From: Michael Meissner <meissner@linux.vnet.ibm.com>
Date: Wed, 12 Jul 2017 23:07:50 +0000 (+0000)
Subject: re PR target/81193 (PowerPC GCC __builtin_cpu_is and __builtin_cpu_supports should... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=3787ee47fc5c67bffa0508e8a9cc70acb8ce4278;p=gcc.git

re PR target/81193 (PowerPC GCC __builtin_cpu_is and __builtin_cpu_supports should warn about old libraries)

[gcc]
2017-07-12  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/81193
	* config/rs6000/rs6000-c.c (rs6000_cpu_cpp_builtins): If GLIBC
	provides the hardware capability bits, define the macro
	__BUILTIN_CPU_SUPPORTS__.
	* config/rs6000/rs6000.c (cpu_expand_builtin): Generate a warning
	if GLIBC does not provide the hardware capability bits.  Add a
	gcc_unreachable call if the built-in cpu function is neither
	__builtin_cpu_is nor __builtin_cpu_supports.
	(rs6000_get_function_versions_dispatcher): Change the warning
	that an old GLIBC is used which does not export the capability
	bits to be an error.
	* doc/extend.texi (target_clones attribute): Document the
	restriction that GLIBC 2.23 or newer is needed on the PowerPC.
	(PowerPC built-in functions): Document that GLIBC 2.23 or newer is
	needed by __builtin_cpu_is and __builtin_cpu_supports.  Document
	the macros defined by GCC if the newer GLIBC is available.

[gcc/testsuite]
2017-07-12  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/81193
	* gcc.target/powerpc/bmi-andn-1.c: Add guard against using
	__builtin_cpu_supports with old GLIBC's.
	* gcc.target/powerpc/bmi-andn-2.c: Likewise.
	* gcc.target/powerpc/bmi-bextr-1.c: Likewise.
	* gcc.target/powerpc/bmi-bextr-2.c: Likewise.
	* gcc.target/powerpc/bmi-bextr-4.c: Likewise.
	* gcc.target/powerpc/bmi-bextr-5.c: Likewise.
	* gcc.target/powerpc/bmi-blsi-1.c: Likewise.
	* gcc.target/powerpc/bmi-blsi-2.c: Likewise.
	* gcc.target/powerpc/bmi-blsmsk-1.c: Likewise.
	* gcc.target/powerpc/bmi-blsmsk-2.c: Likewise.
	* gcc.target/powerpc/bmi-blsr-1.c: Likewise.
	* gcc.target/powerpc/bmi-blsr-2.c: Likewise.
	* gcc.target/powerpc/bmi-tzcnt-1.c: Likewise.
	* gcc.target/powerpc/bmi-tzcnt-2.c: Likewise.
	* gcc.target/powerpc/bmi2-bzhi32-1.c: Likewise.
	* gcc.target/powerpc/bmi2-bzhi64-1.c: Likewise.
	* gcc.target/powerpc/bmi2-mulx32-1.c: Likewise.
	* gcc.target/powerpc/bmi2-mulx32-2.c: Likewise.
	* gcc.target/powerpc/bmi2-mulx64-1.c: Likewise.
	* gcc.target/powerpc/bmi2-mulx64-2.c: Likewise.
	* gcc.target/powerpc/bmi2-pdep32-1.c: Likewise.
	* gcc.target/powerpc/bmi2-pdep64-1.c: Likewise.
	* gcc.target/powerpc/bmi2-pext32-1.c: Likewise.
	* gcc.target/powerpc/bmi2-pext64-1.c: Likewise.
	* gcc.target/powerpc/cpu-builtin-1.c: Likewise.

[libgcc]
2017-07-12  Michael Meissner  <meissner@linux.vnet.ibm.com>

	PR target/81193
	* configure.ac (PowerPC float128 hardware support): Test whether
	we can use __builtin_cpu_supports before enabling the ifunc
	handler.
	* configure: Regenerate.

