mmix.h (FUNCTION_INCOMING_ARG_REGNO_P): Don't define bogus target macro.

	* config/mmix/mmix.h (FUNCTION_INCOMING_ARG_REGNO_P): Don't define
	bogus target macro.
	(INCOMING_REGNO, OUTGOING_REGNO): Define.
	* config/mmix/mmix.c (mmix_opposite_regno): New function.
	* config/mmix/mmix-protos.h (mmix_opposite_regno): Prototype.

From-SVN: r128744

3 files changed, 24 insertions, 10 deletions

diff --git a/gcc/config/mmix/mmix-protos.h b/gcc/config/mmix/mmix-protos.h
index c963147..d71064a 100644
--- a/gcc/config/mmix/mmix-protos.h
+++ b/gcc/config/mmix/mmix-protos.h
@@ -49,6 +49,7 @@ extern void mmix_asm_output_align (FILE *, int);
 extern int mmix_shiftable_wyde_value (unsigned HOST_WIDEST_INT);
 extern void mmix_output_register_setting (FILE *, int, HOST_WIDEST_INT, int);
 extern void mmix_conditional_register_usage (void);
+extern int mmix_opposite_regno (int, int);
 extern int mmix_local_regno (int);
 extern int mmix_dbx_register_number (int);
 extern int mmix_use_simple_return (void);
diff --git a/gcc/config/mmix/mmix.c b/gcc/config/mmix/mmix.c
index 699a30d..a55b0dc 100644
--- a/gcc/config/mmix/mmix.c
+++ b/gcc/config/mmix/mmix.c
@@ -319,6 +319,26 @@ mmix_conditional_register_usage (void)
 	reg_names[i]++;
 }
 
+/* INCOMING_REGNO and OUTGOING_REGNO worker function.
+   Those two macros must only be applied to function argument
+   registers.  FIXME: for their current use in gcc, it'd be better
+   with an explicit specific additional FUNCTION_INCOMING_ARG_REGNO_P
+   a'la FUNCTION_ARG / FUNCTION_INCOMING_ARG instead of forcing the
+   target to commit to a fixed mapping and for any unspecified
+   register use.  */
+
+int
+mmix_opposite_regno (int regno, int incoming)
+{
+  if (!mmix_function_arg_regno_p (regno, incoming))
+    return regno;
+
+  return
+    regno - (incoming
+	     ? MMIX_FIRST_INCOMING_ARG_REGNUM - MMIX_FIRST_ARG_REGNUM
+	     : MMIX_FIRST_ARG_REGNUM - MMIX_FIRST_INCOMING_ARG_REGNUM);
+}
+
 /* LOCAL_REGNO.
    All registers that are part of the register stack and that will be
    saved are local.  */
diff --git a/gcc/config/mmix/mmix.h b/gcc/config/mmix/mmix.h
index 8f09cdb..19aab6f 100644
--- a/gcc/config/mmix/mmix.h
+++ b/gcc/config/mmix/mmix.h
@@ -319,13 +319,9 @@ extern int target_flags;
 
 #define CONDITIONAL_REGISTER_USAGE mmix_conditional_register_usage ()
 
-/* No INCOMING_REGNO or OUTGOING_REGNO, since those macros are not usable
-   for MMIX: it doesn't have a fixed register window size.  FIXME: Perhaps
-   we should say something about $0..$15 may sometimes be the incoming
-   $16..$31.  Those macros need better documentation; it looks like
-   they're just bogus and that FUNCTION_INCOMING_ARG_REGNO_P and
-   FUNCTION_OUTGOING_VALUE should be used where they're used.  For the
-   moment, do nothing; things seem to work anyway.  */
+#define INCOMING_REGNO(OUT) mmix_opposite_regno (OUT, 0)
+
+#define OUTGOING_REGNO(IN) mmix_opposite_regno (IN, 1)
 
 /* Defining LOCAL_REGNO is necessary in presence of prologue/epilogue,
    else GCC will be confused that those registers aren't saved and
@@ -644,9 +640,6 @@ typedef struct { int regs; int lib; } CUMULATIVE_ARGS;
 #define FUNCTION_ARG_REGNO_P(REGNO)		\
  mmix_function_arg_regno_p (REGNO, 0)
 
-#define FUNCTION_INCOMING_ARG_REGNO_P(REGNO)		\
- mmix_function_arg_regno_p (REGNO, 1)
-
 
 /* Node: Register Arguments */