rx.c (rx_can_use_simple_return): New function.

        * config/rx/rx.c (rx_can_use_simple_return): New function.
        * config/rx/rx-protos.h (rx_can_use_simple_return): Prototype.
        * config/rx/rx.md (return): Predicate on rx_can_use_simple_return.

From-SVN: r183252

4 files changed, 40 insertions, 6 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 055cc2e..ceba9c2 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2012-01-17  Nick Clifton  <nickc@redhat.com>
+
+	* config/rx/rx.c (rx_can_use_simple_return): New function.
+	* config/rx/rx-protos.h (rx_can_use_simple_return): Prototype.
+	* config/rx/rx.md (return): Predicate on rx_can_use_simple_return.
+
 2012-01-17  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/51782
diff --git a/gcc/config/rx/rx-protos.h b/gcc/config/rx/rx-protos.h
index 365bf66..f0352a8 100644
--- a/gcc/config/rx/rx-protos.h
+++ b/gcc/config/rx/rx-protos.h
@@ -1,5 +1,6 @@
 /* Exported function prototypes from the Renesas RX backend.
-   Copyright (C) 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2009, 2010, 2011, 2012
+   Free Software Foundation, Inc.
    Contributed by Red Hat.
 
    This file is part of GCC.
@@ -21,6 +22,8 @@
 #ifndef GCC_RX_PROTOS_H
 #define GCC_RX_PROTOS_H
 
+extern bool             rx_can_use_simple_return (void);
+extern void		rx_expand_epilogue (bool);
 extern void		rx_expand_prologue (void);
 extern int		rx_initial_elimination_offset (int, int);
 
@@ -29,7 +32,6 @@ extern int		rx_adjust_insn_length (rtx, int);
 extern int 		rx_align_for_label (rtx, int);
 extern void             rx_emit_stack_popm (rtx *, bool);
 extern void             rx_emit_stack_pushm (rtx *);
-extern void		rx_expand_epilogue (bool);
 extern char *		rx_gen_move_template (rtx *, bool);
 extern bool		rx_is_legitimate_constant (enum machine_mode, rtx);
 extern bool		rx_is_restricted_memory_address (rtx,
diff --git a/gcc/config/rx/rx.c b/gcc/config/rx/rx.c
index 4a73285..655f318 100644
--- a/gcc/config/rx/rx.c
+++ b/gcc/config/rx/rx.c
@@ -1,5 +1,6 @@
 /* Subroutines used for code generation on Renesas RX processors.
-   Copyright (C) 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+   Copyright (C) 2008, 2009, 2010, 2011, 2012
+   Free Software Foundation, Inc.
    Contributed by Red Hat.
 
    This file is part of GCC.
@@ -1818,7 +1819,31 @@ gen_rx_popm_vector (unsigned int low, unsigned int high)
 
   return vector;
 }
-  
+
+/* Returns true if a simple return insn can be used.  */
+
+bool
+rx_can_use_simple_return (void)
+{
+  unsigned int low;
+  unsigned int high;
+  unsigned int frame_size;
+  unsigned int stack_size;
+  unsigned int register_mask;
+
+  if (is_naked_func (NULL_TREE)
+      || is_fast_interrupt_func (NULL_TREE)
+      || is_interrupt_func (NULL_TREE))
+    return false;
+
+  rx_get_stack_layout (& low, & high, & register_mask,
+		       & frame_size, & stack_size);
+
+  return (register_mask == 0
+	  && (frame_size + stack_size) == 0
+	  && low == 0);
+}
+
 void
 rx_expand_epilogue (bool is_sibcall)
 {
diff --git a/gcc/config/rx/rx.md b/gcc/config/rx/rx.md
index 92768c6..1ba603f 100644
--- a/gcc/config/rx/rx.md
+++ b/gcc/config/rx/rx.md
@@ -1,5 +1,6 @@
 ;;  Machine Description for Renesas RX processors
-;;  Copyright (C) 2008, 2009, 2010, 2011 Free Software Foundation, Inc.
+;;  Copyright (C) 2008, 2009, 2010, 2011, 2012
+;;  Free Software Foundation, Inc.
 ;;  Contributed by Red Hat.
 
 ;; This file is part of GCC.
@@ -342,7 +343,7 @@
 
 (define_expand "return"
   [(return)]
-  ""
+  "rx_can_use_simple_return ()"
   "rx_expand_epilogue (false); DONE;"
 )