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Date: Wed, 24 Sep 2025 03:28:24 +0900
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🚀 Phase 15.5 MIR Call統一革命 - LLVM環境変数削除フェーズ完了

## ✅ 完了内容
- **条件分岐実装**: llvm-harness(デフォルト)はLLVM_SYS_180_PREFIX不要
- **後方互換性維持**: llvm-inkwell-legacy使用時はLLVM_SYS_180_PREFIX必要
- **全ツール統一**: 12個のビルドスクリプト・テストスクリプトを一括更新
- **ドキュメント更新**: ENV_VARS.mdでLLVM feature選択方法を明記

## 🛠️ 更新ファイル
- **コアビルド**: src/runner/build.rs, tools/build_llvm.sh, build_llvm.sh
- **スモークテスト**: tools/llvm_smoke.sh, tools/test/smoke/llvm/ir_phi_empty_check.sh
- **CI設定**: .github/workflows/min-gate.yml
- **Windows版**: build_llvm_wsl.sh, build_llvm_wsl_msvc.sh (cross-compilation)
- **開発ツール**: tools/build_compiler_exe.sh, tools/ny_mir_builder.sh
- **ドキュメント**: docs/development/runtime/ENV_VARS.md

## ⚡ 技術的成果
- **環境変数削減**: LLVM_SYS_180_PREFIX → 条件付き使用のみ
- **Python LLVM統合**: llvmliteハーネス経路でRust LLVM依存完全除去
- **ビルド簡略化**: デフォルトでllvm-config-18のみ必要
- **動作確認**: tools/llvm_smoke.sh成功 (1648バイト.oファイル生成)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>
---
 .github/workflows/min-gate.yml              |  7 ++--
 build_llvm.sh                               |  5 ++-
 build_llvm_wsl.sh                           | 17 ++++++---
 build_llvm_wsl_msvc.sh                      | 19 ++++++----
 docs/development/runtime/ENV_VARS.md        |  9 +++--
 src/runner/build.rs                         |  9 +----
 tools/build_compiler_exe.sh                 | 17 ++++++---
 tools/build_llvm.sh                         | 17 ++++++---
 tools/llvm_smoke.sh                         | 21 +++++++----
 tools/ny_mir_builder.sh                     | 40 ++++++++++++++++-----
 tools/test/smoke/llvm/ir_phi_empty_check.sh | 15 +++++---
 tools/test/smoke/selfhost/m2_min/test.sh    | 13 +++++--
 12 files changed, 127 insertions(+), 62 deletions(-)

diff --git a/.github/workflows/min-gate.yml b/.github/workflows/min-gate.yml
index f8b4da66..f95feb6a 100644
--- a/.github/workflows/min-gate.yml
+++ b/.github/workflows/min-gate.yml
@@ -169,11 +169,8 @@ jobs:
       - name: Build (llvm + phi)
         run: |
           set -euo pipefail
-          if command -v llvm-config-18 >/dev/null 2>&1; then
-            LLVM_SYS_180_PREFIX="$(llvm-config-18 --prefix)" cargo build --release --features "llvm,phi-legacy" -q
-          else
-            cargo build --release --features "llvm,phi-legacy" -q
-          fi
+          # llvm feature（llvm-harness）はLLVM_SYS_180_PREFIX不要
+          cargo build --release --features "llvm,phi-legacy" -q
 
       - name: LLVM harness — empty PHI check (batch)
         env:
diff --git a/build_llvm.sh b/build_llvm.sh
index 8ee1588d..2d965e00 100644
--- a/build_llvm.sh
+++ b/build_llvm.sh
@@ -1,6 +1,5 @@
 #!/bin/bash
-# LLVM ビルド - 24スレッド並列
-echo "🚀 LLVM ビルドを開始します..."
-export LLVM_SYS_180_PREFIX=/usr/lib/llvm-18
+# LLVM ビルド - 24スレッド並列（llvmliteハーネス）
+echo "🚀 LLVM ビルド開始（LLVM_SYS_180_PREFIX不要）..."
 cargo build --release --features llvm -j 24
 echo "✅ LLVM ビルド完了！"
\ No newline at end of file
diff --git a/build_llvm_wsl.sh b/build_llvm_wsl.sh
index 4579291b..42b98dfd 100644
--- a/build_llvm_wsl.sh
+++ b/build_llvm_wsl.sh
@@ -3,8 +3,15 @@ set -e
 
 echo "Building Nyash with LLVM for Windows from WSL..."
 
