Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4 (http://svn.webkit.org/repository/webkit/trunk@104285)

1 files changed, 1139 insertions, 0 deletions

diff --git a/Source/JavaScriptCore/jit/JITArithmetic.cpp b/Source/JavaScriptCore/jit/JITArithmetic.cpp
new file mode 100644
index 000000000..362cc6241
--- /dev/null
+++ b/Source/JavaScriptCore/jit/JITArithmetic.cpp
@@ -0,0 +1,1139 @@
+/*
+ * Copyright (C) 2008 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#if ENABLE(JIT)
+#include "JIT.h"
+
+#include "CodeBlock.h"
+#include "JITInlineMethods.h"
+#include "JITStubCall.h"
+#include "JITStubs.h"
+#include "JSArray.h"
+#include "JSFunction.h"
+#include "Interpreter.h"
+#include "ResultType.h"
+#include "SamplingTool.h"
+
+#ifndef NDEBUG
+#include <stdio.h>
+#endif
+
+using namespace std;
+
+namespace JSC {
+
+void JIT::emit_op_jless(Instruction* currentInstruction)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJump(op_jless, op1, op2, target, LessThan);
+}
+
+void JIT::emit_op_jlesseq(Instruction* currentInstruction)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJump(op_jlesseq, op1, op2, target, LessThanOrEqual);
+}
+
+void JIT::emit_op_jgreater(Instruction* currentInstruction)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJump(op_jgreater, op1, op2, target, GreaterThan);
+}
+
+void JIT::emit_op_jgreatereq(Instruction* currentInstruction)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJump(op_jgreatereq, op1, op2, target, GreaterThanOrEqual);
+}
+
+void JIT::emit_op_jnless(Instruction* currentInstruction)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJump(op_jnless, op1, op2, target, GreaterThanOrEqual);
+}
+
+void JIT::emit_op_jnlesseq(Instruction* currentInstruction)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJump(op_jnlesseq, op1, op2, target, GreaterThan);
+}
+
+void JIT::emit_op_jngreater(Instruction* currentInstruction)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJump(op_jngreater, op1, op2, target, LessThanOrEqual);
+}
+
+void JIT::emit_op_jngreatereq(Instruction* currentInstruction)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJump(op_jngreatereq, op1, op2, target, LessThan);
+}
+
+void JIT::emitSlow_op_jless(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJumpSlow(op1, op2, target, DoubleLessThan, cti_op_jless, false, iter);
+}
+
+void JIT::emitSlow_op_jlesseq(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJumpSlow(op1, op2, target, DoubleLessThanOrEqual, cti_op_jlesseq, false, iter);
+}
+
+void JIT::emitSlow_op_jgreater(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJumpSlow(op1, op2, target, DoubleGreaterThan, cti_op_jgreater, false, iter);
+}
+
+void JIT::emitSlow_op_jgreatereq(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJumpSlow(op1, op2, target, DoubleGreaterThanOrEqual, cti_op_jgreatereq, false, iter);
+}
+
+void JIT::emitSlow_op_jnless(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJumpSlow(op1, op2, target, DoubleGreaterThanOrEqualOrUnordered, cti_op_jless, true, iter);
+}
+
+void JIT::emitSlow_op_jnlesseq(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJumpSlow(op1, op2, target, DoubleGreaterThanOrUnordered, cti_op_jlesseq, true, iter);
+}
+
+void JIT::emitSlow_op_jngreater(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJumpSlow(op1, op2, target, DoubleLessThanOrEqualOrUnordered, cti_op_jgreater, true, iter);
+}
+
+void JIT::emitSlow_op_jngreatereq(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned op1 = currentInstruction[1].u.operand;
+    unsigned op2 = currentInstruction[2].u.operand;
+    unsigned target = currentInstruction[3].u.operand;
+
+    emit_compareAndJumpSlow(op1, op2, target, DoubleLessThanOrUnordered, cti_op_jgreatereq, true, iter);
+}
+
+#if USE(JSVALUE64)
+
+void JIT::emit_op_lshift(Instruction* currentInstruction)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+
+    emitGetVirtualRegisters(op1, regT0, op2, regT2);
+    // FIXME: would we be better using 'emitJumpSlowCaseIfNotImmediateIntegers'? - we *probably* ought to be consistent.
+    emitJumpSlowCaseIfNotImmediateInteger(regT0);
+    emitJumpSlowCaseIfNotImmediateInteger(regT2);
+    emitFastArithImmToInt(regT0);
+    emitFastArithImmToInt(regT2);
+    lshift32(regT2, regT0);
+    emitFastArithReTagImmediate(regT0, regT0);
+    emitPutVirtualRegister(result);
+}
+
+void JIT::emitSlow_op_lshift(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+
+    UNUSED_PARAM(op1);
+    UNUSED_PARAM(op2);
+    linkSlowCase(iter);
+    linkSlowCase(iter);
+    JITStubCall stubCall(this, cti_op_lshift);
+    stubCall.addArgument(regT0);
+    stubCall.addArgument(regT2);
+    stubCall.call(result);
+}
+
+void JIT::emit_op_rshift(Instruction* currentInstruction)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+
+    if (isOperandConstantImmediateInt(op2)) {
+        // isOperandConstantImmediateInt(op2) => 1 SlowCase
+        emitGetVirtualRegister(op1, regT0);
+        emitJumpSlowCaseIfNotImmediateInteger(regT0);
+        // Mask with 0x1f as per ecma-262 11.7.2 step 7.
