(record_reg_classes): Ignore leading % when examining constraint.

Don't bypass usual cost computation when a pseudo "matches"
a non-pseudo in matching operands.

From-SVN: r2123

gcc/regclass.c

@@ -910,6 +910,9 @@ record_reg_classes (n_alts, n_ops, ops, modes, constraints, insn)
 	      continue;
 	    }
 
+	  if (*p == '%')
+	    p++;
+
 	  /* If this alternative is only relevant when this operand
 	     matches a previous operand, we do different things depending
 	     on whether this operand is a pseudo-reg or not.  */
@@ -967,9 +970,11 @@ record_reg_classes (n_alts, n_ops, ops, modes, constraints, insn)
 		  this_op_costs[i] = this_op_costs[j];
 		  if (! find_reg_note (insn, REG_DEAD, op))
 		    alt_cost += 2;
-		}
 
-	      continue;
+		  /* This is in place of ordinary cost computation
+		     for this operand.  */
+		  continue;
+		}
 	    }
 
 	  /* Scan all the constraint letters.  See if the operand matches