[Patch AArch64] Use software sqrt expansion always for -mlow-precision-recip-sqrt

gcc/

	* config/aarch64/aarch64.c (use_rsqrt_p): Always use software
	reciprocal sqrt for -mlow-precision-recip-sqrt.

From-SVN: r233462

gcc/ChangeLog

 2016-02-16  James Greenhalgh  <james.greenhalgh@arm.com>
+
+	* config/aarch64/aarch64.c (use_rsqrt_p): Always use software
+	reciprocal sqrt for -mlow-precision-recip-sqrt.
+
+2016-02-16  James Greenhalgh  <james.greenhalgh@arm.com>
 	    Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>
 
 	* config/aarch64/aarch64.c (aarch64_expand_vector_init): Refactor,

gcc/config/aarch64/aarch64.c

@@ -7468,8 +7468,9 @@ use_rsqrt_p (void)
 {
   return (!flag_trapping_math
 	  && flag_unsafe_math_optimizations
-	  && (aarch64_tune_params.extra_tuning_flags
-	      & AARCH64_EXTRA_TUNE_RECIP_SQRT));
+	  && ((aarch64_tune_params.extra_tuning_flags
+	       & AARCH64_EXTRA_TUNE_RECIP_SQRT)
+	      || flag_mrecip_low_precision_sqrt));
 }
 
 /* Function to decide when to use