gas/

* config/tc-mips.c (match_expression):  Report uses of registers here.
	Add a "must be an immediate expression" error.  Handle elided offsets
	here rather than...
	(match_int_operand): ...here.

gas/testsuite/
	* gas/mips/octeon-ill.l: Adjust expected output.
	* gas/mips/lui-1.l, gas/mips/lui-1.s: Add more cases.

gas/ChangeLog

@@ -1,3 +1,10 @@
+2013-08-19  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	* config/tc-mips.c (match_expression):  Report uses of registers here.
+	Add a "must be an immediate expression" error.  Handle elided offsets
+	here rather than...
+	(match_int_operand): ...here.
+
 2013-08-19  Richard Sandiford  <rdsandiford@googlemail.com>
 
 	* config/tc-mips.c (mips_arg_info): Remove soft_match.

gas/config/tc-mips.c

@@ -4325,6 +4325,26 @@ static bfd_boolean
 match_expression (struct mips_arg_info *arg, expressionS *value,
 		  bfd_reloc_code_real_type *r)
 {
+  /* If the next token is a '(' that was parsed as being part of a base
+     expression, assume we have an elided offset.  The later match will fail
+     if this turns out to be wrong.  */
+  if (arg->token->type == OT_CHAR && arg->token->u.ch == '(')
+    {
+      value->X_op = O_constant;
+      value->X_add_number = 0;
+      r[0] = r[1] = r[2] = BFD_RELOC_UNUSED;
+      return TRUE;
+    }
+
+  /* Reject register-based expressions such as "0+$2" and "(($2))".
+     For plain registers the default error seems more appropriate.  */
+  if (arg->token->type == OT_INTEGER
+      && arg->token->u.integer.value.X_op == O_register)
+    {
+      set_insn_error (arg->argnum, _("register value used as expression"));
+      return FALSE;
+    }
+
   if (arg->token->type == OT_INTEGER)
     {
       *value = arg->token->u.integer.value;
@@ -4333,29 +4353,10 @@ match_expression (struct mips_arg_info *arg, expressionS *value,
       return TRUE;
     }
 
-  /* Error-reporting is more consistent if we treat registers as O_register
-     rather than rejecting them outright.  "$1", "($1)" and "(($1))" are
-     then handled in the same way.  */
-  if (arg->token->type == OT_REG)
-    {
-      value->X_add_number = arg->token->u.regno;
-      ++arg->token;
-    }
-  else if (arg->token[0].type == OT_CHAR
-	   && arg->token[0].u.ch == '('
-	   && arg->token[1].type == OT_REG
-	   && arg->token[2].type == OT_CHAR
-	   && arg->token[2].u.ch == ')')
-    {
-      value->X_add_number = arg->token[1].u.regno;
-      arg->token += 3;
-    }
-  else
-    return FALSE;
-
-  value->X_op = O_register;
-  r[0] = r[1] = r[2] = BFD_RELOC_UNUSED;
-  return TRUE;
+  set_insn_error_i
+    (arg->argnum, _("operand %d must be an immediate expression"),
+     arg->argnum);
+  return FALSE;
 }
 
 /* Try to get a constant expression from the next tokens in ARG.  Consume
@@ -4561,15 +4562,11 @@ match_int_operand (struct mips_arg_info *arg,
   if (arg->lax_max)
     max_val = ((1 << operand_base->size) - 1) << operand->shift;
 
-  if (arg->token->type == OT_CHAR && arg->token->u.ch == '(')
-    /* Assume we have an elided offset.  The later match will fail
-       if this turns out to be wrong.  */
-    sval = 0;
-  else if (operand_base->lsb == 0
-	   && operand_base->size == 16
-	   && operand->shift == 0
-	   && operand->bias == 0
-	   && (operand->max_val == 32767 || operand->max_val == 65535))
+  if (operand_base->lsb == 0
+      && operand_base->size == 16
+      && operand->shift == 0
+      && operand->bias == 0
+      && (operand->max_val == 32767 || operand->max_val == 65535))
     {
       /* The operand can be relocated.  */
       if (!match_expression (arg, &offset_expr, offset_reloc))

gas/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2013-08-19  Richard Sandiford  <rdsandiford@googlemail.com>
+
+	* gas/mips/octeon-ill.l: Adjust expected output.
+	* gas/mips/lui-1.l, gas/mips/lui-1.s: Add more cases.
+
 2013-08-19  Richard Sandiford  <rdsandiford@googlemail.com>
 
 	* gas/mips/ext-ill.l, gas/mips/lui-1.l, gas/mips/mips16e-64.l,

gas/testsuite/gas/mips/lui-1.l

@@ -2,4 +2,7 @@
 .*\.s:5: Error: operand 2 out of range `lui \$2,-1'
 .*\.s:6: Error: operand 2 out of range `lui \$2,65536'
 .*\.s:7: Error: bignum invalid
-.*\.s:8: Error: register value used as expression
+.*\.s:8: Error: operand 2 must be an immediate expression `lui \$2,\$3'
+.*\.s:9: Error: Illegal operands `lui \$2,\(\$3\)'
+.*\.s:10: Error: register value used as expression `lui \$2,0\+\$3'
+.*\.s:11: Error: register value used as expression `lui \$2,\(\(\$3\)\)'

gas/testsuite/gas/mips/lui-1.s

@@ -6,3 +6,6 @@ foo:
 	lui	$2, 65536
 	lui	$2, 0x10000000000000000
 	lui	$2, $3
+	lui	$2, ($3)
+	lui	$2, 0+$3
+	lui	$2, (($3))

gas/testsuite/gas/mips/octeon-ill.l

@@ -30,10 +30,10 @@
 .*:43: Error: Opcode not supported on this processor.*
 .*:45: Error: operand 2 out of range `dmfc2 \$2,0x10000'
 .*:46: Error: operand 2 out of range `dmtc2 \$2,0x12345'
-.*:47: Error: operand 2 must be constant `dmfc2 \$9,\$12'
-.*:48: Error: operand 2 must be constant `dmfc2 \$4,\$15,4'
-.*:49: Error: operand 2 must be constant `dmtc2 \$16,\$8'
-.*:50: Error: operand 2 must be constant `dmtc2 \$22,\$7,\$4'
+.*:47: Error: operand 2 must be an immediate expression `dmfc2 \$9,\$12'
+.*:48: Error: operand 2 must be an immediate expression `dmfc2 \$4,\$15,4'
+.*:49: Error: operand 2 must be an immediate expression `dmtc2 \$16,\$8'
+.*:50: Error: operand 2 must be an immediate expression `dmtc2 \$22,\$7,\$4'
 .*:52: Error: operand 3 out of range `exts \$26,26,32'
 .*:54: Error: operand 3 out of range `exts32 \$7,\$21,32,10'
 .*:55: Error: operand 4 out of range `exts32 \$31,\$13,3,29'