Add a comment, add a new testcase

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19179 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 13 insertions, 0 deletions

diff --git a/test/Transforms/DeadStoreElimination/2004-12-28-PartialStore.ll b/test/Transforms/DeadStoreElimination/2004-12-28-PartialStore.ll
index c28e79e554..d9160e5222 100644
--- a/test/Transforms/DeadStoreElimination/2004-12-28-PartialStore.ll
+++ b/test/Transforms/DeadStoreElimination/2004-12-28-PartialStore.ll
@@ -1,5 +1,7 @@
 ; RUN: llvm-as < %s | opt -dse | llvm-dis | grep 'store int 1234567'
 
+; Do not delete stores that are only partially killed.
+
 int %test() {
 	%V = alloca int
 	store int 1234567, int* %V
diff --git a/test/Transforms/DeadStoreElimination/PartialStore.ll b/test/Transforms/DeadStoreElimination/PartialStore.ll
new file mode 100644
index 0000000000..bc8fd3ab6b
--- /dev/null
+++ b/test/Transforms/DeadStoreElimination/PartialStore.ll
@@ -0,0 +1,11 @@
+; RUN: llvm-as < %s | opt -dse | llvm-dis | not grep 'store sbyte'
+; Ensure that the dead store is deleted in this case.  It is wholely
+; overwritten by the second store.
+int %test() {
+	%V = alloca int
+	%V2 = cast int* %V to sbyte*
+	store sbyte 0, sbyte* %V2
+	store int 1234567, int* %V
+	%X = load int* %V
+	ret int %X
+}