From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Georg Neis <neis@chromium.org>
Date: Wed, 14 Apr 2021 13:19:44 +0200
Subject: Merged: [compiler] Fix bug in
 RepresentationChanger::GetWord32RepresentationFor

Revision: fd29e246f65a7cee130e72cd10f618f3b82af232

BUG=chromium:1195777
NOTRY=true
NOPRESUBMIT=true
NOTREECHECKS=true
R=nicohartmann@chromium.org

Change-Id: I0400b3ae5736ef86dbeae558d15bfcca2e9f351a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2826114
Commit-Queue: Georg Neis <neis@chromium.org>
Reviewed-by: Nico Hartmann <nicohartmann@chromium.org>
Cr-Commit-Position: refs/branch-heads/9.0@{#34}
Cr-Branched-From: bd0108b4c88e0d6f2350cb79b5f363fbd02f3eb7-refs/heads/9.0.257@{#1}
Cr-Branched-From: 349bcc6a075411f1a7ce2d866c3dfeefc2efa39d-refs/heads/master@{#73001}

diff --git a/src/compiler/representation-change.cc b/src/compiler/representation-change.cc
index 2455ea31157269e2ed19eb880818dc08aa7a508f..4fd8be432e30fc98802ba37d64f28613968226b6 100644
--- a/src/compiler/representation-change.cc
+++ b/src/compiler/representation-change.cc
@@ -949,10 +949,10 @@ Node* RepresentationChanger::GetWord32RepresentationFor(
     return node;
   } else if (output_rep == MachineRepresentation::kWord64) {
     if (output_type.Is(Type::Signed32()) ||
-        output_type.Is(Type::Unsigned32())) {
-      op = machine()->TruncateInt64ToInt32();
-    } else if (output_type.Is(cache_->kSafeInteger) &&
-               use_info.truncation().IsUsedAsWord32()) {
+        (output_type.Is(Type::Unsigned32()) &&
+         use_info.type_check() == TypeCheckKind::kNone) ||
+        (output_type.Is(cache_->kSafeInteger) &&
+         use_info.truncation().IsUsedAsWord32())) {
       op = machine()->TruncateInt64ToInt32();
     } else if (use_info.type_check() == TypeCheckKind::kSignedSmall ||
                use_info.type_check() == TypeCheckKind::kSigned32 ||
diff --git a/test/mjsunit/compiler/regress-1195777.js b/test/mjsunit/compiler/regress-1195777.js
new file mode 100644
index 0000000000000000000000000000000000000000..b122f4f0169af573723d4318b9f1127c857c9e35
--- /dev/null
+++ b/test/mjsunit/compiler/regress-1195777.js
@@ -0,0 +1,62 @@
+// 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() {
+  function foo(b) {
+    let y = (new Date(42)).getMilliseconds();
+    let x = -1;
+    if (b) x = 0xFFFF_FFFF;
+    return y < Math.max(1 << y, x, 1 + y);
+  }
+  assertTrue(foo(true));
+  %PrepareFunctionForOptimization(foo);
+  assertTrue(foo(false));
+  %OptimizeFunctionOnNextCall(foo);
+  assertTrue(foo(true));
+})();
+
+
+(function() {
+  function foo(b) {
+    let x = 0;
+    if (b) x = -1;
+    return x == Math.max(-1, x >>> Infinity);
+  }
+  assertFalse(foo(true));
+  %PrepareFunctionForOptimization(foo);
+  assertTrue(foo(false));
+  %OptimizeFunctionOnNextCall(foo);
+  assertFalse(foo(true));
+})();
+
+
+(function() {
+  function foo(b) {
+    let x = -1;
+    if (b) x = 0xFFFF_FFFF;
+    return -1 < Math.max(0, x, -1);
+  }
+  assertTrue(foo(true));
+  %PrepareFunctionForOptimization(foo);
+  assertTrue(foo(false));
+  %OptimizeFunctionOnNextCall(foo);
+  assertTrue(foo(true));
+})();
+
+
+(function() {
+  function foo(b) {
+    let x = 0x7FFF_FFFF;
+    if (b) x = 0;
+    return 0 < (Math.max(-5 >>> x, -5) % -5);
+  }
+  assertTrue(foo(true));
+  %PrepareFunctionForOptimization(foo);
+  assertTrue(foo(false));
+  %OptimizeFunctionOnNextCall(foo);
+  assertTrue(foo(true));
+})();