re PR target/61570 (-march=native CPU you selected does not support x86-64 instruction under QEMU)

	PR target/61570
	* config/i386/driver-i386.c (host_detect_local_cpu): For unknown
	model family 6 CPU with has_longmode never use a CPU without
	64-bit support.

From-SVN: r211945

gcc/ChangeLog

+2014-06-24  Jakub Jelinek  <jakub@redhat.com>
+
+	PR target/61570
+	* config/i386/driver-i386.c (host_detect_local_cpu): For unknown
+	model family 6 CPU with has_longmode never use a CPU without
+	64-bit support.
+
 2014-06-24  H.J. Lu  <hongjiu.lu@intel.com>
 
 	PR target/61570

gcc/config/i386/driver-i386.c

@@ -745,6 +745,11 @@ const char *host_detect_local_cpu (int argc, const char **argv)
 		    /* Assume Core 2.  */
 		    cpu = "core2";
 		}
+	      else if (has_longmode)
+		/* Perhaps some emulator?  Assume x86-64, otherwise gcc
+		   -march=native would be unusable for 64-bit compilations,
+		   as all the CPUs below are 32-bit only.  */
+		cpu = "x86-64";
 	      else if (has_sse3)
 		/* It is Core Duo.  */
 		cpu = "pentium-m";