S/390: Use getauxval to fix #560

Author: Andreas-Krebbel

src/libm/CMakeLists.txt

@@ -833,12 +833,6 @@ if (SLEEF_ARCH_S390X)
   add_dependencies(disps390x_128_obj disps390x_128.c_generated renamedsp128.h_generated ${TARGET_HEADERS})
   target_sources(${TARGET_LIBSLEEF} PRIVATE $<TARGET_OBJECTS:disps390x_128_obj>)
 
-  if(COMPILER_SUPPORTS_VXE2)
-    add_library(tryvxe2_obj OBJECT tryvxe2.c)
-    target_compile_options(tryvxe2_obj PRIVATE ${FLAGS_ENABLE_VXE2})
-    set_target_properties(tryvxe2_obj PROPERTIES ${COMMON_TARGET_PROPERTIES})
-    target_sources(${TARGET_LIBSLEEF} PRIVATE $<TARGET_OBJECTS:tryvxe2_obj>)
-  endif()
 endif(SLEEF_ARCH_S390X)
 
 # --------------------------------------------------------------------

src/libm/disps390x_128.c.org

@@ -7,6 +7,7 @@
 #include <assert.h>
 #include <signal.h>
 #include <setjmp.h>
+#include <sys/auxv.h>
 
 #include "misc.h"
 
@@ -15,9 +16,15 @@
 
 #include "dispatcher.h"
 
+static int cpuSupportsVXE2() {
+  static int ret = -1;
+  if (ret == -1)
+    ret = !!(getauxval(AT_HWCAP) & HWCAP_S390_VXRS_EXT2);
+  return ret;
+}
+
 #ifdef ENABLE_VXE2
-void sleef_tryVXE2();
-#define SUBST_IF_EXT1(funcvxe2) if (cpuSupportsExt(sleef_tryVXE2)) p = funcvxe2;
+#define SUBST_IF_EXT1(funcvxe2) if (cpuSupportsVXE2()) p = funcvxe2;
 #else
 #define SUBST_IF_EXT1(funcvxe2)
 #endif