Index: llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -2186,12 +2186,13 @@
   poisonRedZones(L.ShadowBytes, IRB, ShadowBase, true);
 
   auto UnpoisonStack = [&](IRBuilder<> &IRB) {
+    // Do this always as poisonAlloca can be disabled with
+    // detect_stack_use_after_scope=0.
+    poisonRedZones(L.ShadowBytes, IRB, ShadowBase, false);
     if (HavePoisonedStaticAllocas) {
       // If we poisoned some allocas in llvm.lifetime analysis,
       // unpoison whole stack frame now.
       poisonAlloca(LocalStackBase, LocalStackSize, IRB, false);
-    } else {
-      poisonRedZones(L.ShadowBytes, IRB, ShadowBase, false);
     }
   };
 
Index: llvm/trunk/test/Instrumentation/AddressSanitizer/lifetime-uar-uas.ll
===================================================================
--- llvm/trunk/test/Instrumentation/AddressSanitizer/lifetime-uar-uas.ll
+++ llvm/trunk/test/Instrumentation/AddressSanitizer/lifetime-uar-uas.ll
@@ -28,9 +28,9 @@
   ; CHECK-UAS: call void @__asan_poison_stack_memory(i64 %{{[^ ]+}}, i64 1)
 
   ; Unpoison memory at function exit in UAS mode.
-  ; CHECK-UAS: call void @__asan_unpoison_stack_memory(i64 %{{[^ ]+}}, i64 64)
-  ; CHECK-UAS: ret void
-
+  ; CHECK-UAS: store i64 0
+  ; CHECK-UAS-NEXT: call void @__asan_unpoison_stack_memory(i64 %{{[^ ]+}}, i64 64)
+  ; CHECK-UAS: ret i32 0
   ret i32 0
 }
 
Index: llvm/trunk/test/Instrumentation/AddressSanitizer/lifetime.ll
===================================================================
--- llvm/trunk/test/Instrumentation/AddressSanitizer/lifetime.ll
+++ llvm/trunk/test/Instrumentation/AddressSanitizer/lifetime.ll
@@ -108,7 +108,11 @@
   ; CHECK: __asan_poison_stack_memory
 
   ret void
-  ; CHECK: __asan_unpoison_stack_memory
+  ; CHECK: store i64 0
+  ; CHECK: store i64 0
+  ; CHECK: store i64 0
+  ; CHECK: store i32 0
+  ; CHECK-NEXT: __asan_unpoison_stack_memory
 }
 
 define void @zero_sized(i64 %a) #0 {