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diff --git a/Source/JavaScriptCore/jit/JITMulGenerator.cpp b/Source/JavaScriptCore/jit/JITMulGenerator.cpp
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index 000000000..b1fb0b0d0
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+++ b/Source/JavaScriptCore/jit/JITMulGenerator.cpp
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+/*
+ * Copyright (C) 2015 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"
+#include "JITMulGenerator.h"
+
+#if ENABLE(JIT)
+
+namespace JSC {
+
+void JITMulGenerator::generateFastPath(CCallHelpers& jit)
+{
+    ASSERT(m_scratchGPR != InvalidGPRReg);
+    ASSERT(m_scratchGPR != m_left.payloadGPR());
+    ASSERT(m_scratchGPR != m_right.payloadGPR());
+#if USE(JSVALUE64)
+    ASSERT(m_scratchGPR != m_result.payloadGPR());
+#else
+    ASSERT(m_scratchGPR != m_left.tagGPR());
+    ASSERT(m_scratchGPR != m_right.tagGPR());
+    ASSERT(m_scratchFPR != InvalidFPRReg);
+#endif
+
+    ASSERT(!m_leftOperand.isPositiveConstInt32() || !m_rightOperand.isPositiveConstInt32());
+
+    if (!m_leftOperand.mightBeNumber() || !m_rightOperand.mightBeNumber()) {
+        ASSERT(!m_didEmitFastPath);
+        return;
+    }
+
+    m_didEmitFastPath = true;
+
+    if (m_leftOperand.isPositiveConstInt32() || m_rightOperand.isPositiveConstInt32()) {
+        JSValueRegs var = m_leftOperand.isPositiveConstInt32() ? m_right : m_left;
+        SnippetOperand& varOpr = m_leftOperand.isPositiveConstInt32() ? m_rightOperand : m_leftOperand;
+        SnippetOperand& constOpr = m_leftOperand.isPositiveConstInt32() ? m_leftOperand : m_rightOperand;
+
+        // Try to do intVar * intConstant.
+        CCallHelpers::Jump notInt32 = jit.branchIfNotInt32(var);
+
+        GPRReg multiplyResultGPR = m_result.payloadGPR();
+        if (multiplyResultGPR == var.payloadGPR())
+            multiplyResultGPR = m_scratchGPR;
+
+        m_slowPathJumpList.append(jit.branchMul32(CCallHelpers::Overflow, var.payloadGPR(), CCallHelpers::Imm32(constOpr.asConstInt32()), multiplyResultGPR));
+
+        jit.boxInt32(multiplyResultGPR, m_result);
+        m_endJumpList.append(jit.jump());
+
+        if (!jit.supportsFloatingPoint()) {
+            m_slowPathJumpList.append(notInt32);
+            return;
+        }
+
+        // Try to do doubleVar * double(intConstant).
+        notInt32.link(&jit);
+        if (!varOpr.definitelyIsNumber())
+            m_slowPathJumpList.append(jit.branchIfNotNumber(var, m_scratchGPR));
+
+        jit.unboxDoubleNonDestructive(var, m_leftFPR, m_scratchGPR, m_scratchFPR);
+
+        jit.move(CCallHelpers::Imm32(constOpr.asConstInt32()), m_scratchGPR);
+        jit.convertInt32ToDouble(m_scratchGPR, m_rightFPR);
+
+        // Fall thru to doubleVar * doubleVar.
+
+    } else {
+        ASSERT(!m_leftOperand.isPositiveConstInt32() && !m_rightOperand.isPositiveConstInt32());
+
+        CCallHelpers::Jump leftNotInt;
+        CCallHelpers::Jump rightNotInt;
+
+        // Try to do intVar * intVar.
+        leftNotInt = jit.branchIfNotInt32(m_left);
+        rightNotInt = jit.branchIfNotInt32(m_right);
+
+        m_slowPathJumpList.append(jit.branchMul32(CCallHelpers::Overflow, m_right.payloadGPR(), m_left.payloadGPR(), m_scratchGPR));
+        m_slowPathJumpList.append(jit.branchTest32(CCallHelpers::Zero, m_scratchGPR)); // Go slow if potential negative zero.
+
+        jit.boxInt32(m_scratchGPR, m_result);
+        m_endJumpList.append(jit.jump());
+
+        if (!jit.supportsFloatingPoint()) {
+            m_slowPathJumpList.append(leftNotInt);
+            m_slowPathJumpList.append(rightNotInt);
+            return;
+        }
+
+        leftNotInt.link(&jit);
+        if (!m_leftOperand.definitelyIsNumber())
+            m_slowPathJumpList.append(jit.branchIfNotNumber(m_left, m_scratchGPR));
+        if (!m_rightOperand.definitelyIsNumber())
+            m_slowPathJumpList.append(jit.branchIfNotNumber(m_right, m_scratchGPR));
+
+        jit.unboxDoubleNonDestructive(m_left, m_leftFPR, m_scratchGPR, m_scratchFPR);
+        CCallHelpers::Jump rightIsDouble = jit.branchIfNotInt32(m_right);
+
+        jit.convertInt32ToDouble(m_right.payloadGPR(), m_rightFPR);
+        CCallHelpers::Jump rightWasInteger = jit.jump();
+
+        rightNotInt.link(&jit);
+        if (!m_rightOperand.definitelyIsNumber())
+            m_slowPathJumpList.append(jit.branchIfNotNumber(m_right, m_scratchGPR));
+
+        jit.convertInt32ToDouble(m_left.payloadGPR(), m_leftFPR);
+
+        rightIsDouble.link(&jit);
+        jit.unboxDoubleNonDestructive(m_right, m_rightFPR, m_scratchGPR, m_scratchFPR);
+
+        rightWasInteger.link(&jit);
+
+        // Fall thru to doubleVar * doubleVar.
