Split tests into two packages in Bazel build.

This separates MLIR tests and regular Enzyme integration tests into independent
packages, making sure only a subset of targets is rebuilt and retested when
requested to decrease overhead.

enzyme/BUILD

@@ -1,7 +1,5 @@
-load("@llvm-project//llvm:lit_test.bzl", "lit_test", "package_path")
 load("@llvm-project//llvm:tblgen.bzl", "gentbl")
 load("@llvm-project//mlir:tblgen.bzl", "gentbl_cc_library", "td_library")
-load("@bazel_skylib//rules:expand_template.bzl", "expand_template")
 
 licenses(["notice"])
 
@@ -633,52 +631,5 @@ cc_binary(
     ],
 )
 
-# Generates lit config input file by applying path placeholder substitutions
-# similar to the configure_lit_site_cfg CMake macro.
-expand_template(
-    name = "lit_site_cfg_py",
-    testonly = True,
-    out = "test/lit.site.cfg.py",
-    substitutions = {
-        "@LLVM_VERSION_MAJOR@": "18",
-        "@LIT_SITE_CFG_IN_HEADER@": "# Autogenerated, do not edit.",
-        "@LLVM_BINARY_DIR@": package_path("@llvm-project//llvm:BUILD"),
-        "@LLVM_TOOLS_BINARY_DIR@": package_path("@llvm-project//llvm:BUILD"),
-        "@LLVM_LIBS_DIR@": package_path("@llvm-project//llvm:BUILD"),
-        "@ENZYME_SOURCE_DIR@": "",
-        "@ENZYME_BINARY_DIR@": "",
-        "@TARGET_TRIPLE@": "",
-        "@TARGETS_TO_BUILD@": "ALL",
-        "@LLVM_SHLIBEXT@": ".so",
-    },
-    template = "test/lit.site.cfg.py.in",
-    visibility = ["//visibility:private"],
-)
-
-[
-    lit_test(
-        name = "%s.test" % src,
-        srcs = [src],
-        data = [
-            ":enzyme-clang",
-            ":enzyme-clang++",
-            ":enzyme-opt",
-            ":enzymemlir-opt",
-            ":test/lit.cfg.py",
-            ":test/lit.site.cfg.py",
-            "@llvm-project//clang:builtin_headers_gen",
-            "@llvm-project//llvm:FileCheck",
-            "@llvm-project//llvm:count",
-            "@llvm-project//llvm:lli",
-            "@llvm-project//llvm:not",
-        ] + glob(["test/**/*.h"]),
-    )
-    for src in glob(
-        [
-            "test/**/*.mlir",
-            "test/Integration/**/*.c",
-            "test/Integration/**/.cpp",
-        ],
-        exclude = ["test/**/*omp*.c"],
-    )
-]
+exports_files(["run_lit.sh"])
+

enzyme/test/BUILD

@@ -0,0 +1,32 @@
+# Enzyme tests.
+
+load("@llvm-project//llvm:lit_test.bzl", "package_path")
+load("@bazel_skylib//rules:expand_template.bzl", "expand_template")
+
+# Generates lit config input file by applying path placeholder substitutions
+# similar to the configure_lit_site_cfg CMake macro.
+expand_template(
+    name = "lit_site_cfg_py",
+    testonly = True,
+    out = "lit.site.cfg.py",
+    substitutions = {
+        "@LLVM_VERSION_MAJOR@": "18",
+        "@LIT_SITE_CFG_IN_HEADER@": "# Autogenerated, do not edit.",
+        "@LLVM_BINARY_DIR@": package_path("@llvm-project//llvm:BUILD"),
+        "@LLVM_TOOLS_BINARY_DIR@": package_path("@llvm-project//llvm:BUILD"),
+        "@LLVM_LIBS_DIR@": package_path("@llvm-project//llvm:BUILD"),
+        "@ENZYME_SOURCE_DIR@": "",
+        "@ENZYME_BINARY_DIR@": "",
+        "@TARGET_TRIPLE@": "",
+        "@TARGETS_TO_BUILD@": "ALL",
+        "@LLVM_SHLIBEXT@": ".so",
+    },
+    template = "lit.site.cfg.py.in",
+    visibility = [":__subpackages__"],
+)
+
+exports_files(
+    ["lit.cfg.py"],
+    visibility = [":__subpackages__"],
+)
+

enzyme/test/Integration/BUILD

@@ -0,0 +1,29 @@
+# Enzyme integration tests.
+
+load("@llvm-project//llvm:lit_test.bzl", "lit_test")
+
+[
+    lit_test(
+        name = "%s.test" % src,
+        srcs = [src],
+        data = [
+            "//:enzyme-clang",
+            "//:enzyme-clang++",
+            "//:enzyme-opt",
+            "//test:lit.cfg.py",
+            "//test:lit.site.cfg.py",
+            "@llvm-project//clang:builtin_headers_gen",
+            "@llvm-project//llvm:FileCheck",
+            "@llvm-project//llvm:count",
+            "@llvm-project//llvm:lli",
+            "@llvm-project//llvm:not",
+        ] + glob(["**/*.h"]),
+    )
+    for src in glob(
+        [
+            "**/*.c",
+            "**/.cpp",
+        ],
+        exclude = ["**/*omp*.c"],
+    )
+]

enzyme/test/MLIR/BUILD

@@ -0,0 +1,25 @@
+# MLIR-specific tests for Enzyme.
+
+load("@llvm-project//llvm:lit_test.bzl", "lit_test")
+
+[
+    lit_test(
+        name = "%s.test" % src,
+        srcs = [src],
+        data = [
+            "//:enzymemlir-opt",
+            "//test:lit.cfg.py",
+            "//test:lit.site.cfg.py",
+            "@llvm-project//clang:builtin_headers_gen",
+            "@llvm-project//llvm:FileCheck",
+            "@llvm-project//llvm:count",
+            "@llvm-project//llvm:lli",
+            "@llvm-project//llvm:not",
+        ] + glob(["**/*.h"]),
+    )
+    for src in glob(
+        [
+            "**/*.mlir",
+        ],
+    )
+]