[codegen 1.5] Make channel lowering respect placeholders

xls/codegen_v_1_5/BUILD

@@ -41,15 +41,21 @@ cc_library(
     hdrs = ["block_conversion_pass_pipeline.h"],
     deps = [
         ":block_conversion_pass",
+        ":block_conversion_wrapper_pass",
         ":block_finalization_pass",
         ":channel_to_port_io_lowering_pass",
         ":flow_control_insertion_pass",
         ":function_io_lowering_pass",
         ":idle_insertion_pass",
         ":pipeline_register_insertion_pass",
+        ":register_cleanup_pass",
         ":scheduled_block_conversion_pass",
         ":scheduling_pass",
         ":state_to_register_io_lowering_pass",
+        "//xls/passes:dataflow_simplification_pass",
+        "//xls/passes:dce_pass",
+        "//xls/passes:identity_removal_pass",
+        "//xls/passes:optimization_pass",
     ],
 )
 
@@ -93,12 +99,72 @@ cc_test(
     ],
 )
 
+cc_library(
+    name = "register_cleanup_pass",
+    srcs = ["register_cleanup_pass.cc"],
+    hdrs = ["register_cleanup_pass.h"],
+    deps = [
+        ":block_conversion_pass",
+        "//xls/common/status:status_macros",
+        "//xls/data_structures:transitive_closure",
+        "//xls/ir",
+        "//xls/ir:register",
+        "//xls/ir:value",
+        "//xls/ir:value_utils",
+        "//xls/passes:node_dependency_analysis",
+        "//xls/passes:partial_info_query_engine",
+        "//xls/passes:pass_base",
+        "//xls/passes:query_engine",
+        "@com_google_absl//absl/algorithm:container",
+        "@com_google_absl//absl/container:flat_hash_map",
+        "@com_google_absl//absl/container:flat_hash_set",
+        "@com_google_absl//absl/status:statusor",
+        "@com_google_absl//absl/types:span",
+    ],
+)
+
+cc_library(
+    name = "block_conversion_wrapper_pass",
+    srcs = ["block_conversion_wrapper_pass.cc"],
+    hdrs = ["block_conversion_wrapper_pass.h"],
+    deps = [
+        ":block_conversion_pass",
+        "//xls/ir",
+        "//xls/passes:optimization_pass",
+        "//xls/passes:pass_base",
+        "@com_google_absl//absl/status:statusor",
+        "@com_google_absl//absl/strings:str_format",
+        "@com_google_absl//absl/types:span",
+    ],
+)
+
+cc_test(
+    name = "block_conversion_wrapper_pass_test",
+    srcs = ["block_conversion_wrapper_pass_test.cc"],
+    deps = [
+        ":block_conversion_pass",
+        ":block_conversion_wrapper_pass",
+        "//xls/common:xls_gunit_main",
+        "//xls/common/status:matchers",
+        "//xls/ir",
+        "//xls/ir:function_builder",
+        "//xls/ir:ir_matcher",
+        "//xls/ir:ir_test_base",
+        "//xls/passes:dce_pass",
+        "//xls/passes:optimization_pass",
+        "//xls/passes:pass_base",
+        "@com_google_absl//absl/status:statusor",
+        "@googletest//:gtest",
+    ],
+)
+
 cc_library(
     name = "channel_to_port_io_lowering_pass",
     srcs = ["channel_to_port_io_lowering_pass.cc"],
     hdrs = ["channel_to_port_io_lowering_pass.h"],
     deps = [
         ":block_conversion_pass",
+        "//xls/codegen:codegen_options",
         "//xls/codegen:conversion_utils",
         "//xls/codegen:ram_configuration",
         "//xls/common:casts",
@@ -170,6 +236,7 @@ cc_library(
         "//xls/common/status:status_macros",
         "//xls/estimators/delay_model:delay_estimator",
         "//xls/ir",
+        "//xls/passes:optimization_pass",
         "//xls/passes:pass_base",
         "//xls/scheduling:pipeline_schedule_cc_proto",
         "//xls/scheduling:scheduling_options",
@@ -254,9 +321,9 @@ cc_library(
         "//xls/common/status:ret_check",
         "//xls/common/status:status_macros",
         "//xls/ir",
+        "//xls/ir:node_util",
         "//xls/ir:op",
         "//xls/ir:register",
-        "//xls/ir:value",
         "//xls/ir:value_utils",
         "//xls/passes:pass_base",
         "@com_google_absl//absl/algorithm:container",

