Index: lib/Target/X86/AsmParser/X86AsmInstrumentation.cpp
===================================================================
--- lib/Target/X86/AsmParser/X86AsmInstrumentation.cpp
+++ lib/Target/X86/AsmParser/X86AsmInstrumentation.cpp
@@ -751,7 +751,12 @@
 
 class X86AddressSanitizer64 : public X86AddressSanitizer {
 public:
+#ifndef _WIN64
   static const long kShadowOffset = 0x7fff8000;
+#else
+  // TODO(wwchrome): This value is experimental and may change.
+  static const long long kShadowOffset = 0x1ULL << 45; // 32TB
+#endif
 
   X86AddressSanitizer64(const MCSubtargetInfo *&STI)
       : X86AddressSanitizer(STI) {}
Index: lib/Transforms/Instrumentation/AddressSanitizer.cpp
===================================================================
--- lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -78,6 +78,8 @@
 static const uint64_t kFreeBSD_ShadowOffset32 = 1ULL << 30;
 static const uint64_t kFreeBSD_ShadowOffset64 = 1ULL << 46;
 static const uint64_t kWindowsShadowOffset32 = 3ULL << 28;
+// TODO(wwchrome): Experimental for asan Win64, may change.
+static const uint64_t kWindowsShadowOffset64 = 0x1ULL << 45;  // 32TB.
 
 static const size_t kMinStackMallocSize = 1 << 6;   // 64B
 static const size_t kMaxStackMallocSize = 1 << 16;  // 64K
@@ -396,7 +398,10 @@
         Mapping.Offset = kLinuxKasan_ShadowOffset64;
       else
         Mapping.Offset = kSmallX86_64ShadowOffset;
-    } else if (IsMIPS64)
+    } else if (IsWindows && IsX86_64) {
+      Mapping.Offset = kWindowsShadowOffset64;
+    }
+    else if (IsMIPS64)
       Mapping.Offset = kMIPS64_ShadowOffset64;
     else if (IsIOS)
       // If we're targeting iOS and x86, the binary is built for iOS simulator.