+        rshift32(Imm32(getConstantOperandImmediateInt(op2) & 0x1f), regT0);
+    } else {
+        emitGetVirtualRegisters(op1, regT0, op2, regT2);
+        if (supportsFloatingPointTruncate()) {
+            Jump lhsIsInt = emitJumpIfImmediateInteger(regT0);
+            // supportsFloatingPoint() && USE(JSVALUE64) => 3 SlowCases
+            addSlowCase(emitJumpIfNotImmediateNumber(regT0));
+            addPtr(tagTypeNumberRegister, regT0);
+            movePtrToDouble(regT0, fpRegT0);
+            addSlowCase(branchTruncateDoubleToInt32(fpRegT0, regT0));
+            lhsIsInt.link(this);
+            emitJumpSlowCaseIfNotImmediateInteger(regT2);
+        } else {
+            // !supportsFloatingPoint() => 2 SlowCases
+            emitJumpSlowCaseIfNotImmediateInteger(regT0);
+            emitJumpSlowCaseIfNotImmediateInteger(regT2);
+        }
+        emitFastArithImmToInt(regT2);
+        rshift32(regT2, regT0);
+    }
+    emitFastArithIntToImmNoCheck(regT0, regT0);
+    emitPutVirtualRegister(result);
+}
+
+void JIT::emitSlow_op_rshift(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+
+    JITStubCall stubCall(this, cti_op_rshift);
+
+    if (isOperandConstantImmediateInt(op2)) {
+        linkSlowCase(iter);
+        stubCall.addArgument(regT0);
+        stubCall.addArgument(op2, regT2);
+    } else {
+        if (supportsFloatingPointTruncate()) {
+            linkSlowCase(iter);
+            linkSlowCase(iter);
+            linkSlowCase(iter);
+            // We're reloading op1 to regT0 as we can no longer guarantee that
+            // we have not munged the operand.  It may have already been shifted
+            // correctly, but it still will not have been tagged.
+            stubCall.addArgument(op1, regT0);
+            stubCall.addArgument(regT2);
+        } else {
+            linkSlowCase(iter);
+            linkSlowCase(iter);
+            stubCall.addArgument(regT0);
+            stubCall.addArgument(regT2);
+        }
+    }
+
+    stubCall.call(result);
+}
+
+void JIT::emit_op_urshift(Instruction* currentInstruction)
+{
+    unsigned dst = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+
+    // Slow case of urshift makes assumptions about what registers hold the
+    // shift arguments, so any changes must be updated there as well.
+    if (isOperandConstantImmediateInt(op2)) {
+        emitGetVirtualRegister(op1, regT0);
+        emitJumpSlowCaseIfNotImmediateInteger(regT0);
+        emitFastArithImmToInt(regT0);
+        int shift = getConstantOperand(op2).asInt32();
+        if (shift)
+            urshift32(Imm32(shift & 0x1f), regT0);
+        // unsigned shift < 0 or shift = k*2^32 may result in (essentially)
+        // a toUint conversion, which can result in a value we can represent
+        // as an immediate int.
+        if (shift < 0 || !(shift & 31))
+            addSlowCase(branch32(LessThan, regT0, TrustedImm32(0)));
+        emitFastArithReTagImmediate(regT0, regT0);
+        emitPutVirtualRegister(dst, regT0);
+        return;
+    }
+    emitGetVirtualRegisters(op1, regT0, op2, regT1);
+    if (!isOperandConstantImmediateInt(op1))
+        emitJumpSlowCaseIfNotImmediateInteger(regT0);
+    emitJumpSlowCaseIfNotImmediateInteger(regT1);
+    emitFastArithImmToInt(regT0);
+    emitFastArithImmToInt(regT1);
+    urshift32(regT1, regT0);
+    addSlowCase(branch32(LessThan, regT0, TrustedImm32(0)));
+    emitFastArithReTagImmediate(regT0, regT0);
+    emitPutVirtualRegister(dst, regT0);
+}
+
+void JIT::emitSlow_op_urshift(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned dst = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+    if (isOperandConstantImmediateInt(op2)) {
+        int shift = getConstantOperand(op2).asInt32();
+        // op1 = regT0
+        linkSlowCase(iter); // int32 check
+        if (supportsFloatingPointTruncate()) {
+            JumpList failures;
+            failures.append(emitJumpIfNotImmediateNumber(regT0)); // op1 is not a double
+            addPtr(tagTypeNumberRegister, regT0);
+            movePtrToDouble(regT0, fpRegT0);
+            failures.append(branchTruncateDoubleToInt32(fpRegT0, regT0));
+            if (shift)
+                urshift32(Imm32(shift & 0x1f), regT0);
+            if (shift < 0 || !(shift & 31))
+                failures.append(branch32(LessThan, regT0, TrustedImm32(0)));
+            emitFastArithReTagImmediate(regT0, regT0);
+            emitPutVirtualRegister(dst, regT0);
+            emitJumpSlowToHot(jump(), OPCODE_LENGTH(op_rshift));
+            failures.link(this);
+        }
+        if (shift < 0 || !(shift & 31))
+            linkSlowCase(iter); // failed to box in hot path
