Remove SSE4.2 and AVX2 toggles in favor of march=x86-64-v3

CMake/HPHPCompiler.cmake

@@ -93,19 +93,8 @@ if (${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang" OR ${CMAKE_CXX_COMPILER_ID} STREQU
   endif()
 
   if (IS_X64)
-    # For unclear reasons, our detection for what crc32 intrinsics you have
-    # will cause Apple clang to ICE. Specifying a baseline here works around
-    # the issue. (SSE4.2 has been available on processors for quite some time now.)
-    if(ENABLE_SSE4_2 OR ${CMAKE_CXX_COMPILER_ID} STREQUAL "AppleClang")
-      list(APPEND GENERAL_CXX_OPTIONS
-        # SSE4.2 has been available on processors for quite some time now. This
-        # allows enabling CRC hash function code
-        "msse4.2"
-      )
-      # Also pass the right option to ASM files to avoid inconsistencies
-      # in CRC hash function handling
-      set(CMAKE_ASM_FLAGS  "${CMAKE_ASM_FLAGS} -msse4.2")
-    endif()
+    list(APPEND GENERAL_CXX_OPTIONS "march=x86-64-v3")
+    set(CMAKE_ASM_FLAGS  "${CMAKE_ASM_FLAGS} -march=x86-64-v3")
   endif()
 
   if (${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang" OR ${CMAKE_CXX_COMPILER_ID} STREQUAL "AppleClang") # using Clang
@@ -285,13 +274,6 @@ if (${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang" OR ${CMAKE_CXX_COMPILER_ID} STREQU
     set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -${opt}")
   endforeach()
 
-  # The ASM part of this makes it more effort than it's worth
-  # to add these to the general flags system.
-  if(ENABLE_AVX2)
-    set(CMAKE_C_FLAGS    "${CMAKE_C_FLAGS} -mavx2 -march=core-avx2")
-    set(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} -mavx2 -march=core-avx2")
-    set(CMAKE_ASM_FLAGS  "${CMAKE_ASM_FLAGS} -mavx2 -march=core-avx2")
-  endif()
   # using Intel C++
 elseif (${CMAKE_CXX_COMPILER_ID} STREQUAL "Intel")
   set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS} -no-ipo -fp-model precise -wd584 -wd1418 -wd1918 -wd383 -wd869 -wd981 -wd424 -wd1419 -wd444 -wd271 -wd2259 -wd1572 -wd1599 -wd82 -wd177 -wd593 -w")
@@ -349,11 +331,6 @@ elseif (${CMAKE_CXX_COMPILER_ID} STREQUAL "MSVC")
     list(APPEND MSVC_GENERAL_OPTIONS "MP")
   endif()
 
-  # Enable AVX2 codegen if available and requested.
-  if (ENABLE_AVX2)
-    list(APPEND MSVC_GENERAL_OPTIONS "arch:AVX2")
-  endif()
-
   # Validate, and then add the favored architecture.
   if (NOT MSVC_FAVORED_ARCHITECTURE STREQUAL "blend" AND NOT MSVC_FAVORED_ARCHITECTURE STREQUAL "AMD64" AND NOT MSVC_FAVORED_ARCHITECTURE STREQUAL "INTEL64" AND NOT MSVC_FAVORED_ARCHITECTURE STREQUAL "ATOM")
     message(FATAL_ERROR "MSVC_FAVORED_ARCHITECTURE must be set to one of exactly, 'blend', 'AMD64', 'INTEL64', or 'ATOM'! Got '${MSVC_FAVORED_ARCHITECTURE}' instead!")

CMake/HPHPFindLibs.cmake

@@ -442,39 +442,14 @@ macro(hphp_link target)
     target_link_libraries(${target} ${VISIBILITY} dbghelp.lib dnsapi.lib)
   endif()
 