-# Windows側のLLVMを使う
-export LLVM_SYS_180_PREFIX="/mnt/c/Program Files/LLVM"
+# Windows cross-compilation: Use legacy inkwell approach for cross-platform builds
+LLVM_FEATURE=${NYASH_LLVM_FEATURE:-llvm-inkwell-legacy}
+if [[ "$LLVM_FEATURE" == "llvm-inkwell-legacy" ]]; then
+  # Windows側のLLVMを使う (legacy inkwell for cross-compilation)
+  export LLVM_SYS_180_PREFIX="/mnt/c/Program Files/LLVM"
+else
+  echo "Warning: Cross-compilation typically requires llvm-inkwell-legacy feature"
+  echo "Consider setting NYASH_LLVM_FEATURE=llvm-inkwell-legacy for Windows builds"
+fi
 
 # 追加の環境変数（Qt6ビルドで使っていたかもしれない技）
 export LLVM_SYS_180_FFI_WORKAROUND=1
@@ -13,8 +20,8 @@ export CXX=x86_64-w64-mingw32-g++
 export AR=x86_64-w64-mingw32-ar
 
 # MinGWターゲットで試す（Qt6と同じ方法）
-echo "Trying MinGW target..."
-cargo build --target x86_64-pc-windows-gnu --release --features llvm
+echo "Trying MinGW target with feature: $LLVM_FEATURE..."
+cargo build --target x86_64-pc-windows-gnu --release --features "$LLVM_FEATURE"
 
 # 成功したら実行ファイルの場所を表示
 if [ $? -eq 0 ]; then
@@ -22,5 +29,5 @@ if [ $? -eq 0 ]; then
     echo "Binary at: target/x86_64-pc-windows-gnu/release/nyash.exe"
 else
     echo "MinGW build failed, trying MSVC target with cargo-xwin..."
-    cargo xwin build --target x86_64-pc-windows-msvc --release --features llvm
+    cargo xwin build --target x86_64-pc-windows-msvc --release --features "$LLVM_FEATURE"
 fi
\ No newline at end of file
diff --git a/build_llvm_wsl_msvc.sh b/build_llvm_wsl_msvc.sh
index b079deb6..b6f1b24d 100644
--- a/build_llvm_wsl_msvc.sh
+++ b/build_llvm_wsl_msvc.sh
@@ -3,14 +3,21 @@
 
 echo "Setting up Windows cross-compilation with LLVM..."
 
-# Set environment variables for WSL cross-compilation
-export LLVM_SYS_180_PREFIX="C:\\LLVM-18"
-export LLVM_SYS_180_FFI_WORKAROUND="1"
-export LLVM_SYS_NO_LIBFFI="1"  # This is the key!
+# Windows cross-compilation: Use legacy inkwell approach for cross-platform builds
+LLVM_FEATURE=${NYASH_LLVM_FEATURE:-llvm-inkwell-legacy}
+if [[ "$LLVM_FEATURE" == "llvm-inkwell-legacy" ]]; then
+  # Set environment variables for WSL cross-compilation (legacy inkwell)
+  export LLVM_SYS_180_PREFIX="C:\\LLVM-18"
+  export LLVM_SYS_180_FFI_WORKAROUND="1"
+  export LLVM_SYS_NO_LIBFFI="1"  # This is the key!
+else
+  echo "Warning: Cross-compilation typically requires llvm-inkwell-legacy feature"
+  echo "Consider setting NYASH_LLVM_FEATURE=llvm-inkwell-legacy for Windows builds"
+fi
 