+    } else {
+        // op1 = regT0
+        // op2 = regT1
+        if (!isOperandConstantImmediateInt(op1)) {
+            linkSlowCase(iter); // int32 check -- op1 is not an int
+            if (supportsFloatingPointTruncate()) {
+                JumpList failures;
+                failures.append(emitJumpIfNotImmediateNumber(regT0)); // op1 is not a double
+                addPtr(tagTypeNumberRegister, regT0);
+                movePtrToDouble(regT0, fpRegT0);
+                failures.append(branchTruncateDoubleToInt32(fpRegT0, regT0));
+                failures.append(emitJumpIfNotImmediateInteger(regT1)); // op2 is not an int
+                emitFastArithImmToInt(regT1);
+                urshift32(regT1, regT0);
+                failures.append(branch32(LessThan, regT0, TrustedImm32(0)));
+                emitFastArithReTagImmediate(regT0, regT0);
+                emitPutVirtualRegister(dst, regT0);
+                emitJumpSlowToHot(jump(), OPCODE_LENGTH(op_rshift));
+                failures.link(this);
+            }
+        }
+        
+        linkSlowCase(iter); // int32 check - op2 is not an int
+        linkSlowCase(iter); // Can't represent unsigned result as an immediate
+    }
+    
+    JITStubCall stubCall(this, cti_op_urshift);
+    stubCall.addArgument(op1, regT0);
+    stubCall.addArgument(op2, regT1);
+    stubCall.call(dst);
+}
+
+void JIT::emit_compareAndJump(OpcodeID, unsigned op1, unsigned op2, unsigned target, RelationalCondition condition)
+{
+    // We generate inline code for the following cases in the fast path:
+    // - int immediate to constant int immediate
+    // - constant int immediate to int immediate
+    // - int immediate to int immediate
+
+    if (isOperandConstantImmediateChar(op1)) {
+        emitGetVirtualRegister(op2, regT0);
+        addSlowCase(emitJumpIfNotJSCell(regT0));
+        JumpList failures;
+        emitLoadCharacterString(regT0, regT0, failures);
+        addSlowCase(failures);
+        addJump(branch32(commute(condition), regT0, Imm32(asString(getConstantOperand(op1))->tryGetValue()[0])), target);
+        return;
+    }
+    if (isOperandConstantImmediateChar(op2)) {
+        emitGetVirtualRegister(op1, regT0);
+        addSlowCase(emitJumpIfNotJSCell(regT0));
+        JumpList failures;
+        emitLoadCharacterString(regT0, regT0, failures);
+        addSlowCase(failures);
+        addJump(branch32(condition, regT0, Imm32(asString(getConstantOperand(op2))->tryGetValue()[0])), target);
+        return;
+    }
+    if (isOperandConstantImmediateInt(op2)) {
+        emitGetVirtualRegister(op1, regT0);
+        emitJumpSlowCaseIfNotImmediateInteger(regT0);
+        int32_t op2imm = getConstantOperandImmediateInt(op2);
+        addJump(branch32(condition, regT0, Imm32(op2imm)), target);
+    } else if (isOperandConstantImmediateInt(op1)) {
+        emitGetVirtualRegister(op2, regT1);
+        emitJumpSlowCaseIfNotImmediateInteger(regT1);
+        int32_t op1imm = getConstantOperandImmediateInt(op1);
+        addJump(branch32(commute(condition), regT1, Imm32(op1imm)), target);
+    } else {
+        emitGetVirtualRegisters(op1, regT0, op2, regT1);
+        emitJumpSlowCaseIfNotImmediateInteger(regT0);
+        emitJumpSlowCaseIfNotImmediateInteger(regT1);
+
+        addJump(branch32(condition, regT0, regT1), target);
+    }
+}
+
+void JIT::emit_compareAndJumpSlow(unsigned op1, unsigned op2, unsigned target, DoubleCondition condition, int (JIT_STUB *stub)(STUB_ARGS_DECLARATION), bool invert, Vector<SlowCaseEntry>::iterator& iter)
+{
+    COMPILE_ASSERT(OPCODE_LENGTH(op_jless) == OPCODE_LENGTH(op_jlesseq), OPCODE_LENGTH_op_jlesseq_equals_op_jless);
+    COMPILE_ASSERT(OPCODE_LENGTH(op_jless) == OPCODE_LENGTH(op_jnless), OPCODE_LENGTH_op_jnless_equals_op_jless);
+    COMPILE_ASSERT(OPCODE_LENGTH(op_jless) == OPCODE_LENGTH(op_jnlesseq), OPCODE_LENGTH_op_jnlesseq_equals_op_jless);
+    COMPILE_ASSERT(OPCODE_LENGTH(op_jless) == OPCODE_LENGTH(op_jgreater), OPCODE_LENGTH_op_jgreater_equals_op_jless);
+    COMPILE_ASSERT(OPCODE_LENGTH(op_jless) == OPCODE_LENGTH(op_jgreatereq), OPCODE_LENGTH_op_jgreatereq_equals_op_jless);
+    COMPILE_ASSERT(OPCODE_LENGTH(op_jless) == OPCODE_LENGTH(op_jngreater), OPCODE_LENGTH_op_jngreater_equals_op_jless);
+    COMPILE_ASSERT(OPCODE_LENGTH(op_jless) == OPCODE_LENGTH(op_jngreatereq), OPCODE_LENGTH_op_jngreatereq_equals_op_jless);
+    
+    // We generate inline code for the following cases in the slow path:
+    // - floating-point number to constant int immediate
+    // - constant int immediate to floating-point number
+    // - floating-point number to floating-point number.
