re PR target/70381 (On powerpc, -mfloat128 is on by default for all VSX systems)

[gcc]
2016-04-11  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/70381
	* config/rs6000/rs6000.c (rs6000_opt_masks): Disable using the
	target attribute and pragma from changing the -mfloat128
	and -mfloat128-hardware options.

	* doc/extend.texi (Additional Floating Types): Document PowerPC
	__float128 restrictions.

[libgcc]
2016-04-11  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/70381
	* configure.ac (powerpc*-*-linux*): Rework tests to build
	__float128 emulation routines to not depend on using #pragma GCC
	target to enable -mfloat128.
	* configure: Regnerate.

[gcc/testsuite]
2016-04-11  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/70381
	* gcc.target/powerpc/float128-1.c: New tests to make sure the
	__float128 emulator is built and runs.
	* gcc.target/powerpc/float128-1.c: Likewise.

	* lib/target-supports.exp (check_ppc_float128_sw_available):
	Rework tests for __float128 software and hardware
	availability. Fix exit condition to return 0 on success.

From-SVN: r234884

3 files changed, 32 insertions, 16 deletions

diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index 6011d2c..2a13862 100644
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,11 @@
+2016-04-11  Michael Meissner  <meissner@linux.vnet.ibm.com>
+
+	PR target/70381
+	* configure.ac (powerpc*-*-linux*): Rework tests to build
+	__float128 emulation routines to not depend on using #pragma GCC
+	target to enable -mfloat128.
+	* configure: Regnerate.
+
 2016-04-04  Eric Botcazou  <ebotcazou@adacore.com>
 
 	PR target/67172
diff --git a/libgcc/configure b/libgcc/configure
index f3f3605..e7d6c75 100644
--- a/libgcc/configure
+++ b/libgcc/configure
@@ -4767,16 +4767,20 @@ esac
 esac
 
 case ${host} in
+# At present, we cannot turn -mfloat128 on via #pragma GCC target,
+# so just check if we have VSX (ISA 2.06) support to build the
+# software libraries, and whether the assembler can handle xsaddqp
+# for hardware support.
 powerpc*-*-linux*)
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the PowerPC compiler can do __float128" >&5
-$as_echo_n "checking whether the PowerPC compiler can do __float128... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for PowerPC ISA 2.06 to build __float128 libraries" >&5
+$as_echo_n "checking for PowerPC ISA 2.06 to build __float128 libraries... " >&6; }
 if test "${libgcc_cv_powerpc_float128+set}" = set; then :
   $as_echo_n "(cached) " >&6
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#pragma GCC target ("vsx,float128")
-     __float128 add (__float128 *a) { return *a + *(a+1); }
+#pragma GCC target ("vsx")
+     vector double dadd (vector double a, vector double b) { return a + b; }
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
   libgcc_cv_powerpc_float128=yes
@@ -4788,21 +4792,21 @@ fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $libgcc_cv_powerpc_float128" >&5
 $as_echo "$libgcc_cv_powerpc_float128" >&6; }
 
-  { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the PowerPC compiler can do hardware __float128" >&5
-$as_echo_n "checking whether the PowerPC compiler can do hardware __float128... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for PowerPC ISA 3.0 to build hardware __float128 libraries" >&5
+$as_echo_n "checking for PowerPC ISA 3.0 to build hardware __float128 libraries... " >&6; }
 if test "${libgcc_cv_powerpc_float128_hw+set}" = set; then :
   $as_echo_n "(cached) " >&6
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#pragma GCC target ("cpu=power9,float128,float128-hardware")
+#pragma GCC target ("vsx,power9-vector")
      #include <sys/auxv.h>
      #ifndef AT_PLATFORM
      #error "AT_PLATFORM is not defined"
      #endif
-     __float128 add (__float128 a, __float128 b)
+     vector unsigned char (vector unsigned char a, vector unsigned char b)
      {
-       __float128 ret;
+       vector unsigned char ret;
        __asm__ ("xsaddqp %0,%1,%2" : "=v" (ret) : "v" (a), "v" (b));
        return ret;
      }
diff --git a/libgcc/configure.ac b/libgcc/configure.ac
index 897259e..269997f 100644
--- a/libgcc/configure.ac
+++ b/libgcc/configure.ac
@@ -374,26 +374,30 @@ esac
 esac
 
 case ${host} in
+# At present, we cannot turn -mfloat128 on via #pragma GCC target,
+# so just check if we have VSX (ISA 2.06) support to build the
+# software libraries, and whether the assembler can handle xsaddqp
+# for hardware support.
 powerpc*-*-linux*)
-  AC_CACHE_CHECK([whether the PowerPC compiler can do __float128],
+  AC_CACHE_CHECK([for PowerPC ISA 2.06 to build __float128 libraries],
 		 [libgcc_cv_powerpc_float128],
 		 [AC_COMPILE_IFELSE(
-    [#pragma GCC target ("vsx,float128")
-     __float128 add (__float128 *a) { return *a + *(a+1); }],
+    [#pragma GCC target ("vsx")
+     vector double dadd (vector double a, vector double b) { return a + b; }],
     [libgcc_cv_powerpc_float128=yes],
     [libgcc_cv_powerpc_float128=no])])
 
-  AC_CACHE_CHECK([whether the PowerPC compiler can do hardware __float128],
+  AC_CACHE_CHECK([for PowerPC ISA 3.0 to build hardware __float128 libraries],
 		 [libgcc_cv_powerpc_float128_hw],
 		 [AC_COMPILE_IFELSE(
-    [#pragma GCC target ("cpu=power9,float128,float128-hardware")
+    [#pragma GCC target ("vsx,power9-vector")
      #include <sys/auxv.h>
      #ifndef AT_PLATFORM
      #error "AT_PLATFORM is not defined"
      #endif
-     __float128 add (__float128 a, __float128 b)
+     vector unsigned char (vector unsigned char a, vector unsigned char b)
      {
-       __float128 ret;
+       vector unsigned char ret;
        __asm__ ("xsaddqp %0,%1,%2" : "=v" (ret) : "v" (a), "v" (b));
        return ret;
      }