xls/codegen_v_1_5/block_conversion_pass_pipeline.cc

@@ -20,20 +20,26 @@
 #include <memory>
 
 #include "xls/codegen_v_1_5/block_conversion_pass.h"
+#include "xls/codegen_v_1_5/block_conversion_wrapper_pass.h"
 #include "xls/codegen_v_1_5/block_finalization_pass.h"
 #include "xls/codegen_v_1_5/channel_to_port_io_lowering_pass.h"
 #include "xls/codegen_v_1_5/flow_control_insertion_pass.h"
 #include "xls/codegen_v_1_5/function_io_lowering_pass.h"
 #include "xls/codegen_v_1_5/idle_insertion_pass.h"
 #include "xls/codegen_v_1_5/pipeline_register_insertion_pass.h"
+#include "xls/codegen_v_1_5/register_cleanup_pass.h"
 #include "xls/codegen_v_1_5/scheduled_block_conversion_pass.h"
 #include "xls/codegen_v_1_5/scheduling_pass.h"
 #include "xls/codegen_v_1_5/state_to_register_io_lowering_pass.h"
+#include "xls/passes/dataflow_simplification_pass.h"
+#include "xls/passes/dce_pass.h"
+#include "xls/passes/identity_removal_pass.h"
+#include "xls/passes/optimization_pass.h"
 
 namespace xls::codegen {
 
-std::unique_ptr<BlockConversionCompoundPass>
-CreateBlockConversionPassPipeline() {
+std::unique_ptr<BlockConversionCompoundPass> CreateBlockConversionPassPipeline(
+    OptimizationContext& opt_context) {
   auto top = std::make_unique<BlockConversionCompoundPass>(
       "block_conversion", "Top level codegen v1.5 block conversion pipeline");
 
@@ -64,6 +70,20 @@ CreateBlockConversionPassPipeline() {
   // Lower scheduled block to standard block, inlining each stage.
   top->Add<BlockFinalizationPass>();
 
+  // Clean up unused registers & load-enable bits (including flow-control
+  // registers).
+  top->Add<RegisterCleanupPass>();
+
+  // Clean up identity placeholders and unnecessary array/tuple manipulation.
+  top->Add<BlockConversionWrapperPass>(std::make_unique<IdentityRemovalPass>(),
+                                       opt_context);
+  top->Add<BlockConversionWrapperPass>(
+      std::make_unique<DataflowSimplificationPass>(), opt_context);
+
+  // Remove anything we created & then left dead.
+  top->Add<BlockConversionWrapperPass>(
+      std::make_unique<DeadCodeEliminationPass>(), opt_context);
+
   return top;
 }
 

xls/codegen_v_1_5/block_conversion_pass_pipeline.h

@@ -18,13 +18,14 @@
 #include <memory>
 
 #include "xls/codegen_v_1_5/block_conversion_pass.h"
+#include "xls/passes/optimization_pass.h"
 
 namespace xls::codegen {
 
 // Returns a pipeline which converts an unscheduled IR package into a standard
 // block.
-std::unique_ptr<BlockConversionCompoundPass>
-CreateBlockConversionPassPipeline();
+std::unique_ptr<BlockConversionCompoundPass> CreateBlockConversionPassPipeline(
+    OptimizationContext& opt_context);
 
 }  // namespace xls::codegen