+    if (isOperandConstantImmediateChar(op1) || isOperandConstantImmediateChar(op2)) {
+        linkSlowCase(iter);
+        linkSlowCase(iter);
+        linkSlowCase(iter);
+        linkSlowCase(iter);
+        JITStubCall stubCall(this, stub);
+        stubCall.addArgument(op1, regT0);
+        stubCall.addArgument(op2, regT1);
+        stubCall.call();
+        emitJumpSlowToHot(branchTest32(invert ? Zero : NonZero, regT0), target);
+        return;
+    }
+
+    if (isOperandConstantImmediateInt(op2)) {
+        linkSlowCase(iter);
+
+        if (supportsFloatingPoint()) {
+            Jump fail1 = emitJumpIfNotImmediateNumber(regT0);
+            addPtr(tagTypeNumberRegister, regT0);
+            movePtrToDouble(regT0, fpRegT0);
+
+            int32_t op2imm = getConstantOperand(op2).asInt32();
+
+            move(Imm32(op2imm), regT1);
+            convertInt32ToDouble(regT1, fpRegT1);
+
+            emitJumpSlowToHot(branchDouble(condition, fpRegT0, fpRegT1), target);
+
+            emitJumpSlowToHot(jump(), OPCODE_LENGTH(op_jless));
+
+            fail1.link(this);
+        }
+
+        JITStubCall stubCall(this, stub);
+        stubCall.addArgument(regT0);
+        stubCall.addArgument(op2, regT2);
+        stubCall.call();
+        emitJumpSlowToHot(branchTest32(invert ? Zero : NonZero, regT0), target);
+
+    } else if (isOperandConstantImmediateInt(op1)) {
+        linkSlowCase(iter);
+
+        if (supportsFloatingPoint()) {
+            Jump fail1 = emitJumpIfNotImmediateNumber(regT1);
+            addPtr(tagTypeNumberRegister, regT1);
+            movePtrToDouble(regT1, fpRegT1);
+
+            int32_t op1imm = getConstantOperand(op1).asInt32();
+
+            move(Imm32(op1imm), regT0);
+            convertInt32ToDouble(regT0, fpRegT0);
+
+            emitJumpSlowToHot(branchDouble(condition, fpRegT0, fpRegT1), target);
+
+            emitJumpSlowToHot(jump(), OPCODE_LENGTH(op_jless));
+
+            fail1.link(this);
+        }
+
+        JITStubCall stubCall(this, stub);
+        stubCall.addArgument(op1, regT2);
+        stubCall.addArgument(regT1);
+        stubCall.call();
+        emitJumpSlowToHot(branchTest32(invert ? Zero : NonZero, regT0), target);
+    } else {
+        linkSlowCase(iter);
+
+        if (supportsFloatingPoint()) {
+            Jump fail1 = emitJumpIfNotImmediateNumber(regT0);
+            Jump fail2 = emitJumpIfNotImmediateNumber(regT1);
+            Jump fail3 = emitJumpIfImmediateInteger(regT1);
+            addPtr(tagTypeNumberRegister, regT0);
+            addPtr(tagTypeNumberRegister, regT1);
+            movePtrToDouble(regT0, fpRegT0);
+            movePtrToDouble(regT1, fpRegT1);
+
+            emitJumpSlowToHot(branchDouble(condition, fpRegT0, fpRegT1), target);
+
+            emitJumpSlowToHot(jump(), OPCODE_LENGTH(op_jless));
+
+            fail1.link(this);
+            fail2.link(this);
+            fail3.link(this);
+        }
+
+        linkSlowCase(iter);
+        JITStubCall stubCall(this, stub);
+        stubCall.addArgument(regT0);
+        stubCall.addArgument(regT1);
+        stubCall.call();
+        emitJumpSlowToHot(branchTest32(invert ? Zero : NonZero, regT0), target);
+    }
+}
+
+void JIT::emit_op_bitand(Instruction* currentInstruction)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+
+    if (isOperandConstantImmediateInt(op1)) {
+        emitGetVirtualRegister(op2, regT0);
+        emitJumpSlowCaseIfNotImmediateInteger(regT0);
+        int32_t imm = getConstantOperandImmediateInt(op1);
+        andPtr(Imm32(imm), regT0);
+        if (imm >= 0)
+            emitFastArithIntToImmNoCheck(regT0, regT0);
+    } else if (isOperandConstantImmediateInt(op2)) {
+        emitGetVirtualRegister(op1, regT0);
+        emitJumpSlowCaseIfNotImmediateInteger(regT0);
+        int32_t imm = getConstantOperandImmediateInt(op2);
+        andPtr(Imm32(imm), regT0);
+        if (imm >= 0)
+            emitFastArithIntToImmNoCheck(regT0, regT0);
+    } else {
+        emitGetVirtualRegisters(op1, regT0, op2, regT1);
+        andPtr(regT1, regT0);
+        emitJumpSlowCaseIfNotImmediateInteger(regT0);
+    }
+    emitPutVirtualRegister(result);
+}
+
+void JIT::emitSlow_op_bitand(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+
+    linkSlowCase(iter);
+    if (isOperandConstantImmediateInt(op1)) {
+        JITStubCall stubCall(this, cti_op_bitand);
+        stubCall.addArgument(op1, regT2);
+        stubCall.addArgument(regT0);
+        stubCall.call(result);
+    } else if (isOperandConstantImmediateInt(op2)) {
+        JITStubCall stubCall(this, cti_op_bitand);
+        stubCall.addArgument(regT0);
+        stubCall.addArgument(op2, regT2);
+        stubCall.call(result);
+    } else {
+        JITStubCall stubCall(this, cti_op_bitand);
+        stubCall.addArgument(op1, regT2);
+        stubCall.addArgument(regT1);
+        stubCall.call(result);
+    }
+}
+
+void JIT::emit_op_post_inc(Instruction* currentInstruction)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned srcDst = currentInstruction[2].u.operand;
+
+    emitGetVirtualRegister(srcDst, regT0);
+    move(regT0, regT1);
+    emitJumpSlowCaseIfNotImmediateInteger(regT0);
+    addSlowCase(branchAdd32(Overflow, TrustedImm32(1), regT1));
+    emitFastArithIntToImmNoCheck(regT1, regT1);
+    emitPutVirtualRegister(srcDst, regT1);
+    emitPutVirtualRegister(result);
+}
+
+void JIT::emitSlow_op_post_inc(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned srcDst = currentInstruction[2].u.operand;
+
+    linkSlowCase(iter);
+    linkSlowCase(iter);
+    JITStubCall stubCall(this, cti_op_post_inc);