-# Check whether atomic operations require -latomic or not
-# See https://github.com/facebook/hhvm/issues/5217
-  include(CheckCXXSourceCompiles)
-  set(OLD_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
-  set(CMAKE_REQUIRED_FLAGS "-std=c++1y")
-  CHECK_CXX_SOURCE_COMPILES("
-#include <atomic>
-#include <iostream>
-#include <stdint.h>
-int main() {
-    struct Test { int64_t val1; int64_t val2; };
-    std::atomic<Test> s;
-    // Do this to stop modern compilers from optimizing away the libatomic
-    // calls in release builds, making this test always pass in release builds,
-    // and incorrectly think that HHVM doesn't need linking against libatomic.
-    bool (std::atomic<Test>::* volatile x)(void) const =
-      &std::atomic<Test>::is_lock_free;
-    std::cout << (s.*x)() << std::endl;
-}
-  " NOT_REQUIRE_ATOMIC_LINKER_FLAG)
-
-  if(NOT "${NOT_REQUIRE_ATOMIC_LINKER_FLAG}")
-      message(STATUS "-latomic is required to link hhvm")
-      find_library(ATOMIC_LIBRARY NAMES atomic libatomic.so.1)
-      if (ATOMIC_LIBRARY STREQUAL "ATOMIC_LIBRARY-NOTFOUND")
-        # -latomic should be available for gcc even when libatomic.so.1 is not
-        # in the library search path
-        target_link_libraries(${target} ${VISIBILITY} atomic)
-      else()
-        target_link_libraries(${target} ${VISIBILITY} ${ATOMIC_LIBRARY})
-      endif()
-  endif()
-  set(CMAKE_REQUIRED_FLAGS ${OLD_CMAKE_REQUIRED_FLAGS})
+  find_library(ATOMIC_LIBRARY NAMES atomic libatomic.so.1)
+  if (ATOMIC_LIBRARY STREQUAL "ATOMIC_LIBRARY-NOTFOUND")
+    # -latomic should be available for gcc even when libatomic.so.1 is not
+    # in the library search path
+    target_link_libraries(${target} ${VISIBILITY} atomic)
+  else()
+    target_link_libraries(${target} ${VISIBILITY} ${ATOMIC_LIBRARY})
+  endif()
 
   if (ENABLE_XED)
     if (LibXed_FOUND)

CMake/Options.cmake

@@ -3,10 +3,8 @@
 option(ALWAYS_ASSERT "Enabled asserts in a release build" OFF)
 option(ENABLE_SSP "Enabled GCC/LLVM stack-smashing protection" OFF)
 option(STATIC_CXX_LIB "Statically link libstd++ and libgcc." OFF)
-option(ENABLE_AVX2 "Enable the use of AVX2 instructions" OFF)
 option(ENABLE_AARCH64_CRC "Enable the use of CRC instructions" OFF)
 option(ENABLE_FASTCGI "Enable the FastCGI interface." ON)
-option(ENABLE_SSE4_2 "Enable SSE4.2 supported code." OFF)
 
 option(EXECUTION_PROFILER "Enable the execution profiler" OFF)
 
@@ -44,7 +42,7 @@ option(ENABLE_PROXYGEN_SERVER "Build the Proxygen HTTP server" ON)
 option(ENABLE_SPLIT_DWARF "Reduce linker memory usage by putting debugging information into .dwo files" OFF)
 
 IF (LINUX)
-    option(MAP_TEXT_HUGE_PAGES "Remap hot static code onto huge pages" ON)
+  option(MAP_TEXT_HUGE_PAGES "Remap hot static code onto huge pages" ON)
 ENDIF()
 
 IF (NOT DEFAULT_CONFIG_DIR)

CMakeLists.txt

@@ -63,7 +63,7 @@ if(NOT SKIP_CCACHE)
       message(STATUS "Found ccache: ${CCACHE_FOUND} - enabling ccache as compiler wrapper")
     else()
       message(STATUS "Found ccache - ccache already in use as C and/or CXX compiler wrapper")
-   endif()
+    endif()
   endif(CCACHE_FOUND)
 endif(NOT SKIP_CCACHE)
 

hphp/util/hphp-config.h.in

@@ -39,11 +39,9 @@
  */
 
 #ifdef USE_CMAKE
-#cmakedefine ENABLE_AVX2 1
 #cmakedefine ENABLE_AARCH64_CRC 1
 #cmakedefine EXECUTION_PROFILER 1
 #else
-/* #undef ENABLE_AVX2 */
 /* #undef ENABLE_AARCH64_CRC */
 /* #undef EXECUTION_PROFILER */
 #endif

hphp/util/memset-x64-avx2.S

@@ -101,7 +101,7 @@ ETCH_LABEL(more_than_63bytes):
 	addq	%rax, %rcx
 	subq	%rax, %rdx
 	je		ETCH_LABEL(EXIT_MEMSET)
-	
+
 ETCH_ALIGN8
 ETCH_ALIGN4
 ETCH_LABEL(128byte_loop_data_guzzler):

third-party/folly/CMakeLists.txt

@@ -27,13 +27,6 @@ get_filename_component(BOOST_LIBRARY_DIR "${FIRST_LIB}" DIRECTORY)
 set(FOLLY_CXXFLAGS "-I${JEMALLOC_INCLUDE_DIR} -I${CMAKE_CURRENT_LIST_DIR}/include")
 message(STATUS "FOLLY_CXXFLAGS: ${FOLLY_CXXFLAGS}")
 
-if(ENABLE_SSE4_2 OR ${CMAKE_CXX_COMPILER_ID} STREQUAL "AppleClang")
-  if(IS_X64)
-    message(STATUS "Enabling SSE 4.2 for bundled folly")
-    set(FOLLY_CXXFLAGS "${FOLLY_CXXFLAGS} -msse4.2")
-  endif()
-endif()
-
 ExternalProject_add(
   bundled_folly
   SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/src/