[MLIR] Adds a runtime switch to trigger MLIR (#1610)

* [MLIR] Adds a runtime switch to trigger MLIR

Jenkinsfile

@@ -116,9 +116,11 @@ rocmtest clang_debug: rocmnode('vega') { cmake_build ->
     }
 }, mlir_debug: rocmnode('vega') { cmake_build ->
     stage('MLIR Debug') {
-        def sanitizers = "undefined"
-        def debug_flags = "-g -O2 -fsanitize=${sanitizers} -fno-sanitize-recover=${sanitizers}"
-        cmake_build(flags: "-DCMAKE_BUILD_TYPE=debug -DMIGRAPHX_ENABLE_PYTHON=Off -DMIGRAPHX_ENABLE_MLIR=On -DCMAKE_CXX_FLAGS_DEBUG='${debug_flags}' -DCMAKE_C_FLAGS_DEBUG='${debug_flags}'")
+        withEnv(['MIGRAPHX_ENABLE_MLIR=1']) {
+            def sanitizers = "undefined"
+            def debug_flags = "-g -O2 -fsanitize=${sanitizers} -fno-sanitize-recover=${sanitizers}"
+            cmake_build(flags: "-DCMAKE_BUILD_TYPE=debug -DMIGRAPHX_ENABLE_PYTHON=Off -DMIGRAPHX_ENABLE_MLIR=On -DCMAKE_CXX_FLAGS_DEBUG='${debug_flags}' -DCMAKE_C_FLAGS_DEBUG='${debug_flags}'")
+        }
     }
 }, clang_asan: rocmnode('nogpu') { cmake_build ->
     stage('Clang ASAN') {

src/targets/gpu/fuse_mlir.cpp

@@ -27,6 +27,7 @@
 #include <migraphx/pass_manager.hpp>
 #include <migraphx/make_op.hpp>
 #include <migraphx/register_op.hpp>
+#include <migraphx/env.hpp>
 
 namespace migraphx {
 inline namespace MIGRAPHX_INLINE_NS {
@@ -35,6 +36,8 @@ struct module;
 
 namespace gpu {
 
+MIGRAPHX_DECLARE_ENV_VAR(MIGRAPHX_ENABLE_MLIR);
+
 #ifdef MIGRAPHX_MLIR
 struct mlir_conv
 {
@@ -143,7 +146,17 @@ struct find_conv_pointwise
 void fuse_mlir::apply(module_pass_manager& mpm) const
 {
 #ifdef MIGRAPHX_MLIR
-    match::find_matches(mpm, find_conv_pointwise{});
+    const bool mlir_enabled = enabled(MIGRAPHX_ENABLE_MLIR{});
+    if(mlir_enabled)
+    {
+        match::find_matches(mpm, find_conv_pointwise{});
+    }
+    else
+    {
+        std::cerr << "WARNING: MIGraphX built with MLIR but it is not enabled. Please set the env "
+                     "var MIGRAPHX_ENABLE_MLIR to use MLIR kernel generator."
+                  << std::endl;
+    }
 #else
     (void)mpm;
 #endif