+    stubCall.addArgument(regT0);
+    stubCall.addArgument(Imm32(srcDst));
+    stubCall.call(result);
+}
+
+void JIT::emit_op_post_dec(Instruction* currentInstruction)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned srcDst = currentInstruction[2].u.operand;
+
+    emitGetVirtualRegister(srcDst, regT0);
+    move(regT0, regT1);
+    emitJumpSlowCaseIfNotImmediateInteger(regT0);
+    addSlowCase(branchSub32(Overflow, TrustedImm32(1), regT1));
+    emitFastArithIntToImmNoCheck(regT1, regT1);
+    emitPutVirtualRegister(srcDst, regT1);
+    emitPutVirtualRegister(result);
+}
+
+void JIT::emitSlow_op_post_dec(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned srcDst = currentInstruction[2].u.operand;
+
+    linkSlowCase(iter);
+    linkSlowCase(iter);
+    JITStubCall stubCall(this, cti_op_post_dec);
+    stubCall.addArgument(regT0);
+    stubCall.addArgument(Imm32(srcDst));
+    stubCall.call(result);
+}
+
+void JIT::emit_op_pre_inc(Instruction* currentInstruction)
+{
+    unsigned srcDst = currentInstruction[1].u.operand;
+
+    emitGetVirtualRegister(srcDst, regT0);
+    emitJumpSlowCaseIfNotImmediateInteger(regT0);
+    addSlowCase(branchAdd32(Overflow, TrustedImm32(1), regT0));
+    emitFastArithIntToImmNoCheck(regT0, regT0);
+    emitPutVirtualRegister(srcDst);
+}
+
+void JIT::emitSlow_op_pre_inc(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned srcDst = currentInstruction[1].u.operand;
+
+    Jump notImm = getSlowCase(iter);
+    linkSlowCase(iter);
+    emitGetVirtualRegister(srcDst, regT0);
+    notImm.link(this);
+    JITStubCall stubCall(this, cti_op_pre_inc);
+    stubCall.addArgument(regT0);
+    stubCall.call(srcDst);
+}
+
+void JIT::emit_op_pre_dec(Instruction* currentInstruction)
+{
+    unsigned srcDst = currentInstruction[1].u.operand;
+
+    emitGetVirtualRegister(srcDst, regT0);
+    emitJumpSlowCaseIfNotImmediateInteger(regT0);
+    addSlowCase(branchSub32(Overflow, TrustedImm32(1), regT0));
+    emitFastArithIntToImmNoCheck(regT0, regT0);
+    emitPutVirtualRegister(srcDst);
+}
+
+void JIT::emitSlow_op_pre_dec(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned srcDst = currentInstruction[1].u.operand;
+
+    Jump notImm = getSlowCase(iter);
+    linkSlowCase(iter);
+    emitGetVirtualRegister(srcDst, regT0);
+    notImm.link(this);
+    JITStubCall stubCall(this, cti_op_pre_dec);
+    stubCall.addArgument(regT0);
+    stubCall.call(srcDst);
+}
+
+/* ------------------------------ BEGIN: OP_MOD ------------------------------ */
+
+#if CPU(X86) || CPU(X86_64) || CPU(MIPS)
+
+void JIT::emit_op_mod(Instruction* currentInstruction)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+
+#if CPU(X86) || CPU(X86_64)
+    // Make sure registers are correct for x86 IDIV instructions.
+    ASSERT(regT0 == X86Registers::eax);
+    ASSERT(regT1 == X86Registers::edx);
+    ASSERT(regT2 == X86Registers::ecx);
+#endif
+
+    emitGetVirtualRegisters(op1, regT0, op2, regT2);
+    emitJumpSlowCaseIfNotImmediateInteger(regT0);
+    emitJumpSlowCaseIfNotImmediateInteger(regT2);
+
+    addSlowCase(branchPtr(Equal, regT2, TrustedImmPtr(JSValue::encode(jsNumber(0)))));
+    m_assembler.cdq();
+    m_assembler.idivl_r(regT2);
+    emitFastArithReTagImmediate(regT1, regT0);
+    emitPutVirtualRegister(result);
+}
+
+void JIT::emitSlow_op_mod(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned result = currentInstruction[1].u.operand;
+
+    linkSlowCase(iter);
+    linkSlowCase(iter);
+    linkSlowCase(iter);
+    JITStubCall stubCall(this, cti_op_mod);
+    stubCall.addArgument(regT0);
+    stubCall.addArgument(regT2);
+    stubCall.call(result);
+}
+
+#else // CPU(X86) || CPU(X86_64) || CPU(MIPS)
+
+void JIT::emit_op_mod(Instruction* currentInstruction)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+
+    JITStubCall stubCall(this, cti_op_mod);
+    stubCall.addArgument(op1, regT2);
+    stubCall.addArgument(op2, regT2);
+    stubCall.call(result);
+}
+
+void JIT::emitSlow_op_mod(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+#if ENABLE(JIT_USE_SOFT_MODULO)
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+    linkSlowCase(iter);
+    linkSlowCase(iter);
+    linkSlowCase(iter);
+    JITStubCall stubCall(this, cti_op_mod);
+    stubCall.addArgument(op1, regT2);
+    stubCall.addArgument(op2, regT2);
+    stubCall.call(result);
+#else
+    ASSERT_NOT_REACHED();
+#endif
+}
+
+#endif // CPU(X86) || CPU(X86_64)
+
+/* ------------------------------ END: OP_MOD ------------------------------ */
+
+/* ------------------------------ BEGIN: USE(JSVALUE64) (OP_ADD, OP_SUB, OP_MUL) ------------------------------ */
+
+void JIT::compileBinaryArithOp(OpcodeID opcodeID, unsigned, unsigned op1, unsigned op2, OperandTypes)
+{
+    emitGetVirtualRegisters(op1, regT0, op2, regT1);
+    emitJumpSlowCaseIfNotImmediateInteger(regT0);
+    emitJumpSlowCaseIfNotImmediateInteger(regT1);
+#if ENABLE(VALUE_PROFILER)
+    RareCaseProfile* profile = m_codeBlock->addSpecialFastCaseProfile(m_bytecodeOffset);
+#endif
+    if (opcodeID == op_add)
+        addSlowCase(branchAdd32(Overflow, regT1, regT0));
+    else if (opcodeID == op_sub)
+        addSlowCase(branchSub32(Overflow, regT1, regT0));
+    else {
+        ASSERT(opcodeID == op_mul);
+#if ENABLE(VALUE_PROFILER)
+        if (m_canBeOptimized) {
+            // We want to be able to measure if this is taking the slow case just
+            // because of negative zero. If this produces positive zero, then we
+            // don't want the slow case to be taken because that will throw off
+            // speculative compilation.
