Add and use effective target rdrand

2017-05-01  Tom de Vries  <tom@codesourcery.com>

	PR testsuite/65941
	* lib/target-supports.exp (check_effective_target_rdrand): New proc.
	* g++.dg/other/pr59492.C: Require effective target rdrand.

From-SVN: r247438

gcc/testsuite/ChangeLog

+2017-05-01  Tom de Vries  <tom@codesourcery.com>
+
+	PR testsuite/65941
+	* lib/target-supports.exp (check_effective_target_rdrand): New proc.
+	* g++.dg/other/pr59492.C: Require effective target rdrand.
+
 2017-04-29  Volker Reichelt  <v.reichelt@netcologne.de>
 
 	* g++.dg/diagnostic/member-decl-1.C: New test.

gcc/testsuite/g++.dg/other/pr59492.C

@@ -2,6 +2,7 @@
 // { dg-options "-mx32 -fPIC" }
 // { dg-require-ifunc "" }
 // { dg-require-effective-target maybe_x32 }
+// { dg-require-effective-target rdrand }
 
 void
 __throw_runtime_error(const char*) __attribute__((__noreturn__));

gcc/testsuite/lib/target-supports.exp

@@ -8296,6 +8296,20 @@ proc check_effective_target_store_merge { } {
     return 0
 }
 
+# Return 1 if we're able to assemble rdrand
+
+proc check_effective_target_rdrand { } {
+    return [check_no_compiler_messages_nocache rdrand object {
+	unsigned int
+	__foo(void)
+	{
+	    unsigned int val;
+	    __builtin_ia32_rdrand32_step(&val);
+	    return val;
+	}
+    } "-mrdrnd" ]
+}
+
 # Return 1 if the target supports coprocessor instructions: cdp, ldc, stc, mcr and
 # mrc.
 proc check_effective_target_arm_coproc1_ok_nocache { } {