {
   fi
 }
 
+set_arch_ppc_64() {
+  if $(grep -q -w "altivec" /proc/cpuinfo); then
+    power=$(grep -oP -m 1 'cpu\t+: POWER\K\d+' /proc/cpuinfo)
+    if [ "0$power" -gt 7 ]; then
+      # VSX started with POWER8
+      true_arch='ppc-64-vsx'
+    else
+      true_arch='ppc-64-altivec'
+    fi
+  else
+    true_arch='ppc-64'
+  fi
+}
+
 # Check the system type
 uname_s=$(uname -s)
 uname_m=$(uname -m)
@@ -87,6 +101,10 @@ case $uname_s in
         file_os='ubuntu'
         true_arch='x86-32'
         ;;
+      'ppc64'*)
+        file_os='ubuntu'
+        set_arch_ppc_64
+        ;;
       'aarch64')
         file_os='android'
         true_arch='armv8'
diff --git a/src/Makefile b/src/Makefile
index 6cb778a6..15066781 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -98,6 +98,8 @@ VPATH = syzygy:nnue:nnue/features
 # avx512 = yes/no     --- -mavx512bw         --- Use Intel Advanced Vector Extensions 512
 # vnni256 = yes/no    --- -mavx256vnni       --- Use Intel Vector Neural Network Instructions 512 with 256bit operands
 # vnni512 = yes/no    --- -mavx512vnni       --- Use Intel Vector Neural Network Instructions 512
+# altivec = yes/no    --- -maltivec          --- Use PowerPC Altivec SIMD extension
+# vsx = yes/no        --- -mvsx              --- Use POWER VSX SIMD extension
 # neon = yes/no       --- -DUSE_NEON         --- Use ARM SIMD architecture
 # dotprod = yes/no    --- -DUSE_NEON_DOTPROD --- Use ARM advanced SIMD Int8 dot product instructions
 # lsx = yes/no        --- -mlsx              --- Use Loongson SIMD eXtension
@@ -126,7 +128,7 @@ endif
 ifeq ($(ARCH), $(filter $(ARCH), \
                  x86-64-vnni512 x86-64-vnni256 x86-64-avx512 x86-64-avxvnni x86-64-bmi2 \
                  x86-64-avx2 x86-64-sse41-popcnt x86-64-modern x86-64-ssse3 x86-64-sse3-popcnt \
-                 x86-64 x86-32-sse41-popcnt x86-32-sse2 x86-32 ppc-64 ppc-32 e2k \
+                 x86-64 x86-32-sse41-popcnt x86-32-sse2 x86-32 ppc-64 ppc-64-altivec ppc-64-vsx ppc-32 e2k \
                  armv7 armv7-neon armv8 armv8-dotprod apple-silicon general-64 general-32 riscv64 \
                  loongarch64 loongarch64-lsx loongarch64-lasx))
    SUPPORTED_ARCH=true
@@ -151,6 +153,8 @@ avxvnni = no
 avx512 = no
 vnni256 = no
 vnni512 = no
+altivec = no
+vsx = no
 neon = no
 dotprod = no
 arm_version = 0
@@ -360,6 +364,20 @@ ifeq ($(ARCH),ppc-64)
 	prefetch = yes
 endif
 
+ifeq ($(ARCH),ppc-64-altivec)
+	arch = ppc64
+	popcnt = yes
+	prefetch = yes
+	altivec = yes
+endif
+
+ifeq ($(ARCH),ppc-64-vsx)
+	arch = ppc64
+	popcnt = yes
+	prefetch = yes
+	vsx = yes
+endif
+
 ifeq ($(findstring e2k,$(ARCH)),e2k)
 	arch = e2k
 	mmx = yes
@@ -650,7 +668,7 @@ else
 endif
 
 ifeq ($(popcnt),yes)
-	ifeq ($(arch),$(filter $(arch),ppc64 armv7 armv8 arm64))
+	ifeq ($(arch),$(filter $(arch),ppc64 ppc64-altivec ppc64-vsx armv7 armv8 arm64))
 		CXXFLAGS += -DUSE_POPCNT
 	else
 		CXXFLAGS += -msse3 -mpopcnt -DUSE_POPCNT
@@ -720,6 +738,20 @@ ifeq ($(mmx),yes)
 	endif
 endif
 
+ifeq ($(altivec),yes)
+	CXXFLAGS += -maltivec
+	ifeq ($(COMP),gcc)
+		CXXFLAGS += -mabi=altivec
+	endif
+endif
+
+ifeq ($(vsx),yes)
+	CXXFLAGS += -mvsx
+	ifeq ($(COMP),gcc)
+		CXXFLAGS += -DNO_WARN_X86_INTRINSICS -DUSE_SSE2
+	endif
+endif
+
 ifeq ($(neon),yes)
 	CXXFLAGS += -DUSE_NEON=$(arm_version)
 	ifeq ($(KERNEL),Linux)
@@ -852,6 +884,8 @@ help:
 	@echo "x86-32-sse2             > x86 32-bit with sse2 support"
 	@echo "x86-32                  > x86 32-bit generic (with mmx compile support)"
 	@echo "ppc-64                  > PPC 64-bit"
+	@echo "ppc-64-altivec          > PPC 64-bit with altivec support"
+	@echo "ppc-64-vsx              > PPC 64-bit with vsx support"
 	@echo "ppc-32                  > PPC 32-bit"
 	@echo "armv7                   > ARMv7 32-bit"
 	@echo "armv7-neon              > ARMv7 32-bit with popcnt and neon"
@@ -987,6 +1021,8 @@ config-sanity: net
 	@echo "avx512: '$(avx512)'"
 	@echo "vnni256: '$(vnni256)'"
 	@echo "vnni512: '$(vnni512)'"
+	@echo "altivec: '$(altivec)'"
+	@echo "vsx: '$(vsx)'"
 	@echo "neon: '$(neon)'"
 	@echo "dotprod: '$(dotprod)'"
 	@echo "arm_version: '$(arm_version)'"
@@ -1020,6 +1056,8 @@ config-sanity: net
 	@test "$(avx512)" = "yes" || test "$(avx512)" = "no"
 	@test "$(vnni256)" = "yes" || test "$(vnni256)" = "no"
 	@test "$(vnni512)" = "yes" || test "$(vnni512)" = "no"
+	@test "$(altivec)" = "yes" || test "$(altivec)" = "no"
+	@test "$(vsx)" = "yes" || test "$(vsx)" = "no"
 	@test "$(neon)" = "yes" || test "$(neon)" = "no"
 	@test "$(lsx)" = "yes" || test "$(lsx)" = "no"
 	@test "$(lasx)" = "yes" || test "$(lasx)" = "no"