i386.h (TARGET_PREFER_AVX256): Also enable when TARGET_PREFER_AVX128 is set.

	* config/i386/i386.h (TARGET_PREFER_AVX256): Also
	enable when TARGET_PREFER_AVX128 is set.

From-SVN: r255105

gcc/ChangeLog

+2017-11-23  Sergey Shalnov  <Sergey.Shalnov@intel.com>
+
+	* config/i386/i386.h (TARGET_PREFER_AVX256): Also
+	enable when TARGET_PREFER_AVX128 is set.
+
 2017-11-23  Jan Hubicka  <hubicka@ucw.cz>
 
 	* ipa-profile.c (ipa_propagate_frequency_1): Use count instead of

gcc/config/i386/i386.h

@@ -2683,7 +2683,8 @@ extern void debug_dispatch_window (int);
 /* Use 128-bit AVX instructions in the auto-vectorizer.  */
 #define TARGET_PREFER_AVX128	(prefer_vector_width_type == PVW_AVX128)
 /* Use 256-bit AVX instructions in the auto-vectorizer.  */
-#define TARGET_PREFER_AVX256	(prefer_vector_width_type == PVW_AVX256)
+#define TARGET_PREFER_AVX256	(TARGET_PREFER_AVX128 \
+				 || prefer_vector_width_type == PVW_AVX256)
 
 #define IX86_HLE_ACQUIRE (1 << 16)
 #define IX86_HLE_RELEASE (1 << 17)