From-SVN: r250165
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f9350a5183e..6e62befe6d1 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,22 @@
+2017-07-12  Michael Meissner  <meissner@linux.vnet.ibm.com>
+
+	PR target/81193
+	* config/rs6000/rs6000-c.c (rs6000_cpu_cpp_builtins): If GLIBC
+	provides the hardware capability bits, define the macro
+	__BUILTIN_CPU_SUPPORTS__.
+	* config/rs6000/rs6000.c (cpu_expand_builtin): Generate a warning
+	if GLIBC does not provide the hardware capability bits.  Add a
+	gcc_unreachable call if the built-in cpu function is neither
+	__builtin_cpu_is nor __builtin_cpu_supports.
+	(rs6000_get_function_versions_dispatcher): Change the warning
+	that an old GLIBC is used which does not export the capability
+	bits to be an error.
+	* doc/extend.texi (target_clones attribute): Document the
+	restriction that GLIBC 2.23 or newer is needed on the PowerPC.
+	(PowerPC built-in functions): Document that GLIBC 2.23 or newer is
+	needed by __builtin_cpu_is and __builtin_cpu_supports.  Document
+	the macros defined by GCC if the newer GLIBC is available.
+
 2017-07-12  Jeff Law  <law@redhat.com>
 
 	* config/riscv/riscv.c: Remove unnecessary includes.  Reorder
diff --git a/gcc/config/rs6000/rs6000-c.c b/gcc/config/rs6000/rs6000-c.c
index c7694425feb..96521a27093 100644
--- a/gcc/config/rs6000/rs6000-c.c
+++ b/gcc/config/rs6000/rs6000-c.c
@@ -644,6 +644,9 @@ rs6000_cpu_cpp_builtins (cpp_reader *pfile)
     builtin_define ("__FLOAT128_HARDWARE__");
   if (TARGET_LONG_DOUBLE_128 && FLOAT128_IBM_P (TFmode))
     builtin_define ("__ibm128=long double");
+#ifdef TARGET_LIBC_PROVIDES_HWCAP_IN_TCB
+  builtin_define ("__BUILTIN_CPU_SUPPORTS__");
+#endif
 
   /* We needed to create a keyword if -mfloat128-type was used but not -mfloat,
      so we used __ieee128.  If -mfloat128 was used, create a #define back to
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 10c552152a4..af5b5f1a2f6 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -15176,6 +15176,8 @@ cpu_expand_builtin (enum rs6000_builtins fcode, tree exp ATTRIBUTE_UNUSED,
       emit_insn (gen_eqsi3 (scratch2, scratch1, const0_rtx));
       emit_insn (gen_rtx_SET (target, gen_rtx_XOR (SImode, scratch2, const1_rtx)));
     }
+  else
+    gcc_unreachable ();
 
   /* Record that we have expanded a CPU builtin, so that we can later
      emit a reference to the special symbol exported by LIBC to ensure we
@@ -15183,6 +15185,9 @@ cpu_expand_builtin (enum rs6000_builtins fcode, tree exp ATTRIBUTE_UNUSED,
   cpu_builtin_p = true;
 
 #else
+  warning (0, "%s needs GLIBC (2.23 and newer) that exports hardware "
+	   "capability bits", rs6000_builtin_info[(size_t) fcode].name);
+  
   /* For old LIBCs, always return FALSE.  */
   emit_move_insn (target, GEN_INT (0));
 #endif /* TARGET_LIBC_PROVIDES_HWCAP_IN_TCB */
@@ -37284,10 +37289,10 @@ rs6000_get_function_versions_dispatcher (void *decl)
   default_node = default_version_info->this_node;
 
 #ifndef TARGET_LIBC_PROVIDES_HWCAP_IN_TCB
-  warning_at (DECL_SOURCE_LOCATION (default_node->decl), 0,
-	      "target_clone needs GLIBC (2.23 and newer) to export hardware "
-	      "capability bits");
-#endif
+  error_at (DECL_SOURCE_LOCATION (default_node->decl),
+	    "target_clones attribute needs GLIBC (2.23 and newer) that "
+	    "exports hardware capability bits");
+#else
 
   if (targetm.has_ifunc_p ())
     {
@@ -37320,6 +37325,7 @@ rs6000_get_function_versions_dispatcher (void *decl)
 		"multiversioning needs ifunc which is not supported "
 		"on this target");
     }
+#endif
 
   return dispatch_decl;
 }
diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 530a82dd2c0..27363fc5a92 100644
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -3282,7 +3282,8 @@ one compiled with @option{-msse4.1} and another with @option{-mavx}.
 On a PowerPC, you can compile a function with
 @code{target_clones("cpu=power9,default")}.  GCC will create two
 function clones, one compiled with @option{-mcpu=power9} and another
-with the default options.
+with the default options.  GCC must be configured to use GLIBC 2.23 or
+newer in order to use the @code{target_clones} attribute.
 
