[turbofan] Simplify and fix JS typed lowering type init.

src/compiler/js-typed-lowering.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/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/operator-properties.h"
@@ skipping 20 matching lines @@
 // Relax the control uses of {node} by immediately replacing them with the
 // control input to {node}.
 // TODO(titzer): move into a GraphEditor?
 static void RelaxControls(Node* node) {
   NodeProperties::ReplaceWithValue(node, node, node);
 }
 
 
 JSTypedLowering::JSTypedLowering(JSGraph* jsgraph, Zone* zone)
     : jsgraph_(jsgraph), simplified_(graph()->zone()), conversions_(zone) {
-  zero_range_ = Type::Range(0.0, 1.0, graph()->zone());
+  zero_range_ = Type::Range(0.0, 0.0, graph()->zone());
   one_range_ = Type::Range(1.0, 1.0, graph()->zone());
   zero_thirtyone_range_ = Type::Range(0.0, 31.0, graph()->zone());
-  // TODO(jarin): Can we have a correctification of the stupid type system?
-  // These stupid work-arounds are just stupid!
-  shifted_int32_ranges_[0] = Type::Signed32();
-  if (SmiValuesAre31Bits()) {
-    shifted_int32_ranges_[1] = Type::SignedSmall();
-    for (size_t k = 2; k < arraysize(shifted_int32_ranges_); ++k) {
-      double min = kMinInt / (1 << k);
-      double max = kMaxInt / (1 << k);
-      shifted_int32_ranges_[k] = Type::Range(min, max, graph()->zone());
-    }
-  } else {
-    for (size_t k = 1; k < arraysize(shifted_int32_ranges_); ++k) {
-      double min = kMinInt / (1 << k);
-      double max = kMaxInt / (1 << k);
-      shifted_int32_ranges_[k] = Type::Range(min, max, graph()->zone());
-    }
+  for (size_t k = 0; k < arraysize(shifted_int32_ranges_); ++k) {
+    double min = kMinInt / (1 << k);
+    double max = kMaxInt / (1 << k);
+    shifted_int32_ranges_[k] = Type::Range(min, max, graph()->zone());
   }
 }
 
 
 Reduction JSTypedLowering::ReplaceEagerly(Node* old, Node* node) {
   NodeProperties::ReplaceWithValue(old, node, node);
   return Changed(node);
 }
 
 
@@ skipping 960 matching lines @@
 }
 
 
 MachineOperatorBuilder* JSTypedLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8