1 files changed, 74 insertions, 0 deletions
diff --git a/llvm/test/Transforms/MemCpyOpt/stackrestore.ll b/llvm/test/Transforms/MemCpyOpt/stackrestore.ll
new file mode 100644
index 00000000000..4bead3381cc
--- /dev/null
+++ b/llvm/test/Transforms/MemCpyOpt/stackrestore.ll
@@ -0,0 +1,74 @@
+; RUN: opt -S -memcpyopt < %s | FileCheck %s
+
+; PR40118: BasicAA didn't realize that stackrestore ends the lifetime of
+; unescaped dynamic allocas, such as those that might come from inalloca.
+
+source_filename = "t.cpp"
+target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
+target triple = "i686-unknown-windows-msvc19.14.26433"
+
+@str = internal constant [9 x i8] c"abcdxxxxx"
+
+
+; Test that we can propagate memcpy through an unescaped dynamic alloca across
+; a call to @external.
+
+define i32 @test_norestore(i32 %n) {
+  %tmpmem = alloca [10 x i8], align 4
+  %tmp = getelementptr inbounds [10 x i8], [10 x i8]* %tmpmem, i32 0, i32 0
+
+  ; Make a dynamic alloca, initialize it.
+  %p = alloca i8, i32 %n, align 4
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %p, i8* align 1 getelementptr inbounds ([9 x i8], [9 x i8]* @str, i32 0, i32 0), i32 9, i1 false)
+
+  ; This extra byte exists to prevent memcpyopt from propagating @str.
+  %p10 = getelementptr inbounds i8, i8* %p, i32 9
+  store i8 0, i8* %p10
+
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %tmp, i8* %p, i32 10, i1 false)
+  call void @external()
+  %heap = call i8* @malloc(i32 9)
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %heap, i8* %tmp, i32 9, i1 false)
+  call void @useit(i8* %heap)
+  ret i32 0
+}
+
+; CHECK-LABEL: define i32 @test_norestore(i32 %n)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %p, i8* align 1 getelementptr inbounds ([9 x i8], [9 x i8]* @str, i32 0, i32 0), i32 9, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %tmp, i8* %p, i32 10, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %heap, i8* %p, i32 9, i1 false)
+
+
+; Do not propagate memcpy from %p across the stackrestore.
+
+define i32 @test_stackrestore() {
+  %tmpmem = alloca [10 x i8], align 4
+  %tmp = getelementptr inbounds [10 x i8], [10 x i8]* %tmpmem, i32 0, i32 0
+  %inalloca.save = tail call i8* @llvm.stacksave()
+  %argmem = alloca inalloca [10 x i8], align 4
+  %p = getelementptr inbounds [10 x i8], [10 x i8]* %argmem, i32 0, i32 0
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %p, i8* align 1 getelementptr inbounds ([9 x i8], [9 x i8]* @str, i32 0, i32 0), i32 9, i1 false)
+
+  ; This extra byte exists to prevent memcpyopt from propagating @str.
+  %p10 = getelementptr inbounds [10 x i8], [10 x i8]* %argmem, i32 0, i32 9
+  store i8 0, i8* %p10
+
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %tmp, i8* %p, i32 10, i1 false)
+  call void @llvm.stackrestore(i8* %inalloca.save)
+  %heap = call i8* @malloc(i32 9)
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %heap, i8* %tmp, i32 9, i1 false)
+  call void @useit(i8* %heap)
+  ret i32 0
+}
+
+; CHECK-LABEL: define i32 @test_stackrestore()
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %p, i8* align 1 getelementptr inbounds ([9 x i8], [9 x i8]* @str, i32 0, i32 0), i32 9, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %tmp, i8* %p, i32 10, i1 false)
+; CHECK: call void @llvm.memcpy.p0i8.p0i8.i32(i8* %heap, i8* %tmp, i32 9, i1 false)
+
+declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture writeonly, i8* nocapture readonly, i32, i1)
+declare i8* @llvm.stacksave()
+declare void @llvm.stackrestore(i8*)
+declare i8* @malloc(i32)
+declare void @useit(i8*)
+declare void @external()