 It also creates a resolver function (see
 the @code{ifunc} attribute above) that dynamically selects a clone
@@ -14945,8 +14946,18 @@ to maintain API compatibility with the x86 builtins.
 
 @deftypefn {Built-in Function} int __builtin_cpu_is (const char *@var{cpuname})
 This function returns a value of @code{1} if the run-time CPU is of type
-@var{cpuname} and returns @code{0} otherwise. The following CPU names can be
-detected:
+@var{cpuname} and returns @code{0} otherwise
+
+The @code{__builtin_cpu_is} function requires GLIBC 2.23 or newer
+which exports the hardware capability bits.  GCC defines the macro
+@code{__BUILTIN_CPU_SUPPORTS__} if the @code{__builtin_cpu_supports}
+built-in function is fully supported.
+
+If GCC was configured to use a GLIBC before 2.23, the built-in
+function @code{__builtin_cpu_is} always returns a 0 and the compiler
+issues a warning.
+
+The following CPU names can be detected:
 
 @table @samp
 @item power9
@@ -14983,20 +14994,33 @@ IBM PowerPC Cell Broadband Engine Architecture CPU.
 
 Here is an example:
 @smallexample
-if (__builtin_cpu_is ("power8"))
-  @{
-     do_power8 (); // POWER8 specific implementation.
-  @}
-else
-  @{
-     do_generic (); // Generic implementation.
-  @}
+#ifdef __BUILTIN_CPU_SUPPORTS__
+  if (__builtin_cpu_is ("power8"))
+    @{
+       do_power8 (); // POWER8 specific implementation.
+    @}
+  else
+#endif
+    @{
+       do_generic (); // Generic implementation.
+    @}
 @end smallexample
 @end deftypefn
 
 @deftypefn {Built-in Function} int __builtin_cpu_supports (const char *@var{feature})
 This function returns a value of @code{1} if the run-time CPU supports the HWCAP
-feature @var{feature} and returns @code{0} otherwise. The following features can be
+feature @var{feature} and returns @code{0} otherwise.
+
+The @code{__builtin_cpu_supports} function requires GLIBC 2.23 or
+newer which exports the hardware capability bits.  GCC defines the
+macro @code{__BUILTIN_CPU_SUPPORTS__} if the
+@code{__builtin_cpu_supports} built-in function is fully supported.
+
+If GCC was configured to use a GLIBC before 2.23, the built-in
+function @code{__builtin_cpu_suports} always returns a 0 and the
+compiler issues a warning.
+
+The following features can be
 detected:
 
 @table @samp
@@ -15080,14 +15104,16 @@ CPU supports the vector-scalar extension.
 
