[NDS32] Fix wrong data flow when building nds32 target with --enable-checking=yes.

gcc/
	* config/nds32/constants.md (UNSPEC_VOLATILE_POP25_RETURN): New.
	* config/nds32/nds32.md (pop25return): New.
	* config/nds32/nds32.c (nds32_expand_epilogue_v3pop): Emit
	pop25return pattern.

From-SVN: r219710

gcc/ChangeLog

 2015-01-16  Chung-Ju Wu  <jasonwucj@gmail.com>
 
+	* config/nds32/constants.md (UNSPEC_VOLATILE_POP25_RETURN): New.
+	* config/nds32/nds32.md (pop25return): New.
+	* config/nds32/nds32.c (nds32_expand_epilogue_v3pop): Emit
+	pop25return pattern.
+
+2015-01-16  Chung-Ju Wu  <jasonwucj@gmail.com>
+
 	* doc/invoke.texi (NDS32 Options): Remove -mforce-fp-as-gp,
 	-mforbid-fp-as-gp, and -mex9 options.
 

gcc/config/nds32/constants.md

@@ -41,6 +41,7 @@
   UNSPEC_VOLATILE_MTUSR
   UNSPEC_VOLATILE_SETGIE_EN
   UNSPEC_VOLATILE_SETGIE_DIS
+  UNSPEC_VOLATILE_POP25_RETURN
 ])
 
 ;; ------------------------------------------------------------------------

gcc/config/nds32/nds32.c

@@ -3449,6 +3449,9 @@ nds32_expand_epilogue_v3pop (void)
       nds32_emit_stack_v3pop (Rb, Re,
 			      GEN_INT (14), GEN_INT (0));
     }
+
+  /* Generate return instruction.  */
+  emit_jump_insn (gen_pop25return ());
 }
 
 /* ------------------------------------------------------------------------ */

gcc/config/nds32/nds32.md

@@ -2253,3 +2253,15 @@ create_template:
    (set_attr "length" "4")])
 
 ;; ----------------------------------------------------------------------------
+
+;; Pseudo NOPs
+
+(define_insn "pop25return"
+  [(return)
+   (unspec_volatile:SI [(reg:SI LP_REGNUM)] UNSPEC_VOLATILE_POP25_RETURN)]
+  ""
+  "! return for pop 25"
+  [(set_attr "length" "0")]
+)
+
+;; ----------------------------------------------------------------------------