diff --git a/llvm/test/Instrumentation/AddressSanitizer/fake-stack.ll b/llvm/test/Instrumentation/AddressSanitizer/fake-stack.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Instrumentation/AddressSanitizer/fake-stack.ll
@@ -0,0 +1,224 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -passes='asan-pipeline' -asan-use-after-return=0 -S | FileCheck %s --check-prefixes=CHECK,NEVER
+; RUN: opt < %s -passes='asan-pipeline' -asan-use-after-return=1 -S | FileCheck %s --check-prefixes=CHECK,RUNTIME
+; FIXME: Replace 1->2 in D102462.
+; RUN: opt < %s -passes='asan-pipeline' -asan-use-after-return=1 -S | FileCheck %s --check-prefixes=CHECK,ALWAYS
+target datalayout = "e-i64:64-f80:128-s:64-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+declare void @Foo(i8*)
+
+define void @Empty() uwtable sanitize_address {
+; CHECK-LABEL: @Empty(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    ret void
+;
+entry:
+  ret void
+}
+
+define void @Simple() uwtable sanitize_address {
+; NEVER-LABEL: @Simple(
+; NEVER-NEXT:  entry:
+; NEVER-NEXT:    [[MYALLOCA:%.*]] = alloca i8, i64 64, align 32
+; NEVER-NEXT:    [[TMP0:%.*]] = ptrtoint i8* [[MYALLOCA]] to i64
+; NEVER-NEXT:    [[TMP1:%.*]] = add i64 [[TMP0]], 32
+; NEVER-NEXT:    [[TMP2:%.*]] = inttoptr i64 [[TMP1]] to i8*
+; NEVER-NEXT:    [[TMP3:%.*]] = inttoptr i64 [[TMP0]] to i64*
+; NEVER-NEXT:    store i64 1102416563, i64* [[TMP3]], align 8
+; NEVER-NEXT:    [[TMP4:%.*]] = add i64 [[TMP0]], 8
+; NEVER-NEXT:    [[TMP5:%.*]] = inttoptr i64 [[TMP4]] to i64*
+; NEVER-NEXT:    store i64 ptrtoint ([11 x i8]* @___asan_gen_ to i64), i64* [[TMP5]], align 8
+; NEVER-NEXT:    [[TMP6:%.*]] = add i64 [[TMP0]], 16
+; NEVER-NEXT:    [[TMP7:%.*]] = inttoptr i64 [[TMP6]] to i64*
+; NEVER-NEXT:    store i64 ptrtoint (void ()* @Simple to i64), i64* [[TMP7]], align 8
+; NEVER-NEXT:    [[TMP8:%.*]] = lshr i64 [[TMP0]], 3
+; NEVER-NEXT:    [[TMP9:%.*]] = add i64 [[TMP8]], 2147450880
+; NEVER-NEXT:    [[TMP10:%.*]] = add i64 [[TMP9]], 0
+; NEVER-NEXT:    [[TMP11:%.*]] = inttoptr i64 [[TMP10]] to i64*
+; NEVER-NEXT:    store i64 -868083113472691727, i64* [[TMP11]], align 1
+; NEVER-NEXT:    call void @Foo(i8* [[TMP2]])
+; NEVER-NEXT:    store i64 1172321806, i64* [[TMP3]], align 8
+; NEVER-NEXT:    [[TMP12:%.*]] = add i64 [[TMP9]], 0
+; NEVER-NEXT:    [[TMP13:%.*]] = inttoptr i64 [[TMP12]] to i64*
+; NEVER-NEXT:    store i64 0, i64* [[TMP13]], align 1
+; NEVER-NEXT:    ret void
+;
+; RUNTIME-LABEL: @Simple(
