diff --git a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
--- a/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/MemorySanitizer.cpp
@@ -2137,8 +2137,14 @@
     if (PropagateShadow) {
       std::tie(ShadowPtr, OriginPtr) =
           getShadowOriginPtr(Addr, IRB, ShadowTy, Alignment, /*isStore*/ false);
-      setShadow(&I,
-                IRB.CreateAlignedLoad(ShadowTy, ShadowPtr, Alignment, "_msld"));
+      if (I.getMetadata(LLVMContext::MD_noundef)) {
+        insertShadowCheck(
+            IRB.CreateAlignedLoad(ShadowTy, ShadowPtr, Alignment, "_msld"), &I);
+        setShadow(&I, getCleanShadow(&I));
+      } else {
+        setShadow(
+            &I, IRB.CreateAlignedLoad(ShadowTy, ShadowPtr, Alignment, "_msld"));
+      }
     } else {
       setShadow(&I, getCleanShadow(&I));
     }