S390: configure check for vector instruction support in assembler.

The S390 specific test checks if the assembler has support for the new z13
vector instructions by compiling a vector instruction. The .machine and
.machinemode directives are needed to compile the vector instruction without
-march=z13 option on 31/64 bit.
On success the macro HAVE_S390_VX_ASM_SUPPORT is defined. This macro is used
to determine if the optimized functions can be build without compile errors.
If the used assembler lacks vector support, then a warning is dumped while
configuring and only the common code functions are build.

The z13 instruction support was introduced in
"[Committed] S/390: Add support for IBM z13."
(https://sourceware.org/ml/binutils/2015-01/msg00197.html)

ChangeLog:

	* config.h.in (HAVE_S390_VX_ASM_SUPPORT): New macro undefine.
	* sysdeps/s390/configure.ac: Add test for S390 vector instruction
	assembler support.
	* sysdeps/s390/configure: Regenerated.

ChangeLog

@@ -1,3 +1,10 @@
+2015-08-26  Stefan Liebler  <stli@linux.vnet.ibm.com>
+
+	* config.h.in (HAVE_S390_VX_ASM_SUPPORT): New macro undefine.
+	* sysdeps/s390/configure.ac: Add test for S390 vector instruction
+	assembler support.
+	* sysdeps/s390/configure: Regenerated.
+
 2015-08-26  Stefan Liebler  <stli@linux.vnet.ibm.com>
 
 	* sysdeps/s390/dl-procinfo.c (_dl_s390_cap_flags): Add z13.

config.h.in

@@ -91,6 +91,9 @@
 /* Define if assembler supports AVX512.  */
 #undef  HAVE_AVX512_ASM_SUPPORT
 
+/* Define if assembler supports vector instructions on S390.  */
+#undef  HAVE_S390_VX_ASM_SUPPORT
+
 /* Define if assembler supports Intel MPX.  */
 #undef  HAVE_MPX_SUPPORT
 

sysdeps/s390/configure

@@ -104,5 +104,46 @@ if test "$enable_lock_elision" = yes && test "$libc_cv_gcc_builtin_tbegin" = no
    critic_missing="$critic_missing The used GCC has no support for __builtin_tbegin, which is needed for lock-elision on target S390."
 fi
 
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for S390 vector instruction support" >&5
+$as_echo_n "checking for S390 vector instruction support... " >&6; }
+if ${libc_cv_asm_s390_vx+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat > conftest.c <<\EOF
+void testvecinsn ()
+{
+    __asm__ (".machine \"z13\" \n\t"
+	     ".machinemode \"zarch_nohighgprs\" \n\t"
+	     "vistrbs %%v16,%%v17 \n\t"
+	     "locghie %%r1,0" : :);
+}
+EOF
+if { ac_try='${CC-cc} --shared conftest.c -o conftest.o &> /dev/null'
+  { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; } ;
+then
+  libc_cv_asm_s390_vx=yes
+else
+  libc_cv_asm_s390_vx=no
+fi
+rm -f conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_asm_s390_vx" >&5
+$as_echo "$libc_cv_asm_s390_vx" >&6; }
+
+if test "$libc_cv_asm_s390_vx" = yes ;
+then
+  $as_echo "#define HAVE_S390_VX_ASM_SUPPORT 1" >>confdefs.h
+
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: Use binutils with vector-support in order to use optimized implementations." >&5
+$as_echo "$as_me: WARNING: Use binutils with vector-support in order to use optimized implementations." >&2;}
+fi
+
+
 test -n "$critic_missing" && as_fn_error $? "
 *** $critic_missing" "$LINENO" 5

sysdeps/s390/configure.ac

@@ -36,5 +36,34 @@ if test "$enable_lock_elision" = yes && test "$libc_cv_gcc_builtin_tbegin" = no
    critic_missing="$critic_missing The used GCC has no support for __builtin_tbegin, which is needed for lock-elision on target S390."
 fi
 
+
+AC_CACHE_CHECK(for S390 vector instruction support, libc_cv_asm_s390_vx, [dnl
+cat > conftest.c <<\EOF
+void testvecinsn ()
+{
+    __asm__ (".machine \"z13\" \n\t"
+	     ".machinemode \"zarch_nohighgprs\" \n\t"
+	     "vistrbs %%v16,%%v17 \n\t"
+	     "locghie %%r1,0" : :);
+}
+EOF
+dnl
+dnl test, if assembler supports S390 vector instructions
+if AC_TRY_COMMAND([${CC-cc} --shared conftest.c -o conftest.o &> /dev/null]) ;
+then
+  libc_cv_asm_s390_vx=yes
+else
+  libc_cv_asm_s390_vx=no
+fi
+rm -f conftest* ])
+
+if test "$libc_cv_asm_s390_vx" = yes ;
+then
+  AC_DEFINE(HAVE_S390_VX_ASM_SUPPORT)
+else
+  AC_MSG_WARN([Use binutils with vector-support in order to use optimized implementations.])
+fi
+
+
 test -n "$critic_missing" && AC_MSG_ERROR([
 *** $critic_missing])