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

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

Index: test/cctest/compiler/test-representation-change.cc
diff --git a/test/cctest/compiler/test-representation-change.cc b/test/cctest/compiler/test-representation-change.cc
index d28cf4b4b82001c1473a3149cf85bd5a68bc4d00..092a5f7d90cab204aa9fe1a055240f87d382b0f4 100644
--- a/test/cctest/compiler/test-representation-change.cc
+++ b/test/cctest/compiler/test-representation-change.cc
@@ -192,18 +192,11 @@ TEST(SingleChanges) {
 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);
 }