[PR91749][arm] FDPIC: Handle -mflip-thumb

2019-09-16  Christophe Lyon  <christophe.lyon@linaro.org>

	PR target/91749
	* config/arm/arm.c (arm_valid_target_attribute_rec): Make sure the
	mode attributed is supported by FDPIC.

From-SVN: r275799

gcc/ChangeLog

+2019-09-17  Christophe Lyon  <christophe.lyon@linaro.org>
+
+	PR target/91749
+	* config/arm/arm.c (arm_valid_target_attribute_rec): Make sure the
+	mode attributed is supported by FDPIC.
+
 2019-09-17  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/91790

gcc/config/arm/arm.c

@@ -31179,7 +31179,11 @@ arm_valid_target_attribute_rec (tree args, struct gcc_options *opts)
     {
       argstr = NULL;
       if (!strcmp (q, "thumb"))
-	opts->x_target_flags |= MASK_THUMB;
+	{
+	  opts->x_target_flags |= MASK_THUMB;
+	  if (TARGET_FDPIC && !arm_arch_thumb2)
+	    sorry ("FDPIC mode is not supported in Thumb-1 mode");
+	}
 
       else if (!strcmp (q, "arm"))
 	opts->x_target_flags &= ~MASK_THUMB;