diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5e0b4534b2ec..625fa6ac20ba 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,9 @@
 2005-05-18  Geoffrey Keating  <geoffk@apple.com>
 
+	* rs6000/predicates.md (fix_trunc_dest_operand): New.
+	* rs6000/rs6000.md (fix_truncdfsi2): Use fix_trunc_dest_operand.
+	Check that a memory operand is valid before trying to use it.
+	
 	* tree-cfg.c (pass_remove_useless): This pass works on trees.
 
 2005-05-18  Richard Guenther  <rguenth@gcc.gnu.org>
diff --git a/gcc/config/rs6000/predicates.md b/gcc/config/rs6000/predicates.md
index 05db033089af..570f59d3f0ce 100644
--- a/gcc/config/rs6000/predicates.md
+++ b/gcc/config/rs6000/predicates.md
@@ -364,6 +364,15 @@
 		    || GET_CODE (XEXP (XEXP (op, 0), 1)) != CONST_INT
 		    || INTVAL (XEXP (XEXP (op, 0), 1)) % 4 == 0")))
 
+;; Used for the destination of the fix_truncdfsi2 expander.
+;; If stfiwx will be used, the result goes to memory; otherwise,
+;; we're going to emit a store and a load of a subreg, so the dest is a
+;; register.
+(define_predicate "fix_trunc_dest_operand"
+  (if_then_else (match_test "! TARGET_E500_DOUBLE && TARGET_PPC_GFXOPT")
+   (match_operand 0 "memory_operand")
+   (match_operand 0 "gpc_reg_operand")))
+
 ;; Return 1 if the operand is either a non-special register or can be used
 ;; as the operand of a `mode' add insn.
 (define_predicate "add_operand"
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index c627daf2d777..b53792c32ae2 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -5329,10 +5329,8 @@
 }"
   [(set_attr "length" "20")])
 
-; In the TARGET_PPC_GFXOPT case, this could and probably should
-; take a memory destination; but actually making this work is hard.
 (define_expand "fix_truncdfsi2"
-  [(parallel [(set (match_operand:SI 0 "gpc_reg_operand" "")
+  [(parallel [(set (match_operand:SI 0 "fix_trunc_dest_operand" "")
 		   (fix:SI (match_operand:DF 1 "gpc_reg_operand" "")))
 	      (clobber (match_dup 2))
 	      (clobber (match_dup 3))])]
@@ -5349,7 +5347,7 @@
   if (TARGET_PPC_GFXOPT)
     {
       rtx orig_dest = operands[0];
-      if (GET_CODE (orig_dest) != MEM)
+      if (! memory_operand (orig_dest, GET_MODE (orig_dest)))
 	operands[0] = assign_stack_temp (SImode, GET_MODE_SIZE (SImode), 0);
       emit_insn (gen_fix_truncdfsi2_internal_gfxopt (operands[0], operands[1],
 						     operands[2]));