+            move(regT0, regT2);
+            addSlowCase(branchMul32(Overflow, regT1, regT2));
+            JumpList done;
+            done.append(branchTest32(NonZero, regT2));
+            Jump negativeZero = branch32(LessThan, regT0, Imm32(0));
+            done.append(branch32(GreaterThanOrEqual, regT1, Imm32(0)));
+            negativeZero.link(this);
+            // We only get here if we have a genuine negative zero. Record this,
+            // so that the speculative JIT knows that we failed speculation
+            // because of a negative zero.
+            add32(Imm32(1), AbsoluteAddress(&profile->m_counter));
+            addSlowCase(jump());
+            done.link(this);
+            move(regT2, regT0);
+        } else {
+            addSlowCase(branchMul32(Overflow, regT1, regT0));
+            addSlowCase(branchTest32(Zero, regT0));
+        }
+#else
+        addSlowCase(branchMul32(Overflow, regT1, regT0));
+        addSlowCase(branchTest32(Zero, regT0));
+#endif
+    }
+    emitFastArithIntToImmNoCheck(regT0, regT0);
+}
+
+void JIT::compileBinaryArithOpSlowCase(OpcodeID opcodeID, Vector<SlowCaseEntry>::iterator& iter, unsigned result, unsigned op1, unsigned op2, OperandTypes types, bool op1HasImmediateIntFastCase, bool op2HasImmediateIntFastCase)
+{
+    // We assume that subtracting TagTypeNumber is equivalent to adding DoubleEncodeOffset.
+    COMPILE_ASSERT(((TagTypeNumber + DoubleEncodeOffset) == 0), TagTypeNumber_PLUS_DoubleEncodeOffset_EQUALS_0);
+
+    Jump notImm1;
+    Jump notImm2;
+    if (op1HasImmediateIntFastCase) {
+        notImm2 = getSlowCase(iter);
+    } else if (op2HasImmediateIntFastCase) {
+        notImm1 = getSlowCase(iter);
+    } else {
+        notImm1 = getSlowCase(iter);
+        notImm2 = getSlowCase(iter);
+    }
+
+    linkSlowCase(iter); // Integer overflow case - we could handle this in JIT code, but this is likely rare.
+    if (opcodeID == op_mul && !op1HasImmediateIntFastCase && !op2HasImmediateIntFastCase) // op_mul has an extra slow case to handle 0 * negative number.
+        linkSlowCase(iter);
+    emitGetVirtualRegister(op1, regT0);
+
+    Label stubFunctionCall(this);
+    JITStubCall stubCall(this, opcodeID == op_add ? cti_op_add : opcodeID == op_sub ? cti_op_sub : cti_op_mul);
+    if (op1HasImmediateIntFastCase || op2HasImmediateIntFastCase) {
+        emitGetVirtualRegister(op1, regT0);
+        emitGetVirtualRegister(op2, regT1);
+    }
+    stubCall.addArgument(regT0);
+    stubCall.addArgument(regT1);
+    stubCall.call(result);
+    Jump end = jump();
+
+    if (op1HasImmediateIntFastCase) {
+        notImm2.link(this);
+        if (!types.second().definitelyIsNumber())
+            emitJumpIfNotImmediateNumber(regT0).linkTo(stubFunctionCall, this);
+        emitGetVirtualRegister(op1, regT1);
+        convertInt32ToDouble(regT1, fpRegT1);
+        addPtr(tagTypeNumberRegister, regT0);
+        movePtrToDouble(regT0, fpRegT2);
+    } else if (op2HasImmediateIntFastCase) {
+        notImm1.link(this);
+        if (!types.first().definitelyIsNumber())
+            emitJumpIfNotImmediateNumber(regT0).linkTo(stubFunctionCall, this);
+        emitGetVirtualRegister(op2, regT1);
+        convertInt32ToDouble(regT1, fpRegT1);
+        addPtr(tagTypeNumberRegister, regT0);
+        movePtrToDouble(regT0, fpRegT2);
+    } else {
+        // if we get here, eax is not an int32, edx not yet checked.
+        notImm1.link(this);
+        if (!types.first().definitelyIsNumber())
+            emitJumpIfNotImmediateNumber(regT0).linkTo(stubFunctionCall, this);
+        if (!types.second().definitelyIsNumber())
+            emitJumpIfNotImmediateNumber(regT1).linkTo(stubFunctionCall, this);
+        addPtr(tagTypeNumberRegister, regT0);
+        movePtrToDouble(regT0, fpRegT1);
+        Jump op2isDouble = emitJumpIfNotImmediateInteger(regT1);
+        convertInt32ToDouble(regT1, fpRegT2);
+        Jump op2wasInteger = jump();
+
+        // if we get here, eax IS an int32, edx is not.
