rs6000-protos.h (rs6000_find_base_term): Declare.

gcc/
	* config/rs6000/rs6000-protos.h (rs6000_find_base_term): Declare.
	* config/rs6000/rs6000.h (FIND_BASE_TERM): New macro.
	* config/rs6000/rs6000.c (rs6000_find_base_term): New function.

From-SVN: r140912

gcc/ChangeLog

 2008-10-06  Richard Sandiford  <rdsandiford@googlemail.com>
 
+	* config/rs6000/rs6000-protos.h (rs6000_find_base_term): Declare.
+	* config/rs6000/rs6000.h (FIND_BASE_TERM): New macro.
+	* config/rs6000/rs6000.c (rs6000_find_base_term): New function.
+
+2008-10-06  Richard Sandiford  <rdsandiford@googlemail.com>
+
 	* config/darwin-protos.h (machopic_function_base_name): Delete.
 	(machopic_function_base_sym): Likewise.
 	(machopic_gen_offset): Declare.

gcc/config/rs6000/rs6000-protos.h

@@ -112,6 +112,7 @@ extern rtx rs6000_legitimize_reload_address (rtx, enum machine_mode,
 extern int rs6000_legitimate_address (enum machine_mode, rtx, int);
 extern bool rs6000_legitimate_offset_address_p (enum machine_mode, rtx, int);
 extern bool rs6000_mode_dependent_address (rtx);
+extern rtx rs6000_find_base_term (rtx);
 extern bool rs6000_offsettable_memref_p (rtx);
 extern rtx rs6000_return_addr (int, rtx);
 extern void rs6000_output_symbol_ref (FILE*, rtx);

gcc/config/rs6000/rs6000.c

@@ -4455,6 +4455,27 @@ rs6000_mode_dependent_address (rtx addr)
   return false;
 }
 
+/* Implement FIND_BASE_TERM.  */
+
+rtx
+rs6000_find_base_term (rtx op)
+{
+  rtx base, offset;
+
+  split_const (op, &base, &offset);
+  if (GET_CODE (base) == UNSPEC)
+    switch (XINT (base, 1))
+      {
+      case UNSPEC_TOCREL:
+      case UNSPEC_MACHOPIC_OFFSET:
+	/* OP represents SYM [+ OFFSET] - ANCHOR.  SYM is the base term
+	   for aliasing purposes.  */
+	return XVECEXP (base, 0, 0);
+      }
+
+  return op;
+}
+
 /* More elaborate version of recog's offsettable_memref_p predicate
    that works around the ??? note of rs6000_mode_dependent_address.
    In particular it accepts

gcc/config/rs6000/rs6000.h

@@ -1856,6 +1856,8 @@ do {								\
   if (rs6000_mode_dependent_address (ADDR))			\
     goto LABEL;							\
 } while (0)
+
+#define FIND_BASE_TERM rs6000_find_base_term
 
 /* The register number of the register used to address a table of
    static data addresses in memory.  In some cases this register is