diff --git a/lang/src/compiler/entry/compiler_stageb.hako b/lang/src/compiler/entry/compiler_stageb.hako
index 5613eeb1..24dda570 100644
--- a/lang/src/compiler/entry/compiler_stageb.hako
+++ b/lang/src/compiler/entry/compiler_stageb.hako
@@ -14,6 +14,7 @@ using hako.compiler.entry.bundle_resolver as BundleResolver
 using lang.compiler.parser.box as ParserBox
 using lang.compiler.entry.func_scanner as FuncScannerBox
 using lang.compiler.entry.using_resolver as Stage1UsingResolverBox
+using lang.compiler.builder.mod as CompilerBuilder
 
 // Phase 25.1c: CLI argument → source resolution
 static box StageBArgsBox {
@@ -647,6 +648,26 @@ static box StageBDriverBox {
     // 既定で MIR 直出力は行わない（重い経路を避け、一行出力を保証）。
     local ast_json = p.parse_program2(body_src)
 
+    // 6.3) Apply SSA transformations (CompilerBuilder pipeline)
+    {
+      local trace = env.get("HAKO_COMPILER_BUILDER_TRACE")
+      if trace != null && ("" + trace) == "1" {
+        local preview_len = 200
+        local ajson_len = ("" + ast_json).length()
+        if ajson_len < preview_len { preview_len = ajson_len }
+        print("[compiler-builder] before: " + ("" + ast_json).substring(0, preview_len) + "...")
+      }
+
+      ast_json = CompilerBuilder.apply_all(ast_json)
+
+      if trace != null && ("" + trace) == "1" {
+        local preview_len = 200
+        local ajson_len = ("" + ast_json).length()
+        if ajson_len < preview_len { preview_len = ajson_len }
+        print("[compiler-builder] after: " + ("" + ast_json).substring(0, preview_len) + "...")
+      }
+    }
+
     // 6.5) Dev-toggle: scan for function definitions (static box { method <name>(...) {...} })
     // Toggle: HAKO_STAGEB_FUNC_SCAN
     // Policy:
diff --git a/lang/src/compiler/hako_module.toml b/lang/src/compiler/hako_module.toml
index 2e7460ff..ae4c7c80 100644
--- a/lang/src/compiler/hako_module.toml
+++ b/lang/src/compiler/hako_module.toml
@@ -29,6 +29,7 @@ pipeline_v2.emit_return_box = "pipeline_v2/emit_return_box.hako"
 pipeline_v2.emit_binop_box = "pipeline_v2/emit_binop_box.hako"
 
 # Builder / SSA / Rewrite (scaffolds)
+builder.mod = "builder/mod.hako"
 builder.ssa.local = "builder/ssa/local_ssa.hako"
 builder.ssa.loop = "builder/ssa/loopssa.hako"
 builder.ssa.cond_inserter = "builder/ssa/cond_inserter.hako"
diff --git a/nyash.toml b/nyash.toml
index 48639dee..b42f46bc 100644
--- a/nyash.toml
+++ b/nyash.toml
@@ -121,8 +121,10 @@ path = "lang/src/shared/common/string_helpers.hako"
 "selfhost.shared.json.json_inst_encode_box" = "lang/src/shared/json/json_inst_encode_box.hako"
 "selfhost.shared.common.string_ops" = "lang/src/shared/common/string_ops.hako"
 "lang.compiler.pipeline_v2.using_resolver" = "lang/src/compiler/pipeline_v2/using_resolver_box.hako"
+"lang.compiler.builder.mod" = "lang/src/compiler/builder/mod.hako"
 "lang.compiler.builder.ssa.localvar" = "lang/src/compiler/builder/ssa/local_ssa.hako"
 "lang.compiler.builder.ssa.loop" = "lang/src/compiler/builder/ssa/loopssa.hako"
+"lang.compiler.builder.ssa.loopssa" = "lang/src/compiler/builder/ssa/loopssa.hako"
 "lang.compiler.builder.ssa.cond_inserter" = "lang/src/compiler/builder/ssa/cond_inserter.hako"
 "lang.compiler.builder.rewrite.special" = "lang/src/compiler/builder/rewrite/special.hako"
 "lang.compiler.builder.rewrite.known" = "lang/src/compiler/builder/rewrite/known.hako"