+; RUNTIME-NEXT:  entry:
+; RUNTIME-NEXT:    [[ASAN_LOCAL_STACK_BASE:%.*]] = alloca i64, align 8
+; RUNTIME-NEXT:    [[TMP0:%.*]] = load i32, i32* @__asan_option_detect_stack_use_after_return, align 4
+; RUNTIME-NEXT:    [[TMP1:%.*]] = icmp ne i32 [[TMP0]], 0
+; RUNTIME-NEXT:    br i1 [[TMP1]], label [[TMP2:%.*]], label [[TMP4:%.*]]
+; RUNTIME:       2:
+; RUNTIME-NEXT:    [[TMP3:%.*]] = call i64 @__asan_stack_malloc_0(i64 64)
+; RUNTIME-NEXT:    br label [[TMP4]]
+; RUNTIME:       4:
+; RUNTIME-NEXT:    [[TMP5:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[TMP3]], [[TMP2]] ]
+; RUNTIME-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[TMP5]], 0
+; RUNTIME-NEXT:    br i1 [[TMP6]], label [[TMP7:%.*]], label [[TMP9:%.*]]
+; RUNTIME:       7:
+; RUNTIME-NEXT:    [[MYALLOCA:%.*]] = alloca i8, i64 64, align 32
+; RUNTIME-NEXT:    [[TMP8:%.*]] = ptrtoint i8* [[MYALLOCA]] to i64
+; RUNTIME-NEXT:    br label [[TMP9]]
+; RUNTIME:       9:
+; RUNTIME-NEXT:    [[TMP10:%.*]] = phi i64 [ [[TMP5]], [[TMP4]] ], [ [[TMP8]], [[TMP7]] ]
+; RUNTIME-NEXT:    store i64 [[TMP10]], i64* [[ASAN_LOCAL_STACK_BASE]], align 8
+; RUNTIME-NEXT:    [[TMP11:%.*]] = add i64 [[TMP10]], 32
+; RUNTIME-NEXT:    [[TMP12:%.*]] = inttoptr i64 [[TMP11]] to i8*
+; RUNTIME-NEXT:    [[TMP13:%.*]] = inttoptr i64 [[TMP10]] to i64*
+; RUNTIME-NEXT:    store i64 1102416563, i64* [[TMP13]], align 8
+; RUNTIME-NEXT:    [[TMP14:%.*]] = add i64 [[TMP10]], 8
+; RUNTIME-NEXT:    [[TMP15:%.*]] = inttoptr i64 [[TMP14]] to i64*
+; RUNTIME-NEXT:    store i64 ptrtoint ([11 x i8]* @___asan_gen_ to i64), i64* [[TMP15]], align 8
+; RUNTIME-NEXT:    [[TMP16:%.*]] = add i64 [[TMP10]], 16
+; RUNTIME-NEXT:    [[TMP17:%.*]] = inttoptr i64 [[TMP16]] to i64*
+; RUNTIME-NEXT:    store i64 ptrtoint (void ()* @Simple to i64), i64* [[TMP17]], align 8
+; RUNTIME-NEXT:    [[TMP18:%.*]] = lshr i64 [[TMP10]], 3
+; RUNTIME-NEXT:    [[TMP19:%.*]] = add i64 [[TMP18]], 2147450880
+; RUNTIME-NEXT:    [[TMP20:%.*]] = add i64 [[TMP19]], 0
+; RUNTIME-NEXT:    [[TMP21:%.*]] = inttoptr i64 [[TMP20]] to i64*
+; RUNTIME-NEXT:    store i64 -868083113472691727, i64* [[TMP21]], align 1
+; RUNTIME-NEXT:    call void @Foo(i8* [[TMP12]])
+; RUNTIME-NEXT:    store i64 1172321806, i64* [[TMP13]], align 8
+; RUNTIME-NEXT:    [[TMP22:%.*]] = icmp ne i64 [[TMP5]], 0
+; RUNTIME-NEXT:    br i1 [[TMP22]], label [[TMP23:%.*]], label [[TMP30:%.*]]
+; RUNTIME:       23:
+; RUNTIME-NEXT:    [[TMP24:%.*]] = add i64 [[TMP19]], 0
