encode end-to-end compilation pipeline as a test

tests/BUILD

@@ -6,12 +6,16 @@ filegroup(
     testonly = True,
     data = [
         "//tests:lit.cfg.py",
+        "//tests:poly_to_llvm_main.c",
         "//tools:tutorial-opt",
+        "@llvm-project//clang:clang",
         "@llvm-project//llvm:FileCheck",
         "@llvm-project//llvm:count",
+        "@llvm-project//llvm:llc",
         "@llvm-project//llvm:not",
         "@llvm-project//mlir:mlir-cpu-runner",
         "@llvm-project//mlir:mlir-opt",
+        "@llvm-project//mlir:mlir-translate",
         "@mlir_tutorial_pip_deps_lit//:pkg",
     ],
 )

tests/poly_to_llvm.mlir

@@ -1,6 +1,9 @@
-// RUN: tutorial-opt --poly-to-llvm %s | FileCheck %s
+// RUN: tutorial-opt --poly-to-llvm %s | mlir-translate --mlir-to-llvmir | llc -filetype=obj > %t
+// RUN: clang -c poly_to_llvm_main.c
+// RUN: clang poly_to_llvm_main.o %t -o a.out
+// RUN: ./a.out | FileCheck %s
 
-// CHECK-NOT: poly
+// CHECK: 351
 func.func @test_poly_fn(%arg : i32) -> i32 {
   %tens = tensor.splat %arg : tensor<10xi32>
   %input = poly.from_tensor %tens : tensor<10xi32> -> !poly.poly<10>

tests/poly_to_llvm_main.c

@@ -0,0 +1,12 @@
+#include <stdio.h>
+
+// This is the function we want to call from LLVM
+int test_poly_fn(int x);
+
+int main(int argc, char *argv[]) {
+  int i = 1;
+  int result = test_poly_fn(i);
+  printf("Result: %d\n", result);
+
+  return 0;
+}