diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -2724,6 +2724,10 @@
         if (DoesKMove)
           K->setMetadata(Kind, JMD);
         break;
+      case LLVMContext::MD_nontemporal:
+        // Preserve !nontemporal if it is present on both instructions.
+        K->setMetadata(Kind, JMD);
+        break;
     }
   }
   // Set !invariant.group from J if J has it. If both instructions have it
@@ -2746,7 +2750,8 @@
       LLVMContext::MD_invariant_group, LLVMContext::MD_align,
       LLVMContext::MD_dereferenceable,
       LLVMContext::MD_dereferenceable_or_null,
-      LLVMContext::MD_access_group,    LLVMContext::MD_preserve_access_index};
+      LLVMContext::MD_access_group,    LLVMContext::MD_preserve_access_index,
+      LLVMContext::MD_nontemporal};
   combineMetadata(K, J, KnownIDs, KDominatesJ);
 }
 
@@ -2831,7 +2836,7 @@
       LLVMContext::MD_fpmath,          LLVMContext::MD_invariant_load,
       LLVMContext::MD_invariant_group, LLVMContext::MD_nonnull,
       LLVMContext::MD_access_group,    LLVMContext::MD_preserve_access_index,
-      LLVMContext::MD_noundef};
+      LLVMContext::MD_noundef,         LLVMContext::MD_nontemporal};
   combineMetadata(ReplInst, I, KnownIDs, false);
 }
 
diff --git a/llvm/test/Transforms/GVN/nontemporal.ll b/llvm/test/Transforms/GVN/nontemporal.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Transforms/GVN/nontemporal.ll
@@ -0,0 +1,30 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=gvn -S < %s | FileCheck %s
+
+; Check that !nontemporal metadata is preserved only if both original
+; instructions are marked.
+define i64 @one_nontemporal(ptr %p) {
+; CHECK-LABEL: @one_nontemporal(
+; CHECK-NEXT:    [[A:%.*]] = load i64, ptr [[P:%.*]], align 4
+; CHECK-NEXT:    [[C:%.*]] = add i64 [[A]], [[A]]
+; CHECK-NEXT:    ret i64 [[C]]
+;
+  %a = load i64, ptr %p
+  %b = load i64, ptr %p, !nontemporal !0
+  %c = add i64 %a, %b
+  ret i64 %c
+}
+
+define i64 @both_nontemporal(ptr %p) {
+; CHECK-LABEL: @both_nontemporal(
+; CHECK-NEXT:    [[A:%.*]] = load i64, ptr [[P:%.*]], align 4, !nontemporal !0
+; CHECK-NEXT:    [[C:%.*]] = add i64 [[A]], [[A]]
+; CHECK-NEXT:    ret i64 [[C]]
+;
+  %a = load i64, ptr %p, !nontemporal !0
+  %b = load i64, ptr %p, !nontemporal !0
+  %c = add i64 %a, %b
+  ret i64 %c
+}
+
+!0 = !{i32 1}
diff --git a/llvm/test/Transforms/GVNSink/sink-combine-metadata.ll b/llvm/test/Transforms/GVNSink/sink-combine-metadata.ll
--- a/llvm/test/Transforms/GVNSink/sink-combine-metadata.ll
+++ b/llvm/test/Transforms/GVNSink/sink-combine-metadata.ll
@@ -51,5 +51,49 @@
   ret ptr %c
 }
 
+; Check that nontemporal markings are propagated if both original stores are
+; marked.
+; CHECK-LABEL: @nontemporal(
+; CHECK-LABEL: if.end:
+; CHECK: !nontemporal
+; CHECK: ret void
+define void @nontemporal(i1 zeroext %flag, ptr %p) {
+entry:
+  br i1 %flag, label %if.then, label %if.else
+
+if.then:
+  %a = load ptr, ptr %p
+  store ptr %p, ptr %a, align 8, !nontemporal !1
+  br label %if.end
+
+if.else:
+  %b = load ptr, ptr %p
+  store ptr %p, ptr %b, align 8, !nontemporal !1
+  br label %if.end
+
+if.end:
+  ret void
+}
+
+; CHECK-LABEL: @nontemporal_mismatch(
+; CHECK-NOT: !nontemporal
+define void @nontemporal_mismatch(i1 zeroext %flag, ptr %p) {
+entry:
+  br i1 %flag, label %if.then, label %if.else
+
+if.then:
+  %a = load ptr, ptr %p
+  store ptr %p, ptr %a, align 8
+  br label %if.end
+
+if.else:
+  %b = load ptr, ptr %p
+  store ptr %p, ptr %b, align 8, !nontemporal !1
+  br label %if.end
+
+if.end:
+  ret void
+}
 
 !0 = !{}
+!1 = !{i32 1}
diff --git a/llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll b/llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll
--- a/llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll
+++ b/llvm/test/Transforms/SimplifyCFG/X86/sink-common-code.ll
@@ -1559,3 +1559,47 @@
 end:
   ret void
 }
+
+define void @nontemporal(ptr %ptr, i1 %cond) {
+; CHECK-LABEL: @nontemporal(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    store i64 0, ptr [[PTR:%.*]], align 8, !nontemporal !7
+; CHECK-NEXT:    ret void
+;
+entry:
+  br i1 %cond, label %if.then, label %if.else
+
+if.then:
+  store i64 0, ptr %ptr, align 8, !nontemporal !12
+  br label %if.end
+
+if.else:
+  store i64 0, ptr %ptr, align 8, !nontemporal !12
+  br label %if.end
+
+if.end:
+  ret void
+}
+
+define void @nontemporal_mismatch(ptr %ptr, i1 %cond) {
+; CHECK-LABEL: @nontemporal_mismatch(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    store i64 0, ptr [[PTR:%.*]], align 8
+; CHECK-NEXT:    ret void
+;
+entry:
+  br i1 %cond, label %if.then, label %if.else
+
+if.then:
+  store i64 0, ptr %ptr, align 8, !nontemporal !12
+  br label %if.end
+
+if.else:
+  store i64 0, ptr %ptr, align 8
+  br label %if.end
+
+if.end:
+  ret void
+}
+
+!12 = !{i32 1}