PowerPC instruction operand flag validation

[Alan Modra]

This adds another check that might have saved me a little time
recently if it had been present.

	* config/tc-ppc.c (insn_validate): Check that optional operands
	are not followed by non-optional operands.

diff --git a/gas/config/tc-ppc.c b/gas/config/tc-ppc.c
index d587a50ca7..694c47ad1f 100644
--- a/gas/config/tc-ppc.c
+++ b/gas/config/tc-ppc.c
@@ -1514,6 +1514,7 @@ insn_validate (const struct powerpc_opcode *op)
   /* The operands must not overlap the opcode or each other.  */
   for (o = op->operands; *o; ++o)
     {
+      bfd_boolean optional = FALSE;
       if (*o >= num_powerpc_operands)
         {
 	  as_bad (_("operand index error for %s"), op->name);
@@ -1538,6 +1539,14 @@ insn_validate (const struct powerpc_opcode *op)
 		}
 	      omask |= mask;
 	    }
+	  if ((operand->flags & PPC_OPERAND_OPTIONAL) != 0)
+	    optional = TRUE;
+	  else if (optional)
+	    {
+	      as_bad (_("non-optional operand %d follows optional operand in %s"),
+		      (int) (o - op->operands), op->name);
+	      return TRUE;
+	    }
         }
     }
   return FALSE;

-- 
Alan Modra
Australia Development Lab, IBM