+; RUNTIME-NEXT:    [[TMP25:%.*]] = inttoptr i64 [[TMP24]] to i64*
+; RUNTIME-NEXT:    store i64 -723401728380766731, i64* [[TMP25]], align 1
+; RUNTIME-NEXT:    [[TMP26:%.*]] = add i64 [[TMP5]], 56
+; RUNTIME-NEXT:    [[TMP27:%.*]] = inttoptr i64 [[TMP26]] to i64*
+; RUNTIME-NEXT:    [[TMP28:%.*]] = load i64, i64* [[TMP27]], align 8
+; RUNTIME-NEXT:    [[TMP29:%.*]] = inttoptr i64 [[TMP28]] to i8*
+; RUNTIME-NEXT:    store i8 0, i8* [[TMP29]], align 1
+; RUNTIME-NEXT:    br label [[TMP33:%.*]]
+; RUNTIME:       30:
+; RUNTIME-NEXT:    [[TMP31:%.*]] = add i64 [[TMP19]], 0
+; RUNTIME-NEXT:    [[TMP32:%.*]] = inttoptr i64 [[TMP31]] to i64*
+; RUNTIME-NEXT:    store i64 0, i64* [[TMP32]], align 1
+; RUNTIME-NEXT:    br label [[TMP33]]
+; RUNTIME:       33:
+; RUNTIME-NEXT:    ret void
+;
+; ALWAYS-LABEL: @Simple(
+; ALWAYS-NEXT:  entry:
+; ALWAYS-NEXT:    [[ASAN_LOCAL_STACK_BASE:%.*]] = alloca i64, align 8
+; ALWAYS-NEXT:    [[TMP0:%.*]] = load i32, i32* @__asan_option_detect_stack_use_after_return, align 4
+; ALWAYS-NEXT:    [[TMP1:%.*]] = icmp ne i32 [[TMP0]], 0
+; ALWAYS-NEXT:    br i1 [[TMP1]], label [[TMP2:%.*]], label [[TMP4:%.*]]
+; ALWAYS:       2:
+; ALWAYS-NEXT:    [[TMP3:%.*]] = call i64 @__asan_stack_malloc_0(i64 64)
+; ALWAYS-NEXT:    br label [[TMP4]]
+; ALWAYS:       4:
+; ALWAYS-NEXT:    [[TMP5:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[TMP3]], [[TMP2]] ]
+; ALWAYS-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[TMP5]], 0
+; ALWAYS-NEXT:    br i1 [[TMP6]], label [[TMP7:%.*]], label [[TMP9:%.*]]
+; ALWAYS:       7:
+; ALWAYS-NEXT:    [[MYALLOCA:%.*]] = alloca i8, i64 64, align 32
+; ALWAYS-NEXT:    [[TMP8:%.*]] = ptrtoint i8* [[MYALLOCA]] to i64
+; ALWAYS-NEXT:    br label [[TMP9]]
+; ALWAYS:       9:
+; ALWAYS-NEXT:    [[TMP10:%.*]] = phi i64 [ [[TMP5]], [[TMP4]] ], [ [[TMP8]], [[TMP7]] ]
+; ALWAYS-NEXT:    store i64 [[TMP10]], i64* [[ASAN_LOCAL_STACK_BASE]], align 8
+; ALWAYS-NEXT:    [[TMP11:%.*]] = add i64 [[TMP10]], 32
+; ALWAYS-NEXT:    [[TMP12:%.*]] = inttoptr i64 [[TMP11]] to i8*
+; ALWAYS-NEXT:    [[TMP13:%.*]] = inttoptr i64 [[TMP10]] to i64*
+; ALWAYS-NEXT:    store i64 1102416563, i64* [[TMP13]], align 8
+; ALWAYS-NEXT:    [[TMP14:%.*]] = add i64 [[TMP10]], 8
+; ALWAYS-NEXT:    [[TMP15:%.*]] = inttoptr i64 [[TMP14]] to i64*
+; ALWAYS-NEXT:    store i64 ptrtoint ([11 x i8]* @___asan_gen_ to i64), i64* [[TMP15]], align 8
+; ALWAYS-NEXT:    [[TMP16:%.*]] = add i64 [[TMP10]], 16
