Index: lib/Transforms/Instrumentation/MemorySanitizer.cpp
===================================================================
--- lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -121,8 +121,12 @@
 #define DEBUG_TYPE "msan"
 
 static const uint64_t kShadowMask32 = 1ULL << 31;
+static const uint64_t kMIPS32_ShadowMask32 = 0x40000000UL;
 static const uint64_t kShadowMask64 = 1ULL << 46;
+static const uint64_t kMIPS64_ShadowMask64 = 0x4000000000ULL;
 static const uint64_t kOriginOffset32 = 1ULL << 30;
+static const uint64_t kMIPS32_OriginOffset32 = 0x20000000UL;
+static const uint64_t kMIPS64_OriginOffset64 = 0x2000000000ULL;
 static const uint64_t kOriginOffset64 = 1ULL << 45;
 static const unsigned kMinOriginAlignment = 4;
 static const unsigned kShadowTLSAlignment = 8;
@@ -423,6 +427,14 @@
 ///
 /// inserts a call to __msan_init to the module's constructor list.
 bool MemorySanitizer::doInitialization(Module &M) {
+  llvm::Triple TargetTriple(M.getTargetTriple());
+  bool IsMIPS32 = TargetTriple.getArch() == llvm::Triple::mips ||
+                  TargetTriple.getArch() == llvm::Triple::mipsel;
+  bool IsMIPS64 = TargetTriple.getArch() == llvm::Triple::mips64 ||
+                  TargetTriple.getArch() == llvm::Triple::mips64el;
+  bool IsX86_64 = TargetTriple.getArch() == llvm::Triple::x86_64;
+  bool IsX86 = TargetTriple.getArch() == llvm::Triple::x86;
+
   DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
   if (!DLP)
     report_fatal_error("data layout missing");
@@ -432,12 +444,22 @@
   unsigned PtrSize = DL->getPointerSizeInBits(/* AddressSpace */0);
   switch (PtrSize) {
     case 64:
-      ShadowMask = kShadowMask64;
-      OriginOffset = kOriginOffset64;
+      if (IsMIPS64) {
+        ShadowMask = kMIPS64_ShadowMask64;
+        OriginOffset = kMIPS64_OriginOffset64;
+      } else if (IsX86_64) {
+        ShadowMask = kShadowMask64;
+        OriginOffset = kOriginOffset64;
+      }
       break;
     case 32:
-      ShadowMask = kShadowMask32;
-      OriginOffset = kOriginOffset32;
+      if (IsMIPS32) {
+        ShadowMask = kMIPS32_ShadowMask32;
+        OriginOffset = kMIPS32_OriginOffset32;
+      } else if (IsX86) {
+        ShadowMask = kShadowMask32;
+        OriginOffset = kOriginOffset32;
+      }
       break;
     default:
       report_fatal_error("unsupported pointer size");