+    }
+
+    // Do doubleVar * doubleVar.
+    jit.mulDouble(m_rightFPR, m_leftFPR);
+
+    if (!m_resultProfile)
+        jit.boxDouble(m_leftFPR, m_result);
+    else {
+        // The Int52 overflow check below intentionally omits 1ll << 51 as a valid negative Int52 value.
+        // Therefore, we will get a false positive if the result is that value. This is intentionally
+        // done to simplify the checking algorithm.
+
+        const int64_t negativeZeroBits = 1ll << 63;
+#if USE(JSVALUE64)
+        jit.moveDoubleTo64(m_leftFPR, m_result.payloadGPR());
+        CCallHelpers::Jump notNegativeZero = jit.branch64(CCallHelpers::NotEqual, m_result.payloadGPR(), CCallHelpers::TrustedImm64(negativeZeroBits));
+
+        jit.or32(CCallHelpers::TrustedImm32(ResultProfile::NegZeroDouble), CCallHelpers::AbsoluteAddress(m_resultProfile->addressOfFlags()));
+        CCallHelpers::Jump done = jit.jump();
+
+        notNegativeZero.link(&jit);
+        jit.or32(CCallHelpers::TrustedImm32(ResultProfile::NonNegZeroDouble), CCallHelpers::AbsoluteAddress(m_resultProfile->addressOfFlags()));
+
+        jit.move(m_result.payloadGPR(), m_scratchGPR);
+        jit.urshiftPtr(CCallHelpers::Imm32(52), m_scratchGPR);
+        jit.and32(CCallHelpers::Imm32(0x7ff), m_scratchGPR);
+        CCallHelpers::Jump noInt52Overflow = jit.branch32(CCallHelpers::LessThanOrEqual, m_scratchGPR, CCallHelpers::TrustedImm32(0x431));
+
+        jit.or32(CCallHelpers::TrustedImm32(ResultProfile::Int52Overflow), CCallHelpers::AbsoluteAddress(m_resultProfile->addressOfFlags()));
+        noInt52Overflow.link(&jit);
+
+        done.link(&jit);
+        jit.sub64(GPRInfo::tagTypeNumberRegister, m_result.payloadGPR()); // Box the double.
+#else
+        jit.boxDouble(m_leftFPR, m_result);
+        CCallHelpers::JumpList notNegativeZero;
+        notNegativeZero.append(jit.branch32(CCallHelpers::NotEqual, m_result.payloadGPR(), CCallHelpers::TrustedImm32(0)));
+        notNegativeZero.append(jit.branch32(CCallHelpers::NotEqual, m_result.tagGPR(), CCallHelpers::TrustedImm32(negativeZeroBits >> 32)));
+
+        jit.or32(CCallHelpers::TrustedImm32(ResultProfile::NegZeroDouble), CCallHelpers::AbsoluteAddress(m_resultProfile->addressOfFlags()));
+        CCallHelpers::Jump done = jit.jump();
+
+        notNegativeZero.link(&jit);
+        jit.or32(CCallHelpers::TrustedImm32(ResultProfile::NonNegZeroDouble), CCallHelpers::AbsoluteAddress(m_resultProfile->addressOfFlags()));
+
+        jit.move(m_result.tagGPR(), m_scratchGPR);
+        jit.urshiftPtr(CCallHelpers::Imm32(52 - 32), m_scratchGPR);
+        jit.and32(CCallHelpers::Imm32(0x7ff), m_scratchGPR);
+        CCallHelpers::Jump noInt52Overflow = jit.branch32(CCallHelpers::LessThanOrEqual, m_scratchGPR, CCallHelpers::TrustedImm32(0x431));
+        
+        jit.or32(CCallHelpers::TrustedImm32(ResultProfile::Int52Overflow), CCallHelpers::AbsoluteAddress(m_resultProfile->addressOfFlags()));
+
+        m_endJumpList.append(noInt52Overflow);
+        if (m_scratchGPR == m_result.tagGPR() || m_scratchGPR == m_result.payloadGPR())
+            jit.boxDouble(m_leftFPR, m_result);
+
+        m_endJumpList.append(done);
+#endif
+    }
+}
+
+} // namespace JSC
+
+#endif // ENABLE(JIT)