diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 27e5ec23409..4d851c0b170 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2020-01-24  Jeff Law  <law@redhat.com>
+
+	PR target/13721
+	* config/h8300/h8300.c (h8300_print_operand): Only call byte_reg
+	for REGs.  Call output_operand_lossage to get more reasonable
+	diagnostics.
+
 2020-01-24  Andrew Stubbs  <ams@codesourcery.com>
 
 	* config/gcn/gcn-valu.md (vec_cmp<mode>di): Use
diff --git a/gcc/config/h8300/h8300.c b/gcc/config/h8300/h8300.c
index ffbfa9eaaa9..def8be344af 100644
--- a/gcc/config/h8300/h8300.c
+++ b/gcc/config/h8300/h8300.c
@@ -1647,40 +1647,52 @@ h8300_print_operand (FILE *file, rtx x, int code)
     case 's':
       if (GET_CODE (x) == CONST_INT)
 	fprintf (file, "#%ld", (INTVAL (x)) & 0xff);
-      else
+      else if (GET_CODE (x) == REG)
 	fprintf (file, "%s", byte_reg (x, 0));
+      else
+	output_operand_lossage ("Expected register or constant integer.");
       break;
     case 't':
       if (GET_CODE (x) == CONST_INT)
 	fprintf (file, "#%ld", (INTVAL (x) >> 8) & 0xff);
-      else
+      else if (GET_CODE (x) == REG)
 	fprintf (file, "%s", byte_reg (x, 1));
+      else
+	output_operand_lossage ("Expected register or constant integer.");
       break;
     case 'w':
       if (GET_CODE (x) == CONST_INT)
 	fprintf (file, "#%ld", INTVAL (x) & 0xff);
-      else
+      else if (GET_CODE (x) == REG)
 	fprintf (file, "%s",
 		 byte_reg (x, TARGET_H8300 ? 2 : 0));
+      else
+	output_operand_lossage ("Expected register or constant integer.");
       break;
     case 'x':
       if (GET_CODE (x) == CONST_INT)
 	fprintf (file, "#%ld", (INTVAL (x) >> 8) & 0xff);
-      else
+      else if (GET_CODE (x) == REG)
 	fprintf (file, "%s",
 		 byte_reg (x, TARGET_H8300 ? 3 : 1));
+      else
+	output_operand_lossage ("Expected register or constant integer.");
       break;
     case 'y':
       if (GET_CODE (x) == CONST_INT)
 	fprintf (file, "#%ld", (INTVAL (x) >> 16) & 0xff);
-      else
+      else if (GET_CODE (x) == REG)
 	fprintf (file, "%s", byte_reg (x, 0));
+      else
+	output_operand_lossage ("Expected register or constant integer.");
       break;
     case 'z':
       if (GET_CODE (x) == CONST_INT)
 	fprintf (file, "#%ld", (INTVAL (x) >> 24) & 0xff);
-      else
+      else if (GET_CODE (x) == REG)
 	fprintf (file, "%s", byte_reg (x, 1));
+      else
+	output_operand_lossage ("Expected register or constant integer.");
       break;
 
     default:
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c465ff99541..c0699907f1c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-01-24  Jeff Law  <law@redhat.com
+
+	PR target/13721
+	* gcc.target/h8300/pr13721.c: New test.
+
 2020-01-24  Christophe Lyon  <christophe.lyon@linaro.org>
 
 	PR debug/92763
diff --git a/gcc/testsuite/gcc.target/h8300/pr13721.c b/gcc/testsuite/gcc.target/h8300/pr13721.c
new file mode 100644
index 00000000000..817b5377448
--- /dev/null
+++ b/gcc/testsuite/gcc.target/h8300/pr13721.c
@@ -0,0 +1,71 @@
+static __inline__ __attribute__((always_inline)) void set_bit(int nr, volatile void * addr) 
+{
+	volatile unsigned char *b_addr;
+	b_addr = (volatile unsigned char *)addr + ((nr >> 3) ^ 3);
+	nr &= 7;
+	if (__builtin_constant_p (nr))					  
+	{								  
+		switch(nr)						  
+		{							  
+		case 0:							  
+			__asm__("bset #0,%0" :"+m"(*b_addr) :"m"(*b_addr));
+			break;	     					  
+		case 1:		     					  
+			__asm__("bset #1,%0" :"+m"(*b_addr) :"m"(*b_addr));
+			break;	     					  
+		case 2:		     					  
+			__asm__("bset #2,%0" :"+m"(*b_addr) :"m"(*b_addr));
+			break;	     					  
+		case 3:		     					  
+			__asm__("bset #3,%0" :"+m"(*b_addr) :"m"(*b_addr));
+			break;	     					  
+		case 4:		     					  
+			__asm__("bset #4,%0" :"+m"(*b_addr) :"m"(*b_addr));
+			break;	     					  
+		case 5:		     					  
+			__asm__("bset #5,%0" :"+m"(*b_addr) :"m"(*b_addr));
+			break;	     					  
+		case 6:		     					  
+			__asm__("bset #6,%0" :"+m"(*b_addr) :"m"(*b_addr));
+			break;	     					  
+		case 7:		     					  
+			__asm__("bset #7,%0" :"+m"(*b_addr) :"m"(*b_addr));
+			break;						  
+		}							  
+	}								  
+	else								  
+	{								  
+		__asm__("bset %w1,%0"  :"+m"(*b_addr)  :"g"(nr),"m"(*b_addr));	/* { dg-error "invalid 'asm'" "" } */
+
+	}								  
+}
+
+static __inline__ __attribute__((always_inline)) int test_bit(int nr, const volatile void * addr)
+{
+	return (*((volatile unsigned char *)addr + ((nr >> 3) ^ 3)) & (1UL << (nr & 7))) != 0;
+}
+
+struct a {
+        unsigned long a;
+};
+
+void dummy(struct a *a, int b);
+
+int ice_func(struct a *a, int b)
+{
+  int c,d;
+  unsigned int e;
+
+  for(c=0;c<b;c++) {
+    for(d=b; d <= b; d++) {
+      if (!test_bit(d, &e)) {
+        dummy(a, d * a->a);
+        dummy(a, d * a->a);
+        set_bit(d, &e);
+      }
+    }
+    dummy(a, d * a->a);
+  }
+
+  return 0;
+}
