diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6cb1973c0ee..209ab0d63d9 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,15 @@
+2006-10-04  Zack Weinberg  <zackw@panix.com>
+
+	Fix bug in constraint-check generator, reported by Rask Ingemann
+	Lambertsen:
+	* genpreds.c (add_constraint): Don't remove anything from the
+	expression here.
+	(write_tm_constrs_h): Detect whether "op" argument is used, and
+	mark it ARG_UNUSED if it isn't.
+	(write_insn_const_int_ok_for_constraint): Skip the part of the
+	expression that would test whether "op" (which is not available
+	here) is a CONST_INT.
+
 2006-10-04  Ryan Mansfield  <rmansfield@qnx.com>
 
 	PR c++/28448
@@ -42,7 +54,7 @@
 2006-10-01  Ryan Mansfield  <rmansfield@qnx.com>
 
 	PR c/20533
-	* doc/extend.texi: Add used variable attribute description. 
+	* doc/extend.texi: Add used variable attribute description.
 
 2006-09-30  Joseph S. Myers  <joseph@codesourcery.com>
 
@@ -4040,7 +4052,7 @@
 	range of a REG_DEAD register.
 
 2006-18-05  Joerg Wunsch <j.gnu@uriah.heep.sax.de>
-            Anatoly Sokolov <aesok@post.ru>
+	    Anatoly Sokolov <aesok@post.ru>
 
 	* config/avr/avr.c (avr_mcu_types): Add support for attiny261,
 	attiny461, attiny861, attiny25, attiny45, attiny85, attiny24,
@@ -4157,7 +4169,7 @@
 	* config/pa/pa-linux.h (STRING_ASM_OP): Prepend and append a tab.
 
 2006-05-19  Daniel Berlin  <dberlin@dberlin.org>
-            Kenneth Zadeck <zadeck@naturalbridge.com>
+	    Kenneth Zadeck <zadeck@naturalbridge.com>
 
 	PR rtl-optimization/26855
 
@@ -6555,7 +6567,7 @@
 2006-04-04  Matthias Klose  <doko@debian.org>
 
 	* Makefile.in (unprotoize.o): Same dependencies as for protoize.o.
-	
+
 	PR bootstrap/26764
 	PR bootstrap/27334
 	* Makefile.in (s-macro_list): Conform to POSIX rules in single quoted
diff --git a/gcc/genpreds.c b/gcc/genpreds.c
index adc3e48372b..535c9ddde77 100644
--- a/gcc/genpreds.c
+++ b/gcc/genpreds.c
@@ -891,10 +891,6 @@ add_constraint (const char *name, const char *regclass,
 	  have_error = 1;
 	  return;
 	}
-
-      /* Remove the redundant (and (match_code "const_(int|double)")
-	 from the expression.  */
-      exp = XEXP (exp, 1);
     }
 
   
@@ -1078,10 +1074,13 @@ write_tm_constrs_h (void)
 	bool needs_rval = needs_variable (c->exp, "rval");
 	bool needs_mode = (needs_variable (c->exp, "mode")
 			   || needs_hval || needs_lval || needs_rval);
+	bool needs_op = (needs_variable (c->exp, "op")
+			 || needs_ival || needs_mode);
 
 	printf ("static inline bool\n"
-		"satisfies_constraint_%s (rtx op)\n"
-		"{\n", c->c_name);
+		"satisfies_constraint_%s (rtx %s)\n"
+		"{\n", c->c_name,
+		needs_op ? "op" : "ARG_UNUSED (op)");
 	if (needs_mode)
 	  puts ("enum machine_mode mode = GET_MODE (op);");
 	if (needs_ival)
@@ -1157,7 +1156,10 @@ write_insn_const_int_ok_for_constraint (void)
     if (c->is_const_int)
       {
 	printf ("    case CONSTRAINT_%s:\n      return ", c->c_name);
-	write_predicate_expr (c->exp);
+	/* c->exp is guaranteed to be (and (match_code "const_int") (...));
+	   we know at this point that we have a const_int, so we need not
+	   bother with that part of the test.  */
+	write_predicate_expr (XEXP (c->exp, 1));
 	fputs (";\n\n", stdout);
       }