S390: Configure check for vector support in gcc.

The S390 specific test checks if the gcc has support for vector registers
by compiling an inline assembly which clobbers vector registers.
On success the macro HAVE_S390_VX_GCC_SUPPORT is defined.
This macro can be used to determine if e.g. clobbering vector registers
is allowed or not.

ChangeLog:

	* config.h.in (HAVE_S390_VX_GCC_SUPPORT): New macro undefine.
	* sysdeps/s390/configure.ac: Add test for S390 vector register
	support in gcc.
	* sysdeps/s390/configure: Regenerated.

4 files changed, 64 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index fceeeb3..cf6315a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2016-05-25  Stefan Liebler  <stli@linux.vnet.ibm.com>
 
+	* config.h.in (HAVE_S390_VX_GCC_SUPPORT): New macro undefine.
+	* sysdeps/s390/configure.ac: Add test for S390 vector register
+	support in gcc.
+	* sysdeps/s390/configure: Regenerated.
+
+2016-05-25  Stefan Liebler  <stli@linux.vnet.ibm.com>
+
 	* iconvdata/Makefile ($(inst_gconvdir)/gconv-modules):
 	Install file from $(objpfx)gconv-modules.
 	($(objpfx)gconv-modules): Concatenate architecture specific file
diff --git a/config.h.in b/config.h.in
index 2c902b0..b28b513 100644
--- a/config.h.in
+++ b/config.h.in
@@ -73,6 +73,10 @@
 /* Define if assembler supports vector instructions on S390.  */
 #undef  HAVE_S390_VX_ASM_SUPPORT
 
+/* Define if gcc supports vector registers as clobbers in inline assembly
+   on S390.  */
+#undef  HAVE_S390_VX_GCC_SUPPORT
+
 /* Define if assembler supports Intel MPX.  */
 #undef  HAVE_MPX_SUPPORT
 
diff --git a/sysdeps/s390/configure b/sysdeps/s390/configure
index 0fa54c3..c9fb69c 100644
--- a/sysdeps/s390/configure
+++ b/sysdeps/s390/configure
@@ -144,6 +144,38 @@ else
 $as_echo "$as_me: WARNING: Use binutils with vector-support in order to use optimized implementations." >&2;}
 fi
 
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for S390 vector support in gcc" >&5
+$as_echo_n "checking for S390 vector support in gcc... " >&6; }
+if ${libc_cv_gcc_s390_vx+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat > conftest.c <<\EOF
+void testvecclobber ()
+{
+  __asm__ ("" : : : "v16");
+}
+EOF
+if { ac_try='${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_gcc_s390_vx=yes
+else
+  libc_cv_gcc_s390_vx=no
+fi
+rm -f conftest*
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_gcc_s390_vx" >&5
+$as_echo "$libc_cv_gcc_s390_vx" >&6; }
+
+if test "$libc_cv_gcc_s390_vx" = yes ;
+then
+  $as_echo "#define HAVE_S390_VX_GCC_SUPPORT 1" >>confdefs.h
+
+fi
 
 test -n "$critic_missing" && as_fn_error $? "
 *** $critic_missing" "$LINENO" 5
diff --git a/sysdeps/s390/configure.ac b/sysdeps/s390/configure.ac
index 4da134e..1db6d84 100644
--- a/sysdeps/s390/configure.ac
+++ b/sysdeps/s390/configure.ac
@@ -64,6 +64,27 @@ else
   AC_MSG_WARN([Use binutils with vector-support in order to use optimized implementations.])
 fi
 
+AC_CACHE_CHECK(for S390 vector support in gcc, libc_cv_gcc_s390_vx, [dnl
+cat > conftest.c <<\EOF
+void testvecclobber ()
+{
+  __asm__ ("" : : : "v16");
+}
+EOF
+dnl
+dnl test, if gcc supports S390 vector registers as clobber in inline assembly
+if AC_TRY_COMMAND([${CC-cc} --shared conftest.c -o conftest.o &> /dev/null]) ;
+then
+  libc_cv_gcc_s390_vx=yes
+else
+  libc_cv_gcc_s390_vx=no
+fi
+rm -f conftest* ])
+
+if test "$libc_cv_gcc_s390_vx" = yes ;
+then
+  AC_DEFINE(HAVE_S390_VX_GCC_SUPPORT)
+fi
 
 test -n "$critic_missing" && AC_MSG_ERROR([
 *** $critic_missing])