diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 796b2080944..86f674efd7d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2001-08-29  Kazu Hirata  <kazu@hxi.com>
+
+	* h8300.md (anonymous movhi pattern): Don't move (reg n) to
+	(mem (pre_dec (reg n))
+	(anonymous movsi pattern): Likewise.
+
 2001-08-29  Kazu Hirata  <kazu@hxi.com>
 
 	* h8300.h (RETURN_ADDR_RTX): New.
diff --git a/gcc/config/h8300/h8300.md b/gcc/config/h8300/h8300.md
index 216524ec070..b8a9b5e0a99 100644
--- a/gcc/config/h8300/h8300.md
+++ b/gcc/config/h8300/h8300.md
@@ -175,7 +175,12 @@
 	(match_operand:HI 1 "general_operand_src" "I,r>,r,i,m,r"))]
   "TARGET_H8300
    && (register_operand (operands[0],HImode)
-       || register_operand (operands[1], HImode))"
+       || register_operand (operands[1], HImode))
+   && !(GET_CODE (operands[0]) == MEM
+	&& GET_CODE (XEXP (operands[0], 0)) == PRE_DEC
+	&& GET_CODE (XEXP (XEXP (operands[0], 0), 0)) == REG
+	&& GET_CODE (operands[1]) == REG
+	&& REGNO (XEXP (XEXP (operands[0], 0), 0)) == REGNO (operands[1]))"
   "@
    sub.w	%T0,%T0
    mov.w	%T1,%T0
@@ -404,7 +409,12 @@
 	(match_operand:SI 1 "general_operand_src" "I,r,i,m,r,r,>,I,r,*a"))]
   "(TARGET_H8300S || TARGET_H8300H)
    && (register_operand (operands[0], SImode)
-       || register_operand (operands[1], SImode))"
+       || register_operand (operands[1], SImode))
+   && !(GET_CODE (operands[0]) == MEM
+	&& GET_CODE (XEXP (operands[0], 0)) == PRE_DEC
+	&& GET_CODE (XEXP (XEXP (operands[0], 0), 0)) == REG
+	&& GET_CODE (operands[1]) == REG
+	&& REGNO (XEXP (XEXP (operands[0], 0), 0)) == REGNO (operands[1]))"
   "*
 {
   switch (which_alternative)