deps: V8: cherry-pick 3066b7b2fcb3

Original commit message:

    [LTS-M86][compiler][x64] Fix bug in InstructionSelector::ChangeInt32ToInt64

    (cherry picked from commit 02f84c745fc0cae5927a66dc4a3e81334e8f60a6)

    No-Try: true
    No-Presubmit: true
    No-Tree-Checks: true
    Bug: chromium:1196683
    Change-Id: Ib4ea738b47b64edc81450583be4c80a41698c3d1
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2820971
    Commit-Queue: Georg Neis <[email protected]>
    Reviewed-by: Nico Hartmann <[email protected]>
    Cr-Original-Commit-Position: refs/heads/master@{#73903}
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2821959
    Commit-Queue: Jana Grill <[email protected]>
    Reviewed-by: Georg Neis <[email protected]>
    Reviewed-by: Victor-Gabriel Savu <[email protected]>
    Cr-Commit-Position: refs/branch-heads/8.6@{nodejs#75}
    Cr-Branched-From: a64aed2333abf49e494d2a5ce24bbd14fff19f60-refs/heads/8.6.395@{#1}
    Cr-Branched-From: a626bc036236c9bf92ac7b87dc40c9e538b087e3-refs/heads/master@{#69472}

Refs: v8/v8@3066b7b

common.gypi

@@ -36,7 +36,7 @@
 
     # Reset this number to 0 on major V8 upgrades.
     # Increment by one for each non-official patch applied to deps/v8.
-    'v8_embedder_string': '-node.49',
+    'v8_embedder_string': '-node.50',
 
     ##### V8 defaults for Node.js #####
 

deps/v8/src/compiler/backend/x64/instruction-selector-x64.cc

@@ -1270,7 +1270,9 @@ void InstructionSelector::VisitChangeInt32ToInt64(Node* node) {
         opcode = load_rep.IsSigned() ? kX64Movsxwq : kX64Movzxwq;
         break;
       case MachineRepresentation::kWord32:
-        opcode = load_rep.IsSigned() ? kX64Movsxlq : kX64Movl;
+        // ChangeInt32ToInt64 must interpret its input as a _signed_ 32-bit
+        // integer, so here we must sign-extend the loaded value in any case.
+        opcode = kX64Movsxlq;
         break;
       default:
         UNREACHABLE();

deps/v8/test/mjsunit/compiler/regress-1196683.js

@@ -0,0 +1,56 @@
+// Copyright 2021 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
+
+
+(function() {
+  const arr = new Uint32Array([2**31]);
+  function foo() {
+    return (arr[0] ^ 0) + 1;
+  }
+  %PrepareFunctionForOptimization(foo);
+  assertEquals(-(2**31) + 1, foo());
+  %OptimizeFunctionOnNextCall(foo);
+  assertEquals(-(2**31) + 1, foo());
+});
+
+
+// The remaining tests already passed without the bugfix.
+
+
+(function() {
+  const arr = new Uint16Array([2**15]);
+  function foo() {
+    return (arr[0] ^ 0) + 1;
+  }
+  %PrepareFunctionForOptimization(foo);
+  assertEquals(2**15 + 1, foo());
+  %OptimizeFunctionOnNextCall(foo);
+  assertEquals(2**15 + 1, foo());
+})();
+
+
+(function() {
+  const arr = new Uint8Array([2**7]);
+  function foo() {
+    return (arr[0] ^ 0) + 1;
+  }
+  %PrepareFunctionForOptimization(foo);
+  assertEquals(2**7 + 1, foo());
+  %OptimizeFunctionOnNextCall(foo);
+  assertEquals(2**7 + 1, foo());
+})();
+
+
+(function() {
+  const arr = new Int32Array([-(2**31)]);
+  function foo() {
+    return (arr[0] >>> 0) + 1;
+  }
+  %PrepareFunctionForOptimization(foo);
+  assertEquals(2**31 + 1, foo());
+  %OptimizeFunctionOnNextCall(foo);
+  assertEquals(2**31 + 1, foo());
+})();