Merge pull request #3943 from martin-frbg/llvm15

Add clang option to avoid running out of registers in AVX512 assembly

Author: martin-frbg

cmake/system.cmake

@@ -172,9 +172,9 @@ if (DEFINED TARGET)
         endif()
     elseif (${CMAKE_C_COMPILER_ID} STREQUAL "Clang" OR ${CMAKE_C_COMPILER_ID} STREQUAL "AppleClang")
          if (${CMAKE_C_COMPILER_VERSION} VERSION_GREATER 8.99)
-          set (KERNEL_DEFINITIONS "${KERNEL_DEFINITIONS} -march=cooperlake")
+          set (KERNEL_DEFINITIONS "${KERNEL_DEFINITIONS} -march=cooperlake -exhaustive-register-search")
         else()
-          set (KERNEL_DEFINITIONS "${KERNEL_DEFINITIONS} -march=skylake-avx512")
+          set (KERNEL_DEFINITIONS "${KERNEL_DEFINITIONS} -march=skylake-avx512 -exhaustive-register-search")
         endif()
     endif()    
   endif()
@@ -188,14 +188,17 @@ if (DEFINED TARGET)
         endif()
     elseif (${CMAKE_C_COMPILER_ID} STREQUAL "Clang" OR ${CMAKE_C_COMPILER_ID} STREQUAL "AppleClang")
          if (${CMAKE_C_COMPILER_VERSION} VERSION_GREATER 12.0)
-          set (KERNEL_DEFINITIONS "${KERNEL_DEFINITIONS} -march=sapphirerapids")
+          set (KERNEL_DEFINITIONS "${KERNEL_DEFINITIONS} -march=sapphirerapids -exhaustive-register-search")
         else()
-          set (KERNEL_DEFINITIONS "${KERNEL_DEFINITIONS} -march=skylake-avx512")
+          set (KERNEL_DEFINITIONS "${KERNEL_DEFINITIONS} -march=skylake-avx512 -exhaustive-register-search")
         endif()
     endif()    
   endif()
   if (${TARGET} STREQUAL SKYLAKEX AND NOT NO_AVX512)
     	  set (KERNEL_DEFINITIONS "${KERNEL_DEFINITIONS} -march=skylake-avx512")
+  	  if (${CMAKE_C_COMPILER_ID} STREQUAL "Clang" OR ${CMAKE_C_COMPILER_ID} STREQUAL "AppleClang")
+	 	set (KERNEL_DEFINITIONS "${KERNEL_DEFINITIONS} -exhaustive-register-search")
+  	  endif()
   endif()
 
   if (((${TARGET} STREQUAL ZEN) AND HAVE_AVX512VL) AND NOT NO_AVX512)
@@ -212,6 +215,7 @@ if (DEFINED TARGET)
 	else()
     	  set (KERNEL_DEFINITIONS "${KERNEL_DEFINITIONS} -march=skylake-avx512")
         endif()
+	set (KERNEL_DEFINITIONS "${KERNEL_DEFINITIONS} -exhaustive-register-search")
     endif()
   endif()