1 files changed, 70 insertions, 0 deletions
diff --git a/test/Transforms/Mem2Reg/use-analysis.ll b/test/Transforms/Mem2Reg/use-analysis.ll
new file mode 100644
index 0000000000..b08b1f191b
--- /dev/null
+++ b/test/Transforms/Mem2Reg/use-analysis.ll
@@ -0,0 +1,70 @@
+; RUN: opt -mem2reg -S -o - < %s | FileCheck %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-n8:16:32:64"
+
+declare void @llvm.lifetime.start(i64 %size, i8* nocapture %ptr)
+declare void @llvm.lifetime.end(i64 %size, i8* nocapture %ptr)
+
+define void @test1() {
+; Ensure we can look through a bitcast to i8* and the addition of lifetime
+; markers.
+;
+; CHECK-LABEL: @test1(
+; CHECK-NOT: alloca
+; CHECK: ret void
+
+  %A = alloca i32
+  %B = bitcast i32* %A to i8*
+  call void @llvm.lifetime.start(i64 2, i8* %B)
+  store i32 1, i32* %A
+  call void @llvm.lifetime.end(i64 2, i8* %B)
+  ret void
+}
+
+define void @test2() {
+; Ensure we can look through a GEP to i8* and the addition of lifetime
+; markers.
+;
+; CHECK-LABEL: @test2(
+; CHECK-NOT: alloca
+; CHECK: ret void
+
+  %A = alloca {i8, i16}
+  %B = getelementptr {i8, i16}* %A, i32 0, i32 0
+  call void @llvm.lifetime.start(i64 2, i8* %B)
+  store {i8, i16} zeroinitializer, {i8, i16}* %A
+  call void @llvm.lifetime.end(i64 2, i8* %B)
+  ret void
+}
+
+define i32 @test3(i32 %x) {
+; CHECK-LABEL: @test3(
+;
+; Check that we recursively walk the uses of the alloca and thus can see
+; through round trip bitcasts, dead bitcasts, GEPs, multiple GEPs, and lifetime
+; markers.
+entry:
+  %a = alloca i32
+; CHECK-NOT: alloca
+
+  %b = bitcast i32* %a to i8*
+  %b2 = getelementptr inbounds i8* %b, i32 0
+  %b3 = getelementptr inbounds i8* %b2, i32 0
+  call void @llvm.lifetime.start(i64 -1, i8* %b3)
+; CHECK-NOT: call void @llvm.lifetime.start
+
+  store i32 %x, i32* %a
+; CHECK-NOT: store
+
+  %dead = bitcast i32* %a to i4096*
+  %dead1 = bitcast i4096* %dead to i42*
+  %dead2 = getelementptr inbounds i32* %a, i32 %x
+; CHECK-NOT: bitcast
+; CHECK-NOT: getelementptr
+
+  %ret = load i32* %a
+; CHECK-NOT: load
+
+  ret i32 %ret
+; CHECK: ret i32 %x
+}