 Here is an example:
 @smallexample
-if (__builtin_cpu_supports ("fpu"))
-  @{
-     asm("fadd %0,%1,%2" : "=d"(dst) : "d"(src1), "d"(src2));
-  @}
-else
-  @{
-     dst = __fadd (src1, src2); // Software FP addition function.
-  @}
+#ifdef __BUILTIN_CPU_SUPPORTS__
+  if (__builtin_cpu_supports ("fpu"))
+    @{
+       asm("fadd %0,%1,%2" : "=d"(dst) : "d"(src1), "d"(src2));
+    @}
+  else
+#endif
+    @{
+       dst = __fadd (src1, src2); // Software FP addition function.
+    @}
 @end smallexample
 @end deftypefn
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2afa99c044f..b3b4f75f4ef 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,33 @@
+2017-07-12  Michael Meissner  <meissner@linux.vnet.ibm.com>
+
+	PR target/81193
+	* gcc.target/powerpc/bmi-andn-1.c: Add guard against using
+	__builtin_cpu_supports with old GLIBC's.
+	* gcc.target/powerpc/bmi-andn-2.c: Likewise.
+	* gcc.target/powerpc/bmi-bextr-1.c: Likewise.
+	* gcc.target/powerpc/bmi-bextr-2.c: Likewise.
+	* gcc.target/powerpc/bmi-bextr-4.c: Likewise.
+	* gcc.target/powerpc/bmi-bextr-5.c: Likewise.
+	* gcc.target/powerpc/bmi-blsi-1.c: Likewise.
+	* gcc.target/powerpc/bmi-blsi-2.c: Likewise.
+	* gcc.target/powerpc/bmi-blsmsk-1.c: Likewise.
+	* gcc.target/powerpc/bmi-blsmsk-2.c: Likewise.
+	* gcc.target/powerpc/bmi-blsr-1.c: Likewise.
+	* gcc.target/powerpc/bmi-blsr-2.c: Likewise.
+	* gcc.target/powerpc/bmi-tzcnt-1.c: Likewise.
+	* gcc.target/powerpc/bmi-tzcnt-2.c: Likewise.
+	* gcc.target/powerpc/bmi2-bzhi32-1.c: Likewise.
+	* gcc.target/powerpc/bmi2-bzhi64-1.c: Likewise.
+	* gcc.target/powerpc/bmi2-mulx32-1.c: Likewise.
+	* gcc.target/powerpc/bmi2-mulx32-2.c: Likewise.
+	* gcc.target/powerpc/bmi2-mulx64-1.c: Likewise.
+	* gcc.target/powerpc/bmi2-mulx64-2.c: Likewise.
+	* gcc.target/powerpc/bmi2-pdep32-1.c: Likewise.
+	* gcc.target/powerpc/bmi2-pdep64-1.c: Likewise.
+	* gcc.target/powerpc/bmi2-pext32-1.c: Likewise.
+	* gcc.target/powerpc/bmi2-pext64-1.c: Likewise.
+	* gcc.target/powerpc/cpu-builtin-1.c: Likewise.
+
 2017-07-12  Carl Love  <cel@us.ibm.com>
 