+        notImm2.link(this);
+        if (!types.second().definitelyIsNumber())
+            emitJumpIfNotImmediateNumber(regT1).linkTo(stubFunctionCall, this);
+        convertInt32ToDouble(regT0, fpRegT1);
+        op2isDouble.link(this);
+        addPtr(tagTypeNumberRegister, regT1);
+        movePtrToDouble(regT1, fpRegT2);
+        op2wasInteger.link(this);
+    }
+
+    if (opcodeID == op_add)
+        addDouble(fpRegT2, fpRegT1);
+    else if (opcodeID == op_sub)
+        subDouble(fpRegT2, fpRegT1);
+    else if (opcodeID == op_mul)
+        mulDouble(fpRegT2, fpRegT1);
+    else {
+        ASSERT(opcodeID == op_div);
+        divDouble(fpRegT2, fpRegT1);
+    }
+    moveDoubleToPtr(fpRegT1, regT0);
+    subPtr(tagTypeNumberRegister, regT0);
+    emitPutVirtualRegister(result, regT0);
+
+    end.link(this);
+}
+
+void JIT::emit_op_add(Instruction* currentInstruction)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+    OperandTypes types = OperandTypes::fromInt(currentInstruction[4].u.operand);
+
+    if (!types.first().mightBeNumber() || !types.second().mightBeNumber()) {
+        addSlowCase();
+        JITStubCall stubCall(this, cti_op_add);
+        stubCall.addArgument(op1, regT2);
+        stubCall.addArgument(op2, regT2);
+        stubCall.call(result);
+        return;
+    }
+
+    if (isOperandConstantImmediateInt(op1)) {
+        emitGetVirtualRegister(op2, regT0);
+        emitJumpSlowCaseIfNotImmediateInteger(regT0);
+        addSlowCase(branchAdd32(Overflow, Imm32(getConstantOperandImmediateInt(op1)), regT0));
+        emitFastArithIntToImmNoCheck(regT0, regT0);
+    } else if (isOperandConstantImmediateInt(op2)) {
+        emitGetVirtualRegister(op1, regT0);
+        emitJumpSlowCaseIfNotImmediateInteger(regT0);
+        addSlowCase(branchAdd32(Overflow, Imm32(getConstantOperandImmediateInt(op2)), regT0));
+        emitFastArithIntToImmNoCheck(regT0, regT0);
+    } else
+        compileBinaryArithOp(op_add, result, op1, op2, types);
+
+    emitPutVirtualRegister(result);
+}
+
+void JIT::emitSlow_op_add(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+    OperandTypes types = OperandTypes::fromInt(currentInstruction[4].u.operand);
+
+    if (!types.first().mightBeNumber() || !types.second().mightBeNumber()) {
+        linkDummySlowCase(iter);
+        return;
+    }
+
+    bool op1HasImmediateIntFastCase = isOperandConstantImmediateInt(op1);
+    bool op2HasImmediateIntFastCase = !op1HasImmediateIntFastCase && isOperandConstantImmediateInt(op2);
+    compileBinaryArithOpSlowCase(op_add, iter, result, op1, op2, types, op1HasImmediateIntFastCase, op2HasImmediateIntFastCase);
+}
+
+void JIT::emit_op_mul(Instruction* currentInstruction)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+    OperandTypes types = OperandTypes::fromInt(currentInstruction[4].u.operand);
+
+    // For now, only plant a fast int case if the constant operand is greater than zero.
+    int32_t value;
+    if (isOperandConstantImmediateInt(op1) && ((value = getConstantOperandImmediateInt(op1)) > 0)) {
+#if ENABLE(VALUE_PROFILER)
+        // Add a special fast case profile because the DFG JIT will expect one.
+        m_codeBlock->addSpecialFastCaseProfile(m_bytecodeOffset);
+#endif
+        emitGetVirtualRegister(op2, regT0);
+        emitJumpSlowCaseIfNotImmediateInteger(regT0);
+        addSlowCase(branchMul32(Overflow, Imm32(value), regT0, regT0));
+        emitFastArithReTagImmediate(regT0, regT0);
+    } else if (isOperandConstantImmediateInt(op2) && ((value = getConstantOperandImmediateInt(op2)) > 0)) {
+#if ENABLE(VALUE_PROFILER)
+        // Add a special fast case profile because the DFG JIT will expect one.
