Index: llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
===================================================================
--- llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -2537,11 +2537,98 @@
     insertShadowCheck(Shadow, Origin, &I);
   }
 
+  void handleMaskedStore(IntrinsicInst &I) {
+    IRBuilder<> IRB(&I);
+    Value *V = I.getArgOperand(0);
+    Value *Addr = I.getArgOperand(1);
+    unsigned Align = cast<ConstantInt>(I.getArgOperand(2))->getZExtValue();
+    Value *Mask = I.getArgOperand(3);
+    Value *Shadow = getShadow(V);
+
+    Value *ShadowPtr;
+    Value *OriginPtr;
+    std::tie(ShadowPtr, OriginPtr) = getShadowOriginPtr(
+        Addr, IRB, Shadow->getType(), Align, /*isStore*/ true);
+
+    if (ClCheckAccessAddress) {
+      insertShadowCheck(Addr, &I);
+      // Uninitialized mask is kind of like uninitialized address, but not as
+      // scary.
+      insertShadowCheck(Mask, &I);
+    }
+
+    IRB.CreateMaskedStore(Shadow, ShadowPtr, Align, Mask);
+
+    if (MS.TrackOrigins) {
+      auto &DL = F.getParent()->getDataLayout();
+      paintOrigin(IRB, getOrigin(V), OriginPtr,
+                  DL.getTypeStoreSize(Shadow->getType()),
+                  std::max(Align, kMinOriginAlignment));
+    }
+  }
+
+  bool handleMaskedLoad(IntrinsicInst &I) {
+    IRBuilder<> IRB(&I);
+    Value *Addr = I.getArgOperand(0);
+    unsigned Align = cast<ConstantInt>(I.getArgOperand(1))->getZExtValue();
+    Value *Mask = I.getArgOperand(2);
+    Value *PassThru = I.getArgOperand(3);
+
+    Type *ShadowTy = getShadowTy(&I);
+    Value *ShadowPtr, *OriginPtr;
+    if (PropagateShadow) {
+      std::tie(ShadowPtr, OriginPtr) =
+          getShadowOriginPtr(Addr, IRB, ShadowTy, Align, /*isStore*/ false);
+      setShadow(&I, IRB.CreateMaskedLoad(ShadowPtr, Align, Mask,
+                                         getShadow(PassThru), "_msmaskedld"));
+    } else {
+      setShadow(&I, getCleanShadow(&I));
+    }
+
+    if (ClCheckAccessAddress) {
+      insertShadowCheck(Addr, &I);
+      insertShadowCheck(Mask, &I);
+    }
+
+    if (MS.TrackOrigins) {
+      if (PropagateShadow) {
+        // Choose between PassThru's and the loaded value's origins.
+        Value *MaskedPassThruShadow = IRB.CreateAnd(
+            getShadow(PassThru), IRB.CreateSExt(IRB.CreateNeg(Mask), ShadowTy));
+
+        Value *Acc = IRB.CreateExtractElement(
+            MaskedPassThruShadow, ConstantInt::get(IRB.getInt32Ty(), 0));
+        for (int i = 1, N = PassThru->getType()->getVectorNumElements(); i < N;
+             ++i) {
+          Value *More = IRB.CreateExtractElement(
+              MaskedPassThruShadow, ConstantInt::get(IRB.getInt32Ty(), i));
+          Acc = IRB.CreateOr(Acc, More);
+        }
+
+        Value *Origin = IRB.CreateSelect(
+            IRB.CreateICmpNE(Acc, Constant::getNullValue(Acc->getType())),
+            getOrigin(PassThru), IRB.CreateLoad(OriginPtr));
+
+        setOrigin(&I, Origin);
+      } else {
+        setOrigin(&I, getCleanOrigin());
+      }
+    }
+    return true;
+  }
+
+
   void visitIntrinsicInst(IntrinsicInst &I) {
     switch (I.getIntrinsicID()) {
     case Intrinsic::bswap:
       handleBswap(I);
       break;
+    case Intrinsic::masked_store:
+      handleMaskedStore(I);
+      break;
+    case Intrinsic::masked_load:
+      handleMaskedLoad(I);
+      break;
     case Intrinsic::x86_sse_stmxcsr:
       handleStmxcsr(I);
       break;
Index: llvm/test/Instrumentation/MemorySanitizer/masked-store-load.ll
===================================================================
--- /dev/null
+++ llvm/test/Instrumentation/MemorySanitizer/masked-store-load.ll
@@ -0,0 +1,124 @@
+; RUN: opt < %s -msan -msan-check-access-address=0 -S | FileCheck %s
+; RUN: opt < %s -msan -msan-check-access-address=0 -msan-track-origins=1 -S | FileCheck %s --check-prefixes=CHECK,CHECK-ORIGIN
+; RUN: opt < %s -msan -msan-check-access-address=1 -S | FileCheck %s --check-prefix=ADDR
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @llvm.masked.store.v4i64.p0v4i64(<4 x i64>, <4 x i64>*, i32, <4 x i1>)
+declare <4 x double> @llvm.masked.load.v4f64.p0v4f64(<4 x double>*, i32, <4 x i1>, <4 x double>)
+
+define void @Store(<4 x i64>* %p, <4 x i64> %v, <4 x i1> %mask) sanitize_memory {
+entry:
+  tail call void @llvm.masked.store.v4i64.p0v4i64(<4 x i64> %v, <4 x i64>* %p, i32 1, <4 x i1> %mask)
+  ret void
+}
+
+; CHECK-LABEL: @Store(
+; CHECK: %[[A:.*]] = load <4 x i64>, {{.*}}@__msan_param_tls to i64), i64 8)
+; CHECK-ORIGIN: %[[O:.*]] = load i32, {{.*}}@__msan_param_origin_tls to i64), i64 8)
+; CHECK: %[[B:.*]] = ptrtoint <4 x i64>* %p to i64
+; CHECK: %[[C:.*]] = xor i64 %[[B]], 87960930222080
+; CHECK: %[[D:.*]] = inttoptr i64 %[[C]] to <4 x i64>*
+; CHECK-ORIGIN: %[[E:.*]] = add i64 %[[C]], 17592186044416
+; CHECK-ORIGIN: %[[F:.*]] = and i64 %[[E]], -4
+; CHECK-ORIGIN: %[[G:.*]] = inttoptr i64 %[[F]] to i32*
+; CHECK: call void @llvm.masked.store.v4i64.p0v4i64(<4 x i64> %[[A]], <4 x i64>* %[[D]], i32 1, <4 x i1> %mask)
+; CHECK-ORIGIN: store i32 %[[O]], i32* %[[G]], align 4
+; CHECK-ORIGIN: getelementptr i32, i32* %[[G]], i32 1
+; CHECK-ORIGIN: store i32 %[[O]], i32* {{.*}}, align 4
+; CHECK-ORIGIN: getelementptr i32, i32* %[[G]], i32 2
+; CHECK-ORIGIN: store i32 %[[O]], i32* {{.*}}, align 4
+; CHECK-ORIGIN: getelementptr i32, i32* %[[G]], i32 3
+; CHECK-ORIGIN: store i32 %[[O]], i32* {{.*}}, align 4
+; CHECK-ORIGIN: getelementptr i32, i32* %[[G]], i32 4
+; CHECK-ORIGIN: store i32 %[[O]], i32* {{.*}}, align 4
+; CHECK-ORIGIN: getelementptr i32, i32* %[[G]], i32 5
+; CHECK-ORIGIN: store i32 %[[O]], i32* {{.*}}, align 4
+; CHECK-ORIGIN: getelementptr i32, i32* %[[G]], i32 6
+; CHECK-ORIGIN: store i32 %[[O]], i32* {{.*}}, align 4
+; CHECK-ORIGIN: getelementptr i32, i32* %[[G]], i32 7
+; CHECK-ORIGIN: store i32 %[[O]], i32* {{.*}}, align 4
+; CHECK: tail call void @llvm.masked.store.v4i64.p0v4i64(<4 x i64> %v, <4 x i64>* %p, i32 1, <4 x i1> %mask)
+; CHECK: ret void
+
+; ADDR-LABEL: @Store(
+; ADDR: %[[MASKSHADOW:.*]] = load <4 x i1>, {{.*}}@__msan_param_tls to i64), i64 40)
+; ADDR: %[[ADDRSHADOW:.*]] = load i64, {{.*}}[100 x i64]* @__msan_param_tls, i32 0, i32 0)
+
+; ADDR: %[[ADDRBAD:.*]] = icmp ne i64 %[[ADDRSHADOW]], 0
+; ADDR: br i1 %[[ADDRBAD]], label {{.*}}, label {{.*}}
+; ADDR: call void @__msan_warning_noreturn()
+
+; ADDR: %[[MASKSHADOWFLAT:.*]] = bitcast <4 x i1> %[[MASKSHADOW]] to i4
+; ADDR: %[[MASKBAD:.*]] = icmp ne i4 %[[MASKSHADOWFLAT]], 0
+; ADDR: br i1 %[[MASKBAD]], label {{.*}}, label {{.*}}
+; ADDR: call void @__msan_warning_noreturn()
+
