[turbofan] Get rid of truncation by store.

test/unittests/compiler/js-typed-lowering-unittest.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/code-factory.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-operator.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/machine-operator.h"
@@ skipping 764 matching lines @@
       Reduction r = Reduce(node);
 
       Matcher<Node*> offset_matcher =
           element_size == 1
               ? key
               : IsWord32Shl(key, IsInt32Constant(WhichPowerOf2(element_size)));
 
       Matcher<Node*> value_matcher =
           IsToNumber(value, context, effect, control);
       Matcher<Node*> effect_matcher = value_matcher;
-      if (AccessBuilder::ForTypedArrayElement(type, true)
-              .type->Is(Type::Signed32())) {
-        value_matcher = IsNumberToInt32(value_matcher);
-      } else if (AccessBuilder::ForTypedArrayElement(type, true)
-                     .type->Is(Type::Unsigned32())) {
-        value_matcher = IsNumberToUint32(value_matcher);
-      }
 
       ASSERT_TRUE(r.Changed());
       EXPECT_THAT(
           r.replacement(),
           IsStoreBuffer(BufferAccess(type),
                         IsIntPtrConstant(bit_cast<intptr_t>(&backing_store[0])),
                         offset_matcher,
                         IsNumberConstant(array->byte_length()->Number()),
                         value_matcher, effect_matcher, control));
     }
@@ skipping 418 matching lines @@
   Node* dummy = graph()->NewNode(javascript()->ToObject(), instanceOf, context,
                                  frame_state, effect, control);
   Reduction r = Reduce(instanceOf);
   ASSERT_FALSE(r.Changed());
   ASSERT_EQ(instanceOf, dummy->InputAt(0));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8