1 files changed, 51 insertions, 0 deletions
diff --git a/llvm/test/Transforms/DeadStoreElimination/simple.ll b/llvm/test/Transforms/DeadStoreElimination/simple.ll
index 6130fbbf807..604621130e0 100644
--- a/llvm/test/Transforms/DeadStoreElimination/simple.ll
+++ b/llvm/test/Transforms/DeadStoreElimination/simple.ll
@@ -252,6 +252,9 @@ define void @test17v(i8* %P, i8* %Q) nounwind ssp {
 ; Do not delete instruction where possible situation is:
 ; A = B
 ; A = A
+;
+; NB! See PR11763 - currently LLVM allows memcpy's source and destination to be
+; equal (but not inequal and overlapping).
 define void @test18(i8* %P, i8* %Q, i8* %R) nounwind ssp {
   tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i1 false)
   tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %R, i64 12, i1 false)
@@ -521,3 +524,51 @@ define void @test35(i32* noalias %p) {
   store i32 0, i32* %p
   ret void
 }
+
+; We cannot optimize away the first memmove since %P could overlap with %Q.
+define void @test36(i8* %P, i8* %Q) {
+; CHECK-LABEL: @test36(
+; CHECK-NEXT:  tail call void @llvm.memmove.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i1 false)
+; CHECK-NEXT:  tail call void @llvm.memmove.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i1 false)
+; CHECK-NEXT:  ret
+
+  tail call void @llvm.memmove.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i1 false)
+  tail call void @llvm.memmove.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i1 false)
+  ret void
+}
+
+define void @test37(i8* %P, i8* %Q, i8* %R) {
+; CHECK-LABEL: @test37(
+; CHECK-NEXT:  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i1 false)
+; CHECK-NEXT:  tail call void @llvm.memmove.p0i8.p0i8.i64(i8* %P, i8* %R, i64 12, i1 false)
+; CHECK-NEXT:  ret
+
+  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i1 false)
+  tail call void @llvm.memmove.p0i8.p0i8.i64(i8* %P, i8* %R, i64 12, i1 false)
+  ret void
+}
+
+; Same caveat about memcpy as in @test18 applies here.
+define void @test38(i8* %P, i8* %Q, i8* %R) {
+; CHECK-LABEL: @test38(
+; CHECK-NEXT:  tail call void @llvm.memmove.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i1 false)
+; CHECK-NEXT:  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %R, i64 12, i1 false)
+; CHECK-NEXT:  ret
+
+  tail call void @llvm.memmove.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i1 false)
+  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %R, i64 12, i1 false)
+  ret void
+}
+
+define void @test39(i8* %P, i8* %Q, i8* %R) {
+; CHECK-LABEL: @test39(
+; CHECK-NEXT:  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i1 false)
+; CHECK-NEXT:  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %R, i64 8, i1 false)
+; CHECK-NEXT:  ret
+
+  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %Q, i64 12, i1 false)
+  tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* %P, i8* %R, i64 8, i1 false)
+  ret void
+}
+
+declare void @llvm.memmove.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i1)