cmake: aarch64: Defaults to a generic cpu target

This is equivalent to setting -mtune=generic -march=armv8-a. This ensures no implementation specific tuning, or architectural features beyond armv8-a are used,for portability across AArch64 systems.The DNNL_ARCH_OPT_FLAGS build option can be used to override these defaults to optimise for a specific cpu, or revision of the Armv8 architecture.
oneapi-src · Nov 18, 2023 · 8829c24 · 8829c24
1 parent 3e15c61
commit 8829c24
Showing 1 changed file with 12 additions and 4 deletions.
diff --git a/cmake/platform.cmake b/cmake/platform.cmake
@@ -210,9 +210,13 @@ elseif(UNIX OR MINGW)
              if (NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
                  set(DEF_ARCH_OPT_FLAGS "-O3")
              endif()
-             # For native compilation tune for the host processor
              if (CMAKE_SYSTEM_PROCESSOR STREQUAL CMAKE_HOST_SYSTEM_PROCESSOR)
-                 append(DEF_ARCH_OPT_FLAGS "-mcpu=native")
+                 # Defaults to a generic cpu target, equivalent to setting -mtune=generic -march=armv8-a.
+                 # This ensures no implementation specific tuning, or architectural features beyond
+                 # armv8-a are used, for portability across AArch64 systems.
+                 # The DNNL_ARCH_OPT_FLAGS build option can be used to override these defaults
+                 # to optimise for a specific cpu, or revision of the Armv8 architecture.
+                 append(DEF_ARCH_OPT_FLAGS "-mcpu=generic")
              endif()
         elseif(DNNL_TARGET_ARCH STREQUAL "PPC64")
              if (NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
@@ -307,9 +311,13 @@ elseif(UNIX OR MINGW)
             if (NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
                 set(DEF_ARCH_OPT_FLAGS "-O3")
             endif()
-            # For native compilation tune for the host processor
             if (CMAKE_SYSTEM_PROCESSOR STREQUAL CMAKE_HOST_SYSTEM_PROCESSOR)
-                append(DEF_ARCH_OPT_FLAGS "-mcpu=native")
+                 # Defaults to a generic cpu target, equivalent to setting -mtune=generic -march=armv8-a.
+                 # This ensures no implementation specific tuning, or architectural features beyond
+                 # armv8-a are used, for portability across AArch64 systems.
+                 # The DNNL_ARCH_OPT_FLAGS build option can be used to override these defaults
+                 # to optimise for a specific cpu, or revision of the Armv8 architecture.
+                 append(DEF_ARCH_OPT_FLAGS "-mcpu=generic")
             endif()
         elseif(DNNL_TARGET_ARCH STREQUAL "PPC64")
             if (NOT CMAKE_BUILD_TYPE STREQUAL "Debug")