* config/mn10300/mn10300.c (TARGET_DEFAULT_TARGET_FLAGS): Add

MASK_PTR_A0D0.
(mn10300_return_in_memory): Support variable size types also.
(mn10300_pass_by_reference): Likewise.
(mn10300_function_value): New.
* config/mn10300/mn10300.h (FUNCTION_VALUE): Call the above.
(FUNCTION_OUTGOING_VALUE): Likewise.
* config/mn10300/mn10300.opt: Add -mreturn-pointer-on-d0.
* doc/invoke.texi: Document it.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@104508 138bc75d-0d04-0410-961f-82ee72b054a4

4 files changed, 44 insertions, 5 deletions

diff --git a/gcc/config/mn10300/mn10300-protos.h b/gcc/config/mn10300/mn10300-protos.h
index 0810dad6860..b094c853b4d 100644
--- a/gcc/config/mn10300/mn10300-protos.h
+++ b/gcc/config/mn10300/mn10300-protos.h
@@ -49,6 +49,7 @@ extern bool mn10300_wide_const_load_uses_clr (rtx operands[2]);
 #ifdef TREE_CODE
 extern struct rtx_def *function_arg (CUMULATIVE_ARGS *,
 				     enum machine_mode, tree, int);
+extern rtx mn10300_function_value (tree, tree, int);
 #endif /* TREE_CODE */
 
 extern void expand_prologue (void);
diff --git a/gcc/config/mn10300/mn10300.c b/gcc/config/mn10300/mn10300.c
index 789a38370b9..cf0fc9fc146 100644
--- a/gcc/config/mn10300/mn10300.c
+++ b/gcc/config/mn10300/mn10300.c
@@ -95,7 +95,7 @@ static int mn10300_arg_partial_bytes (CUMULATIVE_ARGS *, enum machine_mode,
 #define TARGET_ASM_FILE_START_FILE_DIRECTIVE true
 
 #undef TARGET_DEFAULT_TARGET_FLAGS
-#define TARGET_DEFAULT_TARGET_FLAGS MASK_MULT_BUG
+#define TARGET_DEFAULT_TARGET_FLAGS MASK_MULT_BUG | MASK_PTR_A0D0
 #undef TARGET_HANDLE_OPTION
 #define TARGET_HANDLE_OPTION mn10300_handle_option
 
@@ -1449,7 +1449,9 @@ static bool
 mn10300_return_in_memory (tree type, tree fntype ATTRIBUTE_UNUSED)
 {
   /* Return values > 8 bytes in length in memory.  */
-  return int_size_in_bytes (type) > 8 || TYPE_MODE (type) == BLKmode;
+  return (int_size_in_bytes (type) > 8
+	  || int_size_in_bytes (type) == 0
+	  || TYPE_MODE (type) == BLKmode);
 }
 
 /* Flush the argument registers to the stack for a stdarg function;
@@ -1505,7 +1507,7 @@ mn10300_pass_by_reference (CUMULATIVE_ARGS *cum ATTRIBUTE_UNUSED,
   else
     size = GET_MODE_SIZE (mode);
 
-  return size > 8;
+  return (size > 8 || size == 0);
 }
 
 /* Return an RTX to represent where a value with mode MODE will be returned
@@ -1598,6 +1600,37 @@ mn10300_arg_partial_bytes (CUMULATIVE_ARGS *cum, enum machine_mode mode,
   return nregs * UNITS_PER_WORD - cum->nbytes;
 }
 
+/* Return the location of the function's value.  This will be either
+   $d0 for integer functions, $a0 for pointers, or a PARALLEL of both
+   $d0 and $a0 if the -mreturn-pointer-on-do flag is set.  Note that
+   we only return the PARALLEL for outgoing values; we do not want
+   callers relying on this extra copy.  */
+
+rtx
+mn10300_function_value (tree valtype, tree func, int outgoing)
+{
+  rtx rv;
+  enum machine_mode mode = TYPE_MODE (valtype);
+
+  if (! POINTER_TYPE_P (valtype))
+    return gen_rtx_REG (mode, FIRST_DATA_REGNUM);
+  else if (! TARGET_PTR_A0D0 || ! outgoing
+	   || current_function_returns_struct)
+    return gen_rtx_REG (mode, FIRST_ADDRESS_REGNUM);
+
+  rv = gen_rtx_PARALLEL (mode, rtvec_alloc (2));
+  XVECEXP (rv, 0, 0)
+    = gen_rtx_EXPR_LIST (VOIDmode,
+			 gen_rtx_REG (mode, FIRST_ADDRESS_REGNUM),
+			 GEN_INT (0));
+  
+  XVECEXP (rv, 0, 1)
+    = gen_rtx_EXPR_LIST (VOIDmode,
+			 gen_rtx_REG (mode, FIRST_DATA_REGNUM),
+			 GEN_INT (0));
+  return rv;
+}
+
 /* Output a tst insn.  */
 const char *
 output_tst (rtx operand, rtx insn)
diff --git a/gcc/config/mn10300/mn10300.h b/gcc/config/mn10300/mn10300.h
index 20751fd18a0..b102c398306 100644
--- a/gcc/config/mn10300/mn10300.h
+++ b/gcc/config/mn10300/mn10300.h
@@ -594,8 +594,9 @@ struct cum_arg {int nbytes; };
    otherwise, FUNC is 0.  */
 
 #define FUNCTION_VALUE(VALTYPE, FUNC) \
-  gen_rtx_REG (TYPE_MODE (VALTYPE), POINTER_TYPE_P (VALTYPE) \
-	       ? FIRST_ADDRESS_REGNUM : FIRST_DATA_REGNUM)
+  mn10300_function_value (VALTYPE, FUNC, 0)
+#define FUNCTION_OUTGOING_VALUE(VALTYPE, FUNC) \
+  mn10300_function_value (VALTYPE, FUNC, 1)
 
 /* Define how to find the value returned by a library function
    assuming the value has mode MODE.  */
diff --git a/gcc/config/mn10300/mn10300.opt b/gcc/config/mn10300/mn10300.opt
index bc697045f84..7e0658c495c 100644
--- a/gcc/config/mn10300/mn10300.opt
+++ b/gcc/config/mn10300/mn10300.opt
@@ -35,3 +35,7 @@ Work around hardware multiply bug
 mrelax
 Target RejectNegative
 Enable linker relaxations
+
+mreturn-pointer-on-d0
+Target Report Mask(PTR_A0D0)
+Return pointers in both a0 and d0