diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -1605,12 +1605,35 @@
                                  Constant::getNullValue(Int8Ty->getPointerTo()),
                                  IntrinsicI);
       if (MSSAU) {
+        const MemoryUseOrDef *FirstNonDom = nullptr;
+        const auto *AL =
+            MSSAU->getMemorySSA()->getBlockAccesses(IntrinsicI->getParent());
+
+        // If there are accesses in the current basic block, find the first one
+        // that does not come before NewS. The new memory access is inserted
+        // after the found access or before the terminator if no such access is
+        // found.
+        if (AL) {
+          for (auto &Acc : *AL) {
+            if (auto *Current = dyn_cast<MemoryUseOrDef>(&Acc))
+              if (!Current->getMemoryInst()->comesBefore(NewS)) {
+                FirstNonDom = Current;
+                break;
+              }
+          }
+        }
+
         // This added store is to null, so it will never executed and we can
         // just use the LiveOnEntry def as defining access.
-        auto *NewDef = MSSAU->createMemoryAccessInBB(
-            NewS, MSSAU->getMemorySSA()->getLiveOnEntryDef(), NewS->getParent(),
-            MemorySSA::BeforeTerminator);
-        MSSAU->insertDef(cast<MemoryDef>(NewDef), /*RenameUses=*/true);
+        auto *NewDef =
+            FirstNonDom ? MSSAU->createMemoryAccessBefore(
+                              NewS, MSSAU->getMemorySSA()->getLiveOnEntryDef(),
+                              const_cast<MemoryUseOrDef *>(FirstNonDom))
+                        : MSSAU->createMemoryAccessInBB(
+                              NewS, MSSAU->getMemorySSA()->getLiveOnEntryDef(),
+                              NewS->getParent(), MemorySSA::BeforeTerminator);
+
+        MSSAU->insertDef(cast<MemoryDef>(NewDef), /*RenameUses=*/false);
       }
     }
     if (isAssumeWithEmptyBundle(*IntrinsicI))
diff --git a/llvm/test/Transforms/GVN/preserve-memoryssa.ll b/llvm/test/Transforms/GVN/preserve-memoryssa.ll
--- a/llvm/test/Transforms/GVN/preserve-memoryssa.ll
+++ b/llvm/test/Transforms/GVN/preserve-memoryssa.ll
@@ -93,3 +93,56 @@
 for.body.i22:
   ret i32 1
 }
+
+define void @test_assume_false_to_store_undef_1(i32* %ptr) {
+; CHECK-LABEL: @test_assume_false_to_store_undef_1(
+; CHECK-NEXT:    store i32 10, i32* [[PTR:%.*]], align 4
+; CHECK-NEXT:    store i8 undef, i8* null, align 1
+; CHECK-NEXT:    call void @f()
+; CHECK-NEXT:    ret void
+;
+  store i32 10, i32* %ptr
+  %tobool = icmp ne i16 1, 0
+  %xor = xor i1 %tobool, true
+  call void @llvm.assume(i1 %xor)
+  call void @f()
+  ret void
+}
+
+define i32 @test_assume_false_to_store_undef_2(i32* %ptr, i32* %ptr.2) {
+; CHECK-LABEL: @test_assume_false_to_store_undef_2(
+; CHECK-NEXT:    store i32 10, i32* [[PTR:%.*]], align 4
+; CHECK-NEXT:    [[LV:%.*]] = load i32, i32* [[PTR_2:%.*]], align 4
+; CHECK-NEXT:    store i8 undef, i8* null, align 1
+; CHECK-NEXT:    call void @f()
+; CHECK-NEXT:    ret i32 [[LV]]
+;
+  store i32 10, i32* %ptr
+  %lv = load i32, i32* %ptr.2
+  %tobool = icmp ne i16 1, 0
+  %xor = xor i1 %tobool, true
+  call void @llvm.assume(i1 %xor)
+  call void @f()
+  ret i32 %lv
+}
+
+define i32 @test_assume_false_to_store_undef_3(i32* %ptr, i32* %ptr.2) {
+; CHECK-LABEL: @test_assume_false_to_store_undef_3(
+; CHECK-NEXT:    store i32 10, i32* [[PTR:%.*]], align 4
+; CHECK-NEXT:    [[LV:%.*]] = load i32, i32* [[PTR_2:%.*]], align 4
+; CHECK-NEXT:    store i8 undef, i8* null, align 1
+; CHECK-NEXT:    ret i32 [[LV]]
+;
+  store i32 10, i32* %ptr
+  %lv = load i32, i32* %ptr.2
+  %tobool = icmp ne i16 1, 0
+  %xor = xor i1 %tobool, true
+  call void @llvm.assume(i1 %xor)
+  ret i32 %lv
+}
+
+declare void @f()
+
+declare void @llvm.assume(i1 noundef) #0
+
+attributes #0 = { nofree nosync nounwind willreturn }