[turbofan] Avoid using the typer's types in representation inference for phis.

src/compiler/representation-change.cc

 // Copyright 2015 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 "src/compiler/representation-change.h"
 
 #include <sstream>
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 46 matching lines @@
 Truncation::TruncationKind Truncation::Generalize(TruncationKind rep1,
                                                   TruncationKind rep2) {
   if (LessGeneral(rep1, rep2)) return rep2;
   if (LessGeneral(rep2, rep1)) return rep1;
   // Handle the generalization of float64-representable values.
   if (LessGeneral(rep1, TruncationKind::kFloat64) &&
       LessGeneral(rep2, TruncationKind::kFloat64)) {
     return TruncationKind::kFloat64;
   }
   // All other combinations are illegal.
-  FATAL("Tried to combine incompatible representations");
+  FATAL("Tried to combine incompatible truncations");
   return TruncationKind::kNone;
 }
 
 
 // static
 bool Truncation::LessGeneral(TruncationKind rep1, TruncationKind rep2) {
   switch (rep1) {
     case TruncationKind::kNone:
       return true;
     case TruncationKind::kBool:
@@ skipping 450 matching lines @@
 
 
 Node* RepresentationChanger::InsertChangeTaggedToFloat64(Node* node) {
   return jsgraph()->graph()->NewNode(simplified()->ChangeTaggedToFloat64(),
                                      node);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8