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diff --git a/Source/JavaScriptCore/jit/JITNegGenerator.cpp b/Source/JavaScriptCore/jit/JITNegGenerator.cpp
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+++ b/Source/JavaScriptCore/jit/JITNegGenerator.cpp
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+/*
+ * Copyright (C) 2015, 2016 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 "JITNegGenerator.h"
+
+#include "ArithProfile.h"
+
+#if ENABLE(JIT)
+
+namespace JSC {
+
+JITMathICInlineResult JITNegGenerator::generateInline(CCallHelpers& jit, MathICGenerationState& state, const ArithProfile* arithProfile)
+{
+    ASSERT(m_scratchGPR != InvalidGPRReg);
+    ASSERT(m_scratchGPR != m_src.payloadGPR());
+    ASSERT(m_scratchGPR != m_result.payloadGPR());
+#if USE(JSVALUE32_64)
+    ASSERT(m_scratchGPR != m_src.tagGPR());
+    ASSERT(m_scratchGPR != m_result.tagGPR());
+#endif
+
+    // We default to speculating int32.
+    ObservedType observedTypes = ObservedType().withInt32();
+    if (arithProfile)
+        observedTypes = arithProfile->lhsObservedType();
+    ASSERT_WITH_MESSAGE(!observedTypes.isEmpty(), "We should not attempt to generate anything if we do not have a profile.");
+
+    if (observedTypes.isOnlyNonNumber())
+        return JITMathICInlineResult::DontGenerate;
+
+    if (observedTypes.isOnlyInt32()) {
+        jit.moveValueRegs(m_src, m_result);
+        state.slowPathJumps.append(jit.branchIfNotInt32(m_src));
+        state.slowPathJumps.append(jit.branchTest32(CCallHelpers::Zero, m_src.payloadGPR(), CCallHelpers::TrustedImm32(0x7fffffff)));
+        jit.neg32(m_result.payloadGPR());
+#if USE(JSVALUE64)
+        jit.boxInt32(m_result.payloadGPR(), m_result);
+#endif
+
+        return JITMathICInlineResult::GeneratedFastPath;
+    }
+    if (observedTypes.isOnlyNumber()) {
+        state.slowPathJumps.append(jit.branchIfInt32(m_src));
+        state.slowPathJumps.append(jit.branchIfNotNumber(m_src, m_scratchGPR));
+#if USE(JSVALUE64)
+        if (m_src.payloadGPR() != m_result.payloadGPR()) {
+            jit.move(CCallHelpers::TrustedImm64(static_cast<int64_t>(1ull << 63)), m_result.payloadGPR());
+            jit.xor64(m_src.payloadGPR(), m_result.payloadGPR());
+        } else {
+            jit.move(CCallHelpers::TrustedImm64(static_cast<int64_t>(1ull << 63)), m_scratchGPR);
+            jit.xor64(m_scratchGPR, m_result.payloadGPR());
+        }
+#else
+        jit.moveValueRegs(m_src, m_result);
+        jit.xor32(CCallHelpers::TrustedImm32(1 << 31), m_result.tagGPR());
+#endif
+        return JITMathICInlineResult::GeneratedFastPath;
+    }
+    return JITMathICInlineResult::GenerateFullSnippet;
+}
+
+bool JITNegGenerator::generateFastPath(CCallHelpers& jit, CCallHelpers::JumpList& endJumpList, CCallHelpers::JumpList& slowPathJumpList, const ArithProfile* arithProfile, bool shouldEmitProfiling)
+{
+    ASSERT(m_scratchGPR != m_src.payloadGPR());
+    ASSERT(m_scratchGPR != m_result.payloadGPR());
+    ASSERT(m_scratchGPR != InvalidGPRReg);
+#if USE(JSVALUE32_64)
+    ASSERT(m_scratchGPR != m_src.tagGPR());
+    ASSERT(m_scratchGPR != m_result.tagGPR());
+#endif
+
+    jit.moveValueRegs(m_src, m_result);
+    CCallHelpers::Jump srcNotInt = jit.branchIfNotInt32(m_src);
+
+    // -0 should produce a double, and hence cannot be negated as an int.
+    // The negative int32 0x80000000 doesn't have a positive int32 representation, and hence cannot be negated as an int.
+    slowPathJumpList.append(jit.branchTest32(CCallHelpers::Zero, m_src.payloadGPR(), CCallHelpers::TrustedImm32(0x7fffffff)));
+
+    jit.neg32(m_result.payloadGPR());
+#if USE(JSVALUE64)
+    jit.boxInt32(m_result.payloadGPR(), m_result);
+#endif
+    endJumpList.append(jit.jump());
+
+    srcNotInt.link(&jit);
+    slowPathJumpList.append(jit.branchIfNotNumber(m_src, m_scratchGPR));
+
+    // For a double, all we need to do is to invert the sign bit.
+#if USE(JSVALUE64)
+    jit.move(CCallHelpers::TrustedImm64((int64_t)(1ull << 63)), m_scratchGPR);
+    jit.xor64(m_scratchGPR, m_result.payloadGPR());
+#else
+    jit.xor32(CCallHelpers::TrustedImm32(1 << 31), m_result.tagGPR());
+#endif
+    // The flags of ArithNegate are basic in DFG.
+    // We only need to know if we ever produced a number.
+    if (shouldEmitProfiling && arithProfile && !arithProfile->lhsObservedType().sawNumber() && !arithProfile->didObserveDouble())
+        arithProfile->emitSetDouble(jit);
+    return true;
+}
+
+} // namespace JSC
+
+#endif // ENABLE(JIT)