 	* gcc.target/powerpc/p9-xxbr-1.c (rev_bool_char, rev_bool_short,
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-andn-1.c b/gcc/testsuite/gcc.target/powerpc/bmi-andn-1.c
index 8d8d643e088..3702bdd77fe 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-andn-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-andn-1.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-andn-2.c b/gcc/testsuite/gcc.target/powerpc/bmi-andn-2.c
index a4260b51b79..a6f5d5084c9 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-andn-2.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-andn-2.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-bextr-1.c b/gcc/testsuite/gcc.target/powerpc/bmi-bextr-1.c
index f532c6a3bb5..45e5bdd8510 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-bextr-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-bextr-1.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O2 -fno-inline" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-bextr-2.c b/gcc/testsuite/gcc.target/powerpc/bmi-bextr-2.c
index b3515259fca..52f78df1267 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-bextr-2.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-bextr-2.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3 -fno-inline" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-bextr-4.c b/gcc/testsuite/gcc.target/powerpc/bmi-bextr-4.c
index 8701d9fbd1d..3ca56665033 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-bextr-4.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-bextr-4.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3 -fno-inline" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-bextr-5.c b/gcc/testsuite/gcc.target/powerpc/bmi-bextr-5.c
index 2835adedced..e43e2da422a 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-bextr-5.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-bextr-5.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3 -fno-inline" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-blsi-1.c b/gcc/testsuite/gcc.target/powerpc/bmi-blsi-1.c
index 418d336b43e..345a7eb9def 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-blsi-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-blsi-1.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3 -fno-inline" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-blsi-2.c b/gcc/testsuite/gcc.target/powerpc/bmi-blsi-2.c
index 1d51b5a75bb..f2e1a58f5ed 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-blsi-2.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-blsi-2.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3 -fno-inline" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-blsmsk-1.c b/gcc/testsuite/gcc.target/powerpc/bmi-blsmsk-1.c
index df34d53ab86..481b09f77ce 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-blsmsk-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-blsmsk-1.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3 -fno-inline" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-blsmsk-2.c b/gcc/testsuite/gcc.target/powerpc/bmi-blsmsk-2.c
index e5fe12d4ee0..3ba7e97dd47 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-blsmsk-2.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-blsmsk-2.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3 -fno-inline" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-blsr-1.c b/gcc/testsuite/gcc.target/powerpc/bmi-blsr-1.c
index 645e00f05ee..c383b7914e2 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-blsr-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-blsr-1.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3 -fno-inline" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-blsr-2.c b/gcc/testsuite/gcc.target/powerpc/bmi-blsr-2.c
index f290b838001..61d962b9150 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-blsr-2.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-blsr-2.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3 -fno-inline" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-tzcnt-1.c b/gcc/testsuite/gcc.target/powerpc/bmi-tzcnt-1.c
index 25b096ad0bc..25ba3dc238e 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-tzcnt-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-tzcnt-1.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3 -fno-inline" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi-tzcnt-2.c b/gcc/testsuite/gcc.target/powerpc/bmi-tzcnt-2.c
index 75397e53eb6..1b80ccbdaa9 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi-tzcnt-2.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi-tzcnt-2.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3 -fno-inline" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi2-bzhi32-1.c b/gcc/testsuite/gcc.target/powerpc/bmi2-bzhi32-1.c
index b2a6d4d74ea..f0943d7f974 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi2-bzhi32-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi2-bzhi32-1.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi2-bzhi64-1.c b/gcc/testsuite/gcc.target/powerpc/bmi2-bzhi64-1.c
index a09d5d24b51..33f1748b44e 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi2-bzhi64-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi2-bzhi64-1.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi2-mulx32-1.c b/gcc/testsuite/gcc.target/powerpc/bmi2-mulx32-1.c
index eda74690589..870679c779f 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi2-mulx32-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi2-mulx32-1.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include "bmi2-check.h"
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi2-mulx32-2.c b/gcc/testsuite/gcc.target/powerpc/bmi2-mulx32-2.c
index a6fc38cbf55..b8327741c3a 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi2-mulx32-2.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi2-mulx32-2.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi2-mulx64-1.c b/gcc/testsuite/gcc.target/powerpc/bmi2-mulx64-1.c
index 5334de20fc5..b1e4a13c2af 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi2-mulx64-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi2-mulx64-1.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include "bmi2-check.h"
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi2-mulx64-2.c b/gcc/testsuite/gcc.target/powerpc/bmi2-mulx64-2.c
index ff119262c64..d57f05503c5 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi2-mulx64-2.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi2-mulx64-2.c
@@ -1,6 +1,7 @@
 /* { dg-do run } */
 /* { dg-options "-O3" } */
 /* { dg-require-effective-target lp64 } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi2-pdep32-1.c b/gcc/testsuite/gcc.target/powerpc/bmi2-pdep32-1.c
index 12cf92eec2c..a07567389d0 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi2-pdep32-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi2-pdep32-1.c
@@ -3,6 +3,7 @@
 /* { dg-require-effective-target lp64 } */
 /* { dg-require-effective-target vsx_hw } */
 /* { dg-skip-if "do not override -mcpu" { powerpc*-*-* } { "-mcpu=*" } { "-mcpu=power7" } } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi2-pdep64-1.c b/gcc/testsuite/gcc.target/powerpc/bmi2-pdep64-1.c
index 01e1fdaf538..1268239e61f 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi2-pdep64-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi2-pdep64-1.c
@@ -3,6 +3,7 @@
 /* { dg-require-effective-target lp64 } */
 /* { dg-require-effective-target vsx_hw } */
 /* { dg-skip-if "do not override -mcpu" { powerpc*-*-* } { "-mcpu=*" } { "-mcpu=power7" } } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi2-pext32-1.c b/gcc/testsuite/gcc.target/powerpc/bmi2-pext32-1.c
index 9450ef56aed..762ed1b0325 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi2-pext32-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi2-pext32-1.c
@@ -3,6 +3,7 @@
 /* { dg-require-effective-target lp64 } */
 /* { dg-require-effective-target vsx_hw } */
 /* { dg-skip-if "do not override -mcpu" { powerpc*-*-* } { "-mcpu=*" } { "-mcpu=power7" } } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/bmi2-pext64-1.c b/gcc/testsuite/gcc.target/powerpc/bmi2-pext64-1.c
index b76ae81b5bc..5e269ec47de 100644
--- a/gcc/testsuite/gcc.target/powerpc/bmi2-pext64-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/bmi2-pext64-1.c
@@ -3,6 +3,7 @@
 /* { dg-require-effective-target lp64 } */
 /* { dg-require-effective-target vsx_hw } */
 /* { dg-skip-if "do not override -mcpu" { powerpc*-*-* } { "-mcpu=*" } { "-mcpu=power7" } } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 #define NO_WARN_X86_INTRINSICS 1
 #include <x86intrin.h>
diff --git a/gcc/testsuite/gcc.target/powerpc/cpu-builtin-1.c b/gcc/testsuite/gcc.target/powerpc/cpu-builtin-1.c
index 684c0f6d17d..c13fed7efd4 100644
--- a/gcc/testsuite/gcc.target/powerpc/cpu-builtin-1.c
+++ b/gcc/testsuite/gcc.target/powerpc/cpu-builtin-1.c
@@ -1,5 +1,6 @@
 /* { dg-do compile { target { powerpc*-*-* } } } */
 /* { dg-skip-if "" { powerpc*-*-darwin* } } */
+/* { dg-require-effective-target ppc_cpu_supports_hw } */
 
