[turbofan] Run representation selection without the Typer decorator.

src/compiler/pipeline.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 "src/compiler/pipeline.h"
 
 #include <fstream>  // NOLINT(readability/streams)
 #include <sstream>
 
 #include "src/base/adapters.h"
@@ skipping 1426 matching lines @@
 
     if (FLAG_turbo_stress_loop_peeling) {
       Run<StressLoopPeelingPhase>();
       RunPrintAndVerify("Loop peeled");
     }
 
     if (FLAG_turbo_escape) {
       Run<EscapeAnalysisPhase>();
       RunPrintAndVerify("Escape Analysed");
     }
+  }
 
-    // Select representations.
-    Run<RepresentationSelectionPhase>();
-    RunPrintAndVerify("Representations selected", true);
-  }
+  // Select representations. This has to run w/o the Typer decorator, because
+  // we cannot compute meaningful types anyways, and the computed types might
+  // even conflict with the representation/truncation logic.
+  Run<RepresentationSelectionPhase>();
+  RunPrintAndVerify("Representations selected", true);
 
 #ifdef DEBUG
   // From now on it is invalid to look at types on the nodes, because:
   //
   //  (a) The remaining passes (might) run concurrent to the main thread and
   //      therefore must not access the Heap or the Isolate in an uncontrolled
   //      way (as done by the type system), and
   //  (b) the types on the nodes might not make sense after representation
   //      selection due to the way we handle truncations; if we'd want to look
   //      at types afterwards we'd essentially need to re-type (large portions
@@ skipping 367 matching lines @@
   data->DeleteRegisterAllocationZone();
 }
 
 CompilationInfo* PipelineImpl::info() const { return data_->info(); }
 
 Isolate* PipelineImpl::isolate() const { return info()->isolate(); }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8