From 2923136f95c2504716440b8e4401939109ab239f Mon Sep 17 00:00:00 2001
From: "yangguo@chromium.org"
 <yangguo@chromium.org@ce2b1a6d-e550-0410-aec6-3dcde31c8c00>
Date: Thu, 27 Oct 2011 07:59:12 +0000
Subject: [PATCH] Fixing performance regression in issue 1787.

BUG=v8:1787

Review URL: http://codereview.chromium.org/8390050

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9812 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
---
 src/arm/code-stubs-arm.cc   | 15 +++++++++++++--
 src/ia32/code-stubs-ia32.cc |  5 +++++
 src/x64/code-stubs-x64.cc   |  5 +++++
 3 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/src/arm/code-stubs-arm.cc b/src/arm/code-stubs-arm.cc
index 412ba00fc..cb3bc88a7 100644
--- a/src/arm/code-stubs-arm.cc
+++ b/src/arm/code-stubs-arm.cc
@@ -6839,6 +6839,11 @@ void StringDictionaryLookupStub::GeneratePositiveLookup(MacroAssembler* masm,
                                                         Register name,
                                                         Register scratch1,
                                                         Register scratch2) {
+  ASSERT(!elements.is(scratch1));
+  ASSERT(!elements.is(scratch2));
+  ASSERT(!name.is(scratch1));
+  ASSERT(!name.is(scratch2));
+
   // Assert that name contains a string.
   if (FLAG_debug_code) __ AbortIfNotString(name);
 
@@ -6882,8 +6887,14 @@ void StringDictionaryLookupStub::GeneratePositiveLookup(MacroAssembler* masm,
       ~(scratch1.bit() | scratch2.bit());
 
   __ stm(db_w, sp, spill_mask);
-  __ Move(r0, elements);
-  __ Move(r1, name);
+  if (name.is(r0)) {
+    ASSERT(!elements.is(r1));
+    __ Move(r1, name);
+    __ Move(r0, elements);
+  } else {
+    __ Move(r0, elements);
+    __ Move(r1, name);
+  }
   StringDictionaryLookupStub stub(POSITIVE_LOOKUP);
   __ CallStub(&stub);
   __ tst(r0, Operand(r0));
diff --git a/src/ia32/code-stubs-ia32.cc b/src/ia32/code-stubs-ia32.cc
index d7d1d9c3c..37b519aad 100644
--- a/src/ia32/code-stubs-ia32.cc
+++ b/src/ia32/code-stubs-ia32.cc
@@ -6673,6 +6673,11 @@ void StringDictionaryLookupStub::GeneratePositiveLookup(MacroAssembler* masm,
                                                         Register name,
                                                         Register r0,
                                                         Register r1) {
+  ASSERT(!elements.is(r0));
+  ASSERT(!elements.is(r1));
+  ASSERT(!name.is(r0));
+  ASSERT(!name.is(r1));
+
   // Assert that name contains a string.
   if (FLAG_debug_code) __ AbortIfNotString(name);
 
diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index 3dfebeec4..f62c5172e 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -5595,6 +5595,11 @@ void StringDictionaryLookupStub::GeneratePositiveLookup(MacroAssembler* masm,
                                                         Register name,
                                                         Register r0,
                                                         Register r1) {
+  ASSERT(!elements.is(r0));
+  ASSERT(!elements.is(r1));
+  ASSERT(!name.is(r0));
+  ASSERT(!name.is(r1));
+
   // Assert that name contains a string.
   if (FLAG_debug_code) __ AbortIfNotString(name);
 
-- 
2.34.1