+; ALWAYS-NEXT:    [[TMP17:%.*]] = inttoptr i64 [[TMP16]] to i64*
+; ALWAYS-NEXT:    store i64 ptrtoint (void ()* @Simple to i64), i64* [[TMP17]], align 8
+; ALWAYS-NEXT:    [[TMP18:%.*]] = lshr i64 [[TMP10]], 3
+; ALWAYS-NEXT:    [[TMP19:%.*]] = add i64 [[TMP18]], 2147450880
+; ALWAYS-NEXT:    [[TMP20:%.*]] = add i64 [[TMP19]], 0
+; ALWAYS-NEXT:    [[TMP21:%.*]] = inttoptr i64 [[TMP20]] to i64*
+; ALWAYS-NEXT:    store i64 -868083113472691727, i64* [[TMP21]], align 1
+; ALWAYS-NEXT:    call void @Foo(i8* [[TMP12]])
+; ALWAYS-NEXT:    store i64 1172321806, i64* [[TMP13]], align 8
+; ALWAYS-NEXT:    [[TMP22:%.*]] = icmp ne i64 [[TMP5]], 0
+; ALWAYS-NEXT:    br i1 [[TMP22]], label [[TMP23:%.*]], label [[TMP30:%.*]]
+; ALWAYS:       23:
+; ALWAYS-NEXT:    [[TMP24:%.*]] = add i64 [[TMP19]], 0
+; ALWAYS-NEXT:    [[TMP25:%.*]] = inttoptr i64 [[TMP24]] to i64*
+; ALWAYS-NEXT:    store i64 -723401728380766731, i64* [[TMP25]], align 1
+; ALWAYS-NEXT:    [[TMP26:%.*]] = add i64 [[TMP5]], 56
+; ALWAYS-NEXT:    [[TMP27:%.*]] = inttoptr i64 [[TMP26]] to i64*
+; ALWAYS-NEXT:    [[TMP28:%.*]] = load i64, i64* [[TMP27]], align 8
+; ALWAYS-NEXT:    [[TMP29:%.*]] = inttoptr i64 [[TMP28]] to i8*
+; ALWAYS-NEXT:    store i8 0, i8* [[TMP29]], align 1
+; ALWAYS-NEXT:    br label [[TMP33:%.*]]
+; ALWAYS:       30:
+; ALWAYS-NEXT:    [[TMP31:%.*]] = add i64 [[TMP19]], 0
+; ALWAYS-NEXT:    [[TMP32:%.*]] = inttoptr i64 [[TMP31]] to i64*
+; ALWAYS-NEXT:    store i64 0, i64* [[TMP32]], align 1
+; ALWAYS-NEXT:    br label [[TMP33]]
+; ALWAYS:       33:
+; ALWAYS-NEXT:    ret void
+;
+entry:
+  %x = alloca i8, align 16
+  call void @Foo(i8* %x)
+  ret void
+}
+
+define void @Huge() uwtable sanitize_address {
+; CHECK-LABEL: @Huge(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[MYALLOCA:%.*]] = alloca i8, i64 100288, align 32
+; CHECK-NEXT:    [[TMP0:%.*]] = ptrtoint i8* [[MYALLOCA]] to i64
+; CHECK-NEXT:    [[TMP1:%.*]] = add i64 [[TMP0]], 32
+; CHECK-NEXT:    [[TMP2:%.*]] = inttoptr i64 [[TMP1]] to [100000 x i8]*
+; CHECK-NEXT:    [[TMP3:%.*]] = inttoptr i64 [[TMP0]] to i64*
+; CHECK-NEXT:    store i64 1102416563, i64* [[TMP3]], align 8
+; CHECK-NEXT:    [[TMP4:%.*]] = add i64 [[TMP0]], 8
+; CHECK-NEXT:    [[TMP5:%.*]] = inttoptr i64 [[TMP4]] to i64*
+; CHECK-NEXT:    store i64 ptrtoint ([16 x i8]* @___asan_gen_.1 to i64), i64* [[TMP5]], align 8
+; CHECK-NEXT:    [[TMP6:%.*]] = add i64 [[TMP0]], 16
+; CHECK-NEXT:    [[TMP7:%.*]] = inttoptr i64 [[TMP6]] to i64*
