diff --git a/.circleci/config.yml b/.circleci/config.yml
index c22bc8be..0822ddce 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -65,7 +65,7 @@ commands:
             - go-cache-v2-{{ checksum "go.mod" }}
       - llvm-source-linux
       - run: go install .
-      - run: go test -v ./transform .
+      - run: go test -v ./interp ./transform .
       - run: make gen-device -j4
       - run: make smoketest RISCV=0
       - save_cache:
diff --git a/Makefile b/Makefile
index f55c60e0..156966a7 100644
--- a/Makefile
+++ b/Makefile
@@ -100,7 +100,7 @@ build/tinygo:
 	CGO_CPPFLAGS="$(CGO_CPPFLAGS)" CGO_CXXFLAGS="$(CGO_CXXFLAGS)" CGO_LDFLAGS="$(CGO_LDFLAGS)" $(GO) build -o build/tinygo -tags byollvm .
 
 test:
-	CGO_CPPFLAGS="$(CGO_CPPFLAGS)" CGO_CXXFLAGS="$(CGO_CXXFLAGS)" CGO_LDFLAGS="$(CGO_LDFLAGS)" $(GO) test -v -tags byollvm ./transform .
+	CGO_CPPFLAGS="$(CGO_CPPFLAGS)" CGO_CXXFLAGS="$(CGO_CXXFLAGS)" CGO_LDFLAGS="$(CGO_LDFLAGS)" $(GO) test -v -tags byollvm ./interp ./transform .
 
 tinygo-test:
 	cd tests/tinygotest && tinygo test
diff --git a/interp/interp_test.go b/interp/interp_test.go
new file mode 100644
index 00000000..b9f37e1b
--- /dev/null
+++ b/interp/interp_test.go
@@ -0,0 +1,98 @@
+package interp
+
+import (
+	"io/ioutil"
+	"os"
+	"strings"
+	"testing"
+
+	"tinygo.org/x/go-llvm"
+)
+
+func TestInterp(t *testing.T) {
+	for _, name := range []string{
+		"basic",
+	} {
+		name := name // make tc local to this closure
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+			runTest(t, "testdata/"+name)
+		})
+	}
+}
+
+func runTest(t *testing.T, pathPrefix string) {
+	// Read the input IR.
+	ctx := llvm.NewContext()
+	buf, err := llvm.NewMemoryBufferFromFile(pathPrefix + ".ll")
+	os.Stat(pathPrefix + ".ll") // make sure this file is tracked by `go test` caching
+	if err != nil {
+		t.Fatalf("could not read file %s: %v", pathPrefix+".ll", err)
+	}
+	mod, err := ctx.ParseIR(buf)
+	if err != nil {
+		t.Fatalf("could not load module:\n%v", err)
+	}
+
+	// Perform the transform.
+	err = Run(mod, false)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Run some cleanup passes to get easy-to-read outputs.
+	pm := llvm.NewPassManager()
+	defer pm.Dispose()
+	pm.AddGlobalOptimizerPass()
+	pm.AddDeadStoreEliminationPass()
+	pm.Run(mod)
+
+	// Read the expected output IR.
+	out, err := ioutil.ReadFile(pathPrefix + ".out.ll")
+	if err != nil {
+		t.Fatalf("could not read output file %s: %v", pathPrefix+".out.ll", err)
+	}
+
+	// See whether the transform output matches with the expected output IR.
+	expected := string(out)
+	actual := mod.String()
+	if !fuzzyEqualIR(expected, actual) {
+		t.Logf("output does not match expected output:\n%s", actual)
+		t.Fail()
+	}
+}
+
+// fuzzyEqualIR returns true if the two LLVM IR strings passed in are roughly
+// equal. That means, only relevant lines are compared (excluding comments
+// etc.).
+func fuzzyEqualIR(s1, s2 string) bool {
+	lines1 := filterIrrelevantIRLines(strings.Split(s1, "\n"))
+	lines2 := filterIrrelevantIRLines(strings.Split(s2, "\n"))
+	if len(lines1) != len(lines2) {
+		return false
+	}
+	for i, line := range lines1 {
+		if line != lines2[i] {
+			return false
+		}
+	}
+
+	return true
+}
+
+// filterIrrelevantIRLines removes lines from the input slice of strings that
+// are not relevant in comparing IR. For example, empty lines and comments are
+// stripped out.
+func filterIrrelevantIRLines(lines []string) []string {
+	var out []string
+	for _, line := range lines {
+		if line == "" || line[0] == ';' {
+			continue
+		}
+		if strings.HasPrefix(line, "source_filename = ") {
+			continue
+		}
+		out = append(out, line)
+	}
+	return out
+}
diff --git a/interp/testdata/basic.ll b/interp/testdata/basic.ll
new file mode 100644
index 00000000..8b482c71
--- /dev/null
+++ b/interp/testdata/basic.ll
@@ -0,0 +1,42 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64--linux"
+
+@main.v1 = internal global i64 0
+
+declare void @runtime.printint64(i64) unnamed_addr
+
+declare void @runtime.printnl() unnamed_addr
+
+define void @runtime.initAll() unnamed_addr {
+entry:
+  call void @runtime.init()
+  call void @main.init()
+  ret void
+}
+
+define void @main() unnamed_addr {
+entry:
+  %0 = load i64, i64* @main.v1
+  call void @runtime.printint64(i64 %0)
+  call void @runtime.printnl()
+  ret void
+}
+
+define internal void @runtime.init() unnamed_addr {
+entry:
+  ret void
+}
+
+define internal void @main.init() unnamed_addr {
+entry:
+  store i64 3, i64* @main.v1
+  call void @"main.init#1"()
+  ret void
+}
+
+define internal void @"main.init#1"() unnamed_addr {
+entry:
+  call void @runtime.printint64(i64 5)
+  call void @runtime.printnl()
+  ret void
+}
diff --git a/interp/testdata/basic.out.ll b/interp/testdata/basic.out.ll
new file mode 100644
index 00000000..457a6c2b
--- /dev/null
+++ b/interp/testdata/basic.out.ll
@@ -0,0 +1,20 @@
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64--linux"
+
+declare void @runtime.printint64(i64) unnamed_addr
+
+declare void @runtime.printnl() unnamed_addr
+
+define void @runtime.initAll() unnamed_addr {
+entry:
+  call void @runtime.printint64(i64 5)
+  call void @runtime.printnl()
+  ret void
+}
+
+define void @main() unnamed_addr {
+entry:
+  call void @runtime.printint64(i64 3)
+  call void @runtime.printnl()
+  ret void
+}