[AMD] Avoid unneeded instruction schedule pass runs (#5832)

We only want to run them if an active variant is requested.

third_party/amd/backend/compiler.py

@@ -218,7 +218,8 @@ def make_ttgir(mod, metadata, options):
                                              "equivalent behavior in the past.")
             amd.passes.ttgpuir.add_stream_pipeline(pm, options.num_stages, stream_prefetch)
             passes.common.add_canonicalizer(pm)
-        amd.passes.ttgpuir.insert_instruction_sched_hints(pm)
+        if options.instruction_sched_variant.lower() != "none":
+            amd.passes.ttgpuir.insert_instruction_sched_hints(pm)
         passes.ttgpuir.add_optimize_dot_operands(pm, True)
         passes.ttgpuir.add_remove_layout_conversions(pm)
         passes.ttgpuir.add_reduce_data_duplication(pm)
@@ -274,8 +275,9 @@ def make_llir(src, metadata, options):
         passes.common.add_canonicalizer(pm)
         passes.common.add_cse(pm)
         passes.common.add_symbol_dce(pm)
-        amd.passes.ttgpuir.lower_instruction_sched_hints(pm, options.arch, options.num_stages,
-                                                         options.instruction_sched_variant)
+        if options.instruction_sched_variant.lower() != "none":
+            amd.passes.ttgpuir.lower_instruction_sched_hints(pm, options.arch, options.num_stages,
+                                                             options.instruction_sched_variant)
         if os.environ.get("TRITON_DISABLE_LINE_INFO", "0") == "0":
             passes.llvmir.add_di_scope(pm)
         amd.passes.ttgpuir.add_builtin_func_to_llvmir(pm, __HIP_FTZ)