Assume signed for converting to word32/float64 unless use or output is explicitly unsigned.

test/cctest/compiler/test-representation-change.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits>
 
 #include "src/v8.h"
 #include "test/cctest/cctest.h"
 #include "test/cctest/compiler/graph-builder-tester.h"
 
@@ skipping 174 matching lines @@
   CheckChange(IrOpcode::kChangeInt32ToFloat64, rWord32 | tInt32, rFloat64);
   CheckChange(IrOpcode::kChangeUint32ToFloat64, rWord32 | tUint32, rFloat64);
   CheckChange(IrOpcode::kChangeFloat64ToInt32, rFloat64 | tInt32, rWord32);
   CheckChange(IrOpcode::kChangeFloat64ToUint32, rFloat64 | tUint32, rWord32);
 }
 
 
 TEST(SignednessInWord32) {
   RepresentationChangerTester r;
 
-  // TODO(titzer): these are currently type errors because the output type is
-  // not specified. Maybe the RepresentationChanger should assume anything to or
-  // from {rWord32} is {tInt32}, i.e. signed, if not it is explicitly otherwise?
-  r.CheckTypeError(rTagged, rWord32 | tInt32);
-  r.CheckTypeError(rTagged, rWord32 | tUint32);
-  r.CheckTypeError(rWord32, rFloat64);
-  r.CheckTypeError(rFloat64, rWord32);
-
-  //  CheckChange(IrOpcode::kChangeTaggedToInt32, rTagged, rWord32 | tInt32);
-  //  CheckChange(IrOpcode::kChangeTaggedToUint32, rTagged, rWord32 | tUint32);
-  //  CheckChange(IrOpcode::kChangeInt32ToFloat64, rWord32, rFloat64);
-  //  CheckChange(IrOpcode::kChangeFloat64ToInt32, rFloat64, rWord32);
+  // TODO(titzer): assume that uses of a word32 without a sign mean tInt32.
+  CheckChange(IrOpcode::kChangeTaggedToInt32, rTagged, rWord32 | tInt32);
+  CheckChange(IrOpcode::kChangeTaggedToUint32, rTagged, rWord32 | tUint32);
+  CheckChange(IrOpcode::kChangeInt32ToFloat64, rWord32, rFloat64);
+  CheckChange(IrOpcode::kChangeFloat64ToInt32, rFloat64, rWord32);
 }
 
 
 TEST(Nops) {
   RepresentationChangerTester r;
 
   // X -> X is always a nop for any single representation X.
   for (size_t i = 0; i < ARRAY_SIZE(all_reps); i++) {
     r.CheckNop(all_reps[i], all_reps[i]);
   }
@@ skipping 57 matching lines @@
   // rW64
   // tIrW64
   // tUrW64
   // rF64
   // tIrF64
   // tUrF64
   // tArF64
   // rT
   // tArT
 }