placeholder sext/zext/trunc elimination pass

CMakeLists.txt

@@ -170,6 +170,7 @@ set(REDREAM_SOURCES
   src/jit/ir/ir_reader.cc
   src/jit/ir/ir_writer.cc
   #src/jit/ir/passes/constant_propagation_pass.cc
+  src/jit/ir/passes/conversion_elimination_pass.cc
   src/jit/ir/passes/dead_code_elimination_pass.cc
   src/jit/ir/passes/load_store_elimination_pass.cc
   src/jit/ir/passes/pass_runner.cc

src/jit/ir/passes/conversion_elimination_pass.cc

@@ -0,0 +1,74 @@
+#include "jit/ir/passes/conversion_elimination_pass.h"
+
+using namespace re::jit::backend;
+using namespace re::jit::ir;
+using namespace re::jit::ir::passes;
+
+DEFINE_STAT(num_sext_removed, "Number of sext eliminated");
+DEFINE_STAT(num_zext_removed, "Number of zext eliminated");
+DEFINE_STAT(num_trunc_removed, "Number of trunc eliminated");
+
+void ConversionEliminationPass::Run(IRBuilder &builder) {
+  auto it = builder.instrs().begin();
+  auto end = builder.instrs().end();
+
+  while (it != end) {
+    Instr *instr = *(it++);
+
+    // eliminate unnecessary sext / zext operations
+    if (instr->op() == OP_LOAD_HOST || instr->op() == OP_LOAD_GUEST ||
+        instr->op() == OP_LOAD_CONTEXT) {
+      ValueType memory_type = VALUE_V;
+      bool same_type = true;
+      bool all_sext = true;
+      bool all_zext = true;
+
+      for (auto use : instr->uses()) {
+        Instr *use_instr = use->instr();
+
+        if (use_instr->op() == OP_SEXT || use_instr->op() == OP_ZEXT) {
+          if (memory_type == VALUE_V) {
+            memory_type = use_instr->type();
+          }
+
+          if (memory_type != use_instr->type()) {
+            same_type = false;
+          }
+        }
+
+        if (use_instr->op() != OP_SEXT) {
+          all_sext = false;
+        }
+
+        if (use_instr->op() != OP_ZEXT) {
+          all_zext = false;
+        }
+      }
+
+      if (same_type && all_sext) {
+        // TODO implement
+
+        num_sext_removed++;
+      } else if (same_type && all_zext) {
+        // TODO implement
+
+        num_zext_removed++;
+      }
+    } else if (instr->op() == OP_STORE_HOST || instr->op() == OP_STORE_GUEST ||
+               instr->op() == OP_STORE_CONTEXT) {
+      Value *store_value = instr->arg1();
+
+      if (!store_value->constant()) {
+        Instr *def = store_value->def();
+
+        if (def->op() == OP_TRUNC) {
+          // TODO implement
+
+          // note, don't actually remove the truncation as other values may
+          // reference it. let DCE clean it up
+          num_trunc_removed++;
+        }
+      }
+    }
+  }
+}

src/jit/ir/passes/conversion_elimination_pass.h

@@ -0,0 +1,23 @@
+#ifndef CONVERSION_ELIMINATION_PASS_H
+#define CONVERSION_ELIMINATION_PASS_H
+
+#include "jit/backend/backend.h"
+#include "jit/ir/passes/pass_runner.h"
+
+namespace re {
+namespace jit {
+namespace ir {
+namespace passes {
+
+class ConversionEliminationPass : public Pass {
+ public:
+  const char *name() { return "cve"; }
+
+  void Run(IRBuilder &builder);
+};
+}
+}
+}
+}
+
+#endif

tools/recc.cc

@@ -7,6 +7,7 @@
 #include "jit/frontend/sh4/sh4_frontend.h"
 #include "jit/ir/ir_builder.h"
 #include "jit/ir/ir_reader.h"
+#include "jit/ir/passes/conversion_elimination_pass.h"
 #include "jit/ir/passes/dead_code_elimination_pass.h"
 #include "jit/ir/passes/load_store_elimination_pass.h"
 #include "sys/filesystem.h"
@@ -16,7 +17,7 @@ using namespace re::jit::ir;
 using namespace re::jit::ir::passes;
 using namespace re::sys;
 
-DEFINE_string(pass, "lse,dce", "Comma-separated list of passes to run");
+DEFINE_string(pass, "lse,cve,dce", "Comma-separated list of passes to run");
 DEFINE_bool(print_after_all, true, "Print IR after each pass");
 DEFINE_bool(stats, true, "Display pass stats");
 
@@ -62,6 +63,8 @@ static void process_file(const char *filename, bool disable_ir_dump) {
 
     if (name == "lse") {
       pass = std::unique_ptr<Pass>(new LoadStoreEliminationPass());
+    } else if (name == "cve") {
+      pass = std::unique_ptr<Pass>(new ConversionEliminationPass());
     } else if (name == "dce") {
       pass = std::unique_ptr<Pass>(new DeadCodeEliminationPass());
     } else {