Checking in vendor folder for ease of using go get.

vendor/golang.org/x/sys/cpu/cpu_x86.go

@@ -0,0 +1,55 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build 386 amd64 amd64p32
+
+package cpu
+
+const cacheLineSize = 64
+
+func init() {
+	maxID, _, _, _ := cpuid(0, 0)
+
+	if maxID < 1 {
+		return
+	}
+
+	_, _, ecx1, edx1 := cpuid(1, 0)
+	X86.HasSSE2 = isSet(26, edx1)
+
+	X86.HasSSE3 = isSet(0, ecx1)
+	X86.HasPCLMULQDQ = isSet(1, ecx1)
+	X86.HasSSSE3 = isSet(9, ecx1)
+	X86.HasFMA = isSet(12, ecx1)
+	X86.HasSSE41 = isSet(19, ecx1)
+	X86.HasSSE42 = isSet(20, ecx1)
+	X86.HasPOPCNT = isSet(23, ecx1)
+	X86.HasAES = isSet(25, ecx1)
+	X86.HasOSXSAVE = isSet(27, ecx1)
+
+	osSupportsAVX := false
+	// For XGETBV, OSXSAVE bit is required and sufficient.
+	if X86.HasOSXSAVE {
+		eax, _ := xgetbv()
+		// Check if XMM and YMM registers have OS support.
+		osSupportsAVX = isSet(1, eax) && isSet(2, eax)
+	}
+
+	X86.HasAVX = isSet(28, ecx1) && osSupportsAVX
+
+	if maxID < 7 {
+		return
+	}
+
+	_, ebx7, _, _ := cpuid(7, 0)
+	X86.HasBMI1 = isSet(3, ebx7)
+	X86.HasAVX2 = isSet(5, ebx7) && osSupportsAVX
+	X86.HasBMI2 = isSet(8, ebx7)
+	X86.HasERMS = isSet(9, ebx7)
+	X86.HasADX = isSet(19, ebx7)
+}
+
+func isSet(bitpos uint, value uint32) bool {
+	return value&(1<<bitpos) != 0
+}