From: jkummerow <jkummerow@chromium.org>
Date: Wed, 8 Jul 2015 10:20:23 +0000 (-0700)
Subject: [x64] Fix handling of Smi constants in LSubI and LBitI
X-Git-Tag: upstream/4.7.83~1511
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=5379d8bc36b3388df4f5a6f7e0a86168f1a5ff0e;p=platform%2Fupstream%2Fv8.git

[x64] Fix handling of Smi constants in LSubI and LBitI

Smi immediates are not supported, so instructions with Smi representations need their constants in a register. LAddI has already been doing this. The manifestation of the bug was that an operation would compute 0 instead of the correct result.

BUG=chromium:478612
LOG=y
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/1224623017

Cr-Commit-Position: refs/heads/master@{#29529}
---

diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index 8f3750552..3c150e21c 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1307,7 +1307,13 @@ LInstruction* LChunkBuilder::DoBitwise(HBitwise* instr) {
     DCHECK(instr->CheckFlag(HValue::kTruncatingToInt32));
 
     LOperand* left = UseRegisterAtStart(instr->BetterLeftOperand());
-    LOperand* right = UseOrConstantAtStart(instr->BetterRightOperand());
+    LOperand* right;
+    if (SmiValuesAre32Bits() && instr->representation().IsSmi()) {
+      // We don't support tagged immediates, so we request it in a register.
+      right = UseRegisterAtStart(instr->BetterRightOperand());
+    } else {
+      right = UseOrConstantAtStart(instr->BetterRightOperand());
+    }
     return DefineSameAsFirst(new(zone()) LBitI(left, right));
   } else {
     return DoArithmeticT(instr->op(), instr);
@@ -1549,7 +1555,13 @@ LInstruction* LChunkBuilder::DoSub(HSub* instr) {
     DCHECK(instr->left()->representation().Equals(instr->representation()));
     DCHECK(instr->right()->representation().Equals(instr->representation()));
     LOperand* left = UseRegisterAtStart(instr->left());
-    LOperand* right = UseOrConstantAtStart(instr->right());
+    LOperand* right;
+    if (SmiValuesAre32Bits() && instr->representation().IsSmi()) {
+      // We don't support tagged immediates, so we request it in a register.
+      right = UseRegisterAtStart(instr->right());
+    } else {
+      right = UseOrConstantAtStart(instr->right());
+    }
     LSubI* sub = new(zone()) LSubI(left, right);
     LInstruction* result = DefineSameAsFirst(sub);
     if (instr->CheckFlag(HValue::kCanOverflow)) {
diff --git a/test/mjsunit/regress/regress-crbug-478612.js b/test/mjsunit/regress/regress-crbug-478612.js
new file mode 100644
index 000000000..3419722cd
--- /dev/null
+++ b/test/mjsunit/regress/regress-crbug-478612.js
@@ -0,0 +1,52 @@
+// Copyright 2015 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
+
+// This is used to force binary operations below to have tagged representation.
+var z = {valueOf: function() { return 3; }};
+
+
+function f() {
+  var y = -2;
+  return (1 & z) - y++;
+}
+
+assertEquals(3, f());
+assertEquals(3, f());
+%OptimizeFunctionOnNextCall(f);
+assertEquals(3, f());
+
+
+function g() {
+  var y = 2;
+  return (1 & z) | y++;
+}
+
+assertEquals(3, g());
+assertEquals(3, g());
+%OptimizeFunctionOnNextCall(g);
+assertEquals(3, g());
+
+
+function h() {
+  var y = 3;
+  return (3 & z) & y++;
+}
+
+assertEquals(3, h());
+assertEquals(3, h());
+%OptimizeFunctionOnNextCall(h);
+assertEquals(3, h());
+
+
+function i() {
+  var y = 2;
+  return (1 & z) ^ y++;
+}
+
+assertEquals(3, i());
+assertEquals(3, i());
+%OptimizeFunctionOnNextCall(i);
+assertEquals(3, i());