+; ADDR: tail call void @llvm.masked.store.v4i64.p0v4i64(<4 x i64> %v, <4 x i64>* %p, i32 1, <4 x i1> %mask)
+; ADDR: ret void
+
+
+define <4 x double> @Load(<4 x double>* %p, <4 x double> %v, <4 x i1> %mask) sanitize_memory {
+entry:
+  %x = call <4 x double> @llvm.masked.load.v4f64.p0v4f64(<4 x double>* %p, i32 1, <4 x i1> %mask, <4 x double> %v)
+  ret <4 x double> %x
+}
+
+; CHECK-LABEL: @Load(
+; CHECK: %[[A:.*]] = load <4 x i64>, {{.*}}@__msan_param_tls to i64), i64 8)
+; CHECK-ORIGIN: %[[O:.*]] = load i32, {{.*}}@__msan_param_origin_tls to i64), i64 8)
+; CHECK: %[[B:.*]] = ptrtoint <4 x double>* %p to i64
+; CHECK: %[[C:.*]] = xor i64 %[[B]], 87960930222080
+; CHECK: %[[D:.*]] = inttoptr i64 %[[C]] to <4 x i64>*
+; CHECK-ORIGIN: %[[E:.*]] = add i64 %[[C]], 17592186044416
+; CHECK-ORIGIN: %[[F:.*]] = and i64 %[[E]], -4
+; CHECK-ORIGIN: %[[G:.*]] = inttoptr i64 %[[F]] to i32*
+; CHECK: %[[E:.*]] = call <4 x i64> @llvm.masked.load.v4i64.p0v4i64(<4 x i64>* %[[D]], i32 1, <4 x i1> %mask, <4 x i64> %[[A]])
+; CHECK-ORIGIN: %[[H:.*]] = load i32, i32* %[[G]]
+; CHECK-ORIGIN: %[[O2:.*]] = select i1 %{{.*}}, i32 %[[O]], i32 %[[H]]
+; CHECK: %[[X:.*]] = call <4 x double> @llvm.masked.load.v4f64.p0v4f64(<4 x double>* %p, i32 1, <4 x i1> %mask, <4 x double> %v)
+; CHECK: store <4 x i64> %[[E]], {{.*}}@__msan_retval_tls
+; CHECK-ORIGIN: store i32 %[[O2]], i32* @__msan_retval_origin_tls
+; CHECK: ret <4 x double> %[[X]]
+
+; ADDR-LABEL: @Load(
+; ADDR: %[[MASKSHADOW:.*]] = load <4 x i1>, {{.*}}@__msan_param_tls to i64), i64 40)
+; ADDR: %[[ADDRSHADOW:.*]] = load i64, {{.*}}[100 x i64]* @__msan_param_tls, i32 0, i32 0)
+
+; ADDR: %[[ADDRBAD:.*]] = icmp ne i64 %[[ADDRSHADOW]], 0
+; ADDR: br i1 %[[ADDRBAD]], label {{.*}}, label {{.*}}
+; ADDR: call void @__msan_warning_noreturn()
+
+; ADDR: %[[MASKSHADOWFLAT:.*]] = bitcast <4 x i1> %[[MASKSHADOW]] to i4
+; ADDR: %[[MASKBAD:.*]] = icmp ne i4 %[[MASKSHADOWFLAT]], 0
+; ADDR: br i1 %[[MASKBAD]], label {{.*}}, label {{.*}}
+; ADDR: call void @__msan_warning_noreturn()
+
+; ADDR: = call <4 x double> @llvm.masked.load.v4f64.p0v4f64(<4 x double>* %p, i32 1, <4 x i1> %mask, <4 x double> %v)
+; ADDR: ret <4 x double>
+
+define void @StoreNoSanitize(<4 x i64>* %p, <4 x i64> %v, <4 x i1> %mask) {
+entry:
+  tail call void @llvm.masked.store.v4i64.p0v4i64(<4 x i64> %v, <4 x i64>* %p, i32 1, <4 x i1> %mask)
+  ret void
+}
+
+; CHECK-LABEL: @StoreNoSanitize(
+; CHECK: %[[B:.*]] = ptrtoint <4 x i64>* %p to i64
+; CHECK: %[[C:.*]] = xor i64 %[[B]], 87960930222080
+; CHECK: %[[D:.*]] = inttoptr i64 %[[C]] to <4 x i64>*
+; CHECK: call void @llvm.masked.store.v4i64.p0v4i64(<4 x i64> zeroinitializer, <4 x i64>* %[[D]], i32 1, <4 x i1> %mask)
+; CHECK: tail call void @llvm.masked.store.v4i64.p0v4i64(<4 x i64> %v, <4 x i64>* %p, i32 1, <4 x i1> %mask)
+; CHECK: ret void
+
+define <4 x double> @LoadNoSanitize(<4 x double>* %p, <4 x double> %v, <4 x i1> %mask) {
+entry:
+  %x = call <4 x double> @llvm.masked.load.v4f64.p0v4f64(<4 x double>* %p, i32 1, <4 x i1> %mask, <4 x double> %v)
+  ret <4 x double> %x
+}
+
+; CHECK-LABEL: @LoadNoSanitize(
+; CHECK: %[[X:.*]] = call <4 x double> @llvm.masked.load.v4f64.p0v4f64(<4 x double>* %p, i32 1, <4 x i1> %mask, <4 x double> %v)
+; CHECK: store <4 x i64> zeroinitializer, {{.*}}@__msan_retval_tls to <4 x i64>*)
+; CHECK: ret <4 x double> %[[X]]