[ptr-compr] Adding compressed case to lowering of Boolean Not

Fixes the chromium bug 963891

Bug: chromium:963891
Change-Id: Ie90c9581044b7d10dd8fcd73d52bda5fdfead292
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1617248Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61608}

src/compiler/simplified-lowering.cc

@@ -1745,6 +1745,10 @@ class RepresentationSelector {
             // BooleanNot(x: kRepTagged) => WordEqual(x, #false)
             node->AppendInput(jsgraph_->zone(), jsgraph_->FalseConstant());
             NodeProperties::ChangeOp(node, lowering->machine()->WordEqual());
+          } else if (CanBeCompressedPointer(input_info->representation())) {
+            // BooleanNot(x: kRepCompressed) => Word32Equal(x, #false)
+            node->AppendInput(jsgraph_->zone(), jsgraph_->FalseConstant());
+            NodeProperties::ChangeOp(node, lowering->machine()->Word32Equal());
           } else {
             DCHECK(TypeOf(node->InputAt(0)).IsNone());
             DeferReplacement(node, lowering->jsgraph()->Int32Constant(0));

test/mjsunit/regress/regress-963891.js

+// Copyright 2019 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.
+
+// Flags: --allow-natives-syntax
+
+var bar = true;
+bar = false;
+function foo() {
+  return !bar;
+}
+assertEquals(foo(), true);
+%OptimizeFunctionOnNextCall(foo);
+assertEquals(foo(), true);