simplify_exprt::simplify_bitwise: hoist a power(...) expression

Daniel Kroening · Daniel Kroening · commit b2390e41ce03 · 2018-10-19T11:21:27.000+01:00
diff --git a/src/util/simplify_expr_int.cpp b/src/util/simplify_expr_int.cpp
@@ -781,16 +781,16 @@ bool simplify_exprt::simplify_bitwise(exprt &expr)
 
   if(expr.id()==ID_bitand)
   {
+    const auto all_ones = power(2, width) - 1;
     for(exprt::operandst::iterator
         it=expr.operands().begin();
         it!=expr.operands().end();
         ) // no it++
     {
       if(
         it->is_constant() &&
-        bvrep2integer(
-          to_constant_expr(*it).get_value(), width, false) ==
-          power(2, width) - 1 &&
+        bvrep2integer(to_constant_expr(*it).get_value(), width, false) ==
+          all_ones &&
         expr.operands().size() > 1)
       {
         it=expr.operands().erase(it);

Original file line number	Diff line number	Diff line change
`@@ -781,16 +781,16 @@ bool simplify_exprt::simplify_bitwise(exprt &expr)`
`781`	`781`
`782`	`782`	`if(expr.id()==ID_bitand)`
`783`	`783`	`{`
	`784`	`+ const auto all_ones = power(2, width) - 1;`
`784`	`785`	`for(exprt::operandst::iterator`
`785`	`786`	`it=expr.operands().begin();`
`786`	`787`	`it!=expr.operands().end();`
`787`	`788`	`) // no it++`
`788`	`789`	`{`
`789`	`790`	`if(`
`790`	`791`	`it->is_constant() &&`
`791`		`- bvrep2integer(`
`792`		`- to_constant_expr(*it).get_value(), width, false) ==`
`793`		`- power(2, width) - 1 &&`
	`792`	`+ bvrep2integer(to_constant_expr(*it).get_value(), width, false) ==`
	`793`	`+ all_ones &&`
`794`	`794`	`expr.operands().size() > 1)`
`795`	`795`	`{`
`796`	`796`	`it=expr.operands().erase(it);`