diff --git a/llvm/test/CodeGen/WebAssembly/loop-idiom.ll b/llvm/test/CodeGen/WebAssembly/loop-idiom.ll
new file mode 100644
index 0000000..2906df2
--- /dev/null
+++ b/llvm/test/CodeGen/WebAssembly/loop-idiom.ll
@@ -0,0 +1,53 @@
+; RUN: opt -loop-idiom -S < %s -march=wasm32 | FileCheck %s
+
+target datalayout = "e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-unknown"
+
+
+; Make sure loop-idiom doesn't create memcpy or memset. These aren't well
+; supported in WebAssembly for now.
+;
+; TODO Check the patterns are recognized once memcpy / memset are supported.
+
+; CHECK-LABEL: @cpy(
+; CHECK-NOT: llvm.memcpy
+; CHECK: load
+; CHECK: store
+define void @cpy(i64 %Size) {
+bb.nph:
+  %Base = alloca i8, i32 10000
+  %Dest = alloca i8, i32 10000
+  br label %for.body
+
+for.body:
+  %indvar = phi i64 [ 0, %bb.nph ], [ %indvar.next, %for.body ]
+  %I.0.014 = getelementptr i8, i8* %Base, i64 %indvar
+  %DestI = getelementptr i8, i8* %Dest, i64 %indvar
+  %V = load i8, i8* %I.0.014, align 1
+  store i8 %V, i8* %DestI, align 1
+  %indvar.next = add i64 %indvar, 1
+  %exitcond = icmp eq i64 %indvar.next, %Size
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}
+
+; CHECK-LABEL: @set(
+; CHECK-NOT: llvm.memset
+; CHECK: store
+define void @set(i8* %Base, i64 %Size) {
+bb.nph:
+  br label %for.body
+
+for.body:
+  %indvar = phi i64 [ 0, %bb.nph ], [ %indvar.next, %for.body ]
+  %I.0.014 = getelementptr i8, i8* %Base, i64 %indvar
+  store i8 0, i8* %I.0.014, align 1
+  %indvar.next = add i64 %indvar, 1
+  %exitcond = icmp eq i64 %indvar.next, %Size
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:
+  ret void
+}