+; CHECK-NEXT:    store i64 ptrtoint (void ()* @Huge to i64), i64* [[TMP7]], align 8
+; CHECK-NEXT:    [[TMP8:%.*]] = lshr i64 [[TMP0]], 3
+; CHECK-NEXT:    [[TMP9:%.*]] = add i64 [[TMP8]], 2147450880
+; CHECK-NEXT:    [[TMP10:%.*]] = add i64 [[TMP9]], 0
+; CHECK-NEXT:    [[TMP11:%.*]] = inttoptr i64 [[TMP10]] to i32*
+; CHECK-NEXT:    store i32 -235802127, i32* [[TMP11]], align 1
+; CHECK-NEXT:    [[TMP12:%.*]] = add i64 [[TMP9]], 12504
+; CHECK-NEXT:    [[TMP13:%.*]] = inttoptr i64 [[TMP12]] to i64*
+; CHECK-NEXT:    store i64 -868082074056920077, i64* [[TMP13]], align 1
+; CHECK-NEXT:    [[TMP14:%.*]] = add i64 [[TMP9]], 12512
+; CHECK-NEXT:    [[TMP15:%.*]] = inttoptr i64 [[TMP14]] to i64*
+; CHECK-NEXT:    store i64 -868082074056920077, i64* [[TMP15]], align 1
+; CHECK-NEXT:    [[TMP16:%.*]] = add i64 [[TMP9]], 12520
+; CHECK-NEXT:    [[TMP17:%.*]] = inttoptr i64 [[TMP16]] to i64*
+; CHECK-NEXT:    store i64 -868082074056920077, i64* [[TMP17]], align 1
+; CHECK-NEXT:    [[TMP18:%.*]] = add i64 [[TMP9]], 12528
+; CHECK-NEXT:    [[TMP19:%.*]] = inttoptr i64 [[TMP18]] to i64*
+; CHECK-NEXT:    store i64 -868082074056920077, i64* [[TMP19]], align 1
+; CHECK-NEXT:    [[XX:%.*]] = getelementptr inbounds [100000 x i8], [100000 x i8]* [[TMP2]], i64 0, i64 0
+; CHECK-NEXT:    call void @Foo(i8* [[XX]])
+; CHECK-NEXT:    store i64 1172321806, i64* [[TMP3]], align 8
+; CHECK-NEXT:    [[TMP20:%.*]] = add i64 [[TMP9]], 0
+; CHECK-NEXT:    [[TMP21:%.*]] = inttoptr i64 [[TMP20]] to i32*
+; CHECK-NEXT:    store i32 0, i32* [[TMP21]], align 1
+; CHECK-NEXT:    [[TMP22:%.*]] = add i64 [[TMP9]], 12504
+; CHECK-NEXT:    [[TMP23:%.*]] = inttoptr i64 [[TMP22]] to i64*
+; CHECK-NEXT:    store i64 0, i64* [[TMP23]], align 1
+; CHECK-NEXT:    [[TMP24:%.*]] = add i64 [[TMP9]], 12512
+; CHECK-NEXT:    [[TMP25:%.*]] = inttoptr i64 [[TMP24]] to i64*
+; CHECK-NEXT:    store i64 0, i64* [[TMP25]], align 1
+; CHECK-NEXT:    [[TMP26:%.*]] = add i64 [[TMP9]], 12520
+; CHECK-NEXT:    [[TMP27:%.*]] = inttoptr i64 [[TMP26]] to i64*
+; CHECK-NEXT:    store i64 0, i64* [[TMP27]], align 1
+; CHECK-NEXT:    [[TMP28:%.*]] = add i64 [[TMP9]], 12528
+; CHECK-NEXT:    [[TMP29:%.*]] = inttoptr i64 [[TMP28]] to i64*
+; CHECK-NEXT:    store i64 0, i64* [[TMP29]], align 1
+; CHECK-NEXT:    ret void
+;
+entry:
+  %x = alloca [100000 x i8], align 16
+  %xx = getelementptr inbounds [100000 x i8], [100000 x i8]* %x, i64 0, i64 0
+  call void @Foo(i8* %xx)
+  ret void
+}