+        m_codeBlock->addSpecialFastCaseProfile(m_bytecodeOffset);
+#endif
+        emitGetVirtualRegister(op1, regT0);
+        emitJumpSlowCaseIfNotImmediateInteger(regT0);
+        addSlowCase(branchMul32(Overflow, Imm32(value), regT0, regT0));
+        emitFastArithReTagImmediate(regT0, regT0);
+    } else
+        compileBinaryArithOp(op_mul, result, op1, op2, types);
+
+    emitPutVirtualRegister(result);
+}
+
+void JIT::emitSlow_op_mul(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+    OperandTypes types = OperandTypes::fromInt(currentInstruction[4].u.operand);
+
+    bool op1HasImmediateIntFastCase = isOperandConstantImmediateInt(op1) && getConstantOperandImmediateInt(op1) > 0;
+    bool op2HasImmediateIntFastCase = !op1HasImmediateIntFastCase && isOperandConstantImmediateInt(op2) && getConstantOperandImmediateInt(op2) > 0;
+    compileBinaryArithOpSlowCase(op_mul, iter, result, op1, op2, types, op1HasImmediateIntFastCase, op2HasImmediateIntFastCase);
+}
+
+void JIT::emit_op_div(Instruction* currentInstruction)
+{
+    unsigned dst = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+    OperandTypes types = OperandTypes::fromInt(currentInstruction[4].u.operand);
+
+    if (isOperandConstantImmediateDouble(op1)) {
+        emitGetVirtualRegister(op1, regT0);
+        addPtr(tagTypeNumberRegister, regT0);
+        movePtrToDouble(regT0, fpRegT0);
+    } else if (isOperandConstantImmediateInt(op1)) {
+        emitLoadInt32ToDouble(op1, fpRegT0);
+    } else {
+        emitGetVirtualRegister(op1, regT0);
+        if (!types.first().definitelyIsNumber())
+            emitJumpSlowCaseIfNotImmediateNumber(regT0);
+        Jump notInt = emitJumpIfNotImmediateInteger(regT0);
+        convertInt32ToDouble(regT0, fpRegT0);
+        Jump skipDoubleLoad = jump();
+        notInt.link(this);
+        addPtr(tagTypeNumberRegister, regT0);
+        movePtrToDouble(regT0, fpRegT0);
+        skipDoubleLoad.link(this);
+    }
+
+    if (isOperandConstantImmediateDouble(op2)) {
+        emitGetVirtualRegister(op2, regT1);
+        addPtr(tagTypeNumberRegister, regT1);
+        movePtrToDouble(regT1, fpRegT1);
+    } else if (isOperandConstantImmediateInt(op2)) {
+        emitLoadInt32ToDouble(op2, fpRegT1);
+    } else {
+        emitGetVirtualRegister(op2, regT1);
+        if (!types.second().definitelyIsNumber())
+            emitJumpSlowCaseIfNotImmediateNumber(regT1);
+        Jump notInt = emitJumpIfNotImmediateInteger(regT1);
+        convertInt32ToDouble(regT1, fpRegT1);
+        Jump skipDoubleLoad = jump();
+        notInt.link(this);
+        addPtr(tagTypeNumberRegister, regT1);
+        movePtrToDouble(regT1, fpRegT1);
+        skipDoubleLoad.link(this);
+    }
+    divDouble(fpRegT1, fpRegT0);
+    
+#if ENABLE(VALUE_PROFILER)
+    // Is the result actually an integer? The DFG JIT would really like to know. If it's
+    // not an integer, we increment a count. If this together with the slow case counter
+    // are below threshold then the DFG JIT will compile this division with a specualtion
+    // that the remainder is zero.
+    
+    // As well, there are cases where a double result here would cause an important field
+    // in the heap to sometimes have doubles in it, resulting in double predictions getting
+    // propagated to a use site where it might cause damage (such as the index to an array
+    // access). So if we are DFG compiling anything in the program, we want this code to
+    // ensure that it produces integers whenever possible.
+    
+    // FIXME: This will fail to convert to integer if the result is zero. We should
+    // distinguish between positive zero and negative zero here.
+    
+    JumpList notInteger;
+    branchConvertDoubleToInt32(fpRegT0, regT0, notInteger, fpRegT1);
+    // If we've got an integer, we might as well make that the result of the division.
+    emitFastArithReTagImmediate(regT0, regT0);
+    Jump isInteger = jump();
+    notInteger.link(this);
+    add32(Imm32(1), AbsoluteAddress(&m_codeBlock->addSpecialFastCaseProfile(m_bytecodeOffset)->m_counter));
+    moveDoubleToPtr(fpRegT0, regT0);
+    subPtr(tagTypeNumberRegister, regT0);
+    isInteger.link(this);
+#else
+    // Double result.
+    moveDoubleToPtr(fpRegT0, regT0);
+    subPtr(tagTypeNumberRegister, regT0);
+#endif
+
+    emitPutVirtualRegister(dst, regT0);
+}
+
+void JIT::emitSlow_op_div(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+    OperandTypes types = OperandTypes::fromInt(currentInstruction[4].u.operand);
+    if (types.first().definitelyIsNumber() && types.second().definitelyIsNumber()) {
+#ifndef NDEBUG
+        breakpoint();
+#endif
+        return;
+    }
+    if (!isOperandConstantImmediateDouble(op1) && !isOperandConstantImmediateInt(op1)) {
+        if (!types.first().definitelyIsNumber())
+            linkSlowCase(iter);
+    }
+    if (!isOperandConstantImmediateDouble(op2) && !isOperandConstantImmediateInt(op2)) {
+        if (!types.second().definitelyIsNumber())
+            linkSlowCase(iter);
+    }
+    // There is an extra slow case for (op1 * -N) or (-N * op2), to check for 0 since this should produce a result of -0.
+    JITStubCall stubCall(this, cti_op_div);
+    stubCall.addArgument(op1, regT2);
+    stubCall.addArgument(op2, regT2);
+    stubCall.call(result);
+}
+
+void JIT::emit_op_sub(Instruction* currentInstruction)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+    OperandTypes types = OperandTypes::fromInt(currentInstruction[4].u.operand);
+
+    compileBinaryArithOp(op_sub, result, op1, op2, types);
+    emitPutVirtualRegister(result);
+}
+
+void JIT::emitSlow_op_sub(Instruction* currentInstruction, Vector<SlowCaseEntry>::iterator& iter)
+{
+    unsigned result = currentInstruction[1].u.operand;
+    unsigned op1 = currentInstruction[2].u.operand;
+    unsigned op2 = currentInstruction[3].u.operand;
+    OperandTypes types = OperandTypes::fromInt(currentInstruction[4].u.operand);
+
+    compileBinaryArithOpSlowCase(op_sub, iter, result, op1, op2, types, false, false);
+}
+
+/* ------------------------------ END: OP_ADD, OP_SUB, OP_MUL ------------------------------ */
+
+#endif // USE(JSVALUE64)
+
+} // namespace JSC
+
+#endif // ENABLE(JIT)