 void
 use_cpu_is_builtins (unsigned int *p)
diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index 1a4de2c31e6..36e08471afb 100644
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,11 @@
+2017-07-12  Michael Meissner  <meissner@linux.vnet.ibm.com>
+
+	PR target/81193
+	* configure.ac (PowerPC float128 hardware support): Test whether
+	we can use __builtin_cpu_supports before enabling the ifunc
+	handler.
+	* configure: Regenerate.
+
 2017-07-10  Vineet Gupta <vgupta@synopsys.com>
 
 	* config.host: Remove uclibc from arc target spec.
diff --git a/libgcc/configure b/libgcc/configure
index 42dda7fbeec..15d34b27cc0 100644
--- a/libgcc/configure
+++ b/libgcc/configure
@@ -4975,10 +4975,10 @@ esac
 esac
 
 case ${host} in
-# At present, we cannot turn -mfloat128 on via #pragma GCC target,
-# so just check if we have VSX (ISA 2.06) support to build the
-# software libraries, and whether the assembler can handle xsaddqp
-# for hardware support.
+# At present, we cannot turn -mfloat128 on via #pragma GCC target, so just
+# check if we have VSX (ISA 2.06) support to build the software libraries, and
+# whether the assembler can handle xsaddqp for hardware support.  Also check if
+# a new glibc is being used so that __builtin_cpu_supports can be used.
 powerpc*-*-linux*)
   saved_CFLAGS="$CFLAGS"
   CFLAGS="$CFLAGS -mabi=altivec -mvsx -mfloat128"
@@ -5013,6 +5013,9 @@ else
      #ifndef AT_PLATFORM
      #error "AT_PLATFORM is not defined"
      #endif
+     #ifndef __BUILTIN_CPU_SUPPORTS__
+     #error "__builtin_cpu_supports is not available"
+     #endif
      vector unsigned char add (vector unsigned char a, vector unsigned char b)
      {
        vector unsigned char ret;
diff --git a/libgcc/configure.ac b/libgcc/configure.ac
index 6bcaad651ff..da499716f8c 100644
--- a/libgcc/configure.ac
+++ b/libgcc/configure.ac
@@ -376,10 +376,10 @@ esac
 esac
 
 case ${host} in
-# At present, we cannot turn -mfloat128 on via #pragma GCC target,
-# so just check if we have VSX (ISA 2.06) support to build the
-# software libraries, and whether the assembler can handle xsaddqp
-# for hardware support.
+# At present, we cannot turn -mfloat128 on via #pragma GCC target, so just
+# check if we have VSX (ISA 2.06) support to build the software libraries, and
+# whether the assembler can handle xsaddqp for hardware support.  Also check if
+# a new glibc is being used so that __builtin_cpu_supports can be used.
 powerpc*-*-linux*)
   saved_CFLAGS="$CFLAGS"
   CFLAGS="$CFLAGS -mabi=altivec -mvsx -mfloat128"
@@ -398,6 +398,9 @@ powerpc*-*-linux*)
      #ifndef AT_PLATFORM
      #error "AT_PLATFORM is not defined"
      #endif
+     #ifndef __BUILTIN_CPU_SUPPORTS__
+     #error "__builtin_cpu_supports is not available"
+     #endif
      vector unsigned char add (vector unsigned char a, vector unsigned char b)
      {
        vector unsigned char ret;