 # Use cargo-xwin for cross compilation
-echo "Building nyash.exe for Windows with LLVM support..."
-cargo xwin build --target x86_64-pc-windows-msvc --release --features llvm -j32
+echo "Building nyash.exe for Windows with LLVM support (feature: $LLVM_FEATURE)..."
+cargo xwin build --target x86_64-pc-windows-msvc --release --features "$LLVM_FEATURE" -j32
 
 # Check if successful
 if [ -f "target/x86_64-pc-windows-msvc/release/nyash.exe" ]; then
diff --git a/docs/development/runtime/ENV_VARS.md b/docs/development/runtime/ENV_VARS.md
index 12ae1ab1..1ac2fae6 100644
--- a/docs/development/runtime/ENV_VARS.md
+++ b/docs/development/runtime/ENV_VARS.md
@@ -41,12 +41,17 @@ NYASH_DISABLE_PLUGINS = "1"
 - （今後）タスク/スケジューラ関連の変数は `runtime.*` 名で集約予定
 
 ## LLVM/AOT
-- LLVM_SYS_180_PREFIX: LLVM 18 のパス指定
+- NYASH_LLVM_FEATURE: LLVM機能選択（"llvm"(default) または "llvm-inkwell-legacy"）
+- LLVM_SYS_180_PREFIX: LLVM 18 のパス指定（llvm-inkwell-legacy使用時のみ必要）
 - NYASH_LLVM_VINVOKE_RET_SMOKE, NYASH_LLVM_ARRAY_RET_SMOKE: CI 用スモークトグル
-- NYASH_LLVM_OBJ_OUT: Rust LLVM 経路で生成する `.o` の出力パス（Runner/スクリプトが尊重）
+- NYASH_LLVM_OBJ_OUT: LLVM経路で生成する `.o` の出力パス（Runner/スクリプトが尊重）
 - NYASH_AOT_OBJECT_OUT: AOT パイプラインで使用する `.o` 出力ディレクトリ/パス
 - NYASH_LLVM_USE_HARNESS: "1" で llvmlite ハーネス経路を有効化（MIR(JSON)→Python→.ll→llc→.o）
 
+### LLVM Feature 詳細
+- **llvm** (デフォルト): llvmlite Python ハーネス使用、LLVM_SYS_180_PREFIX不要
+- **llvm-inkwell-legacy**: Rust inkwell bindings使用、LLVM_SYS_180_PREFIX必要
+
 ## 管理方針（提案）
 - コード側: `src/config/env.rs` を単一の集約窓口に（JIT は `jit::config` に委譲）。
 - ドキュメント側: 本ファイルを単一索引にし、用途別に追加。
diff --git a/src/runner/build.rs b/src/runner/build.rs
index 0e30e7fe..62284dbe 100644
--- a/src/runner/build.rs
+++ b/src/runner/build.rs
@@ -148,14 +148,7 @@ pub(super) fn run_build_mvp_impl(runner: &NyashRunner, cfg_path: &str) -> Result
     let _ = std::fs::create_dir_all(&obj_dir);
     let obj_path = obj_dir.join("main.o");
     if aot == "llvm" {
-        if std::env::var("LLVM_SYS_180_PREFIX").ok().is_none()
-            && std::env::var("LLVM_SYS_181_PREFIX").ok().is_none()
-        {
-            return Err(
-                "LLVM 18 not configured. Set LLVM_SYS_180_PREFIX or install LLVM 18 (llvm-config)"
-                    .into(),
-            );
-        }
+        // llvmliteハーネス使用によりLLVM_SYS_180_PREFIX不要
         std::env::set_var("NYASH_LLVM_OBJ_OUT", &obj_path);
         println!("[emit] LLVM object → {}", obj_path.display());
         let status = std::process::Command::new(
diff --git a/tools/build_compiler_exe.sh b/tools/build_compiler_exe.sh
index c26ce2dd..5c968c09 100644
--- a/tools/build_compiler_exe.sh
+++ b/tools/build_compiler_exe.sh
@@ -38,11 +38,18 @@ if ! command -v llvm-config-18 >/dev/null 2>&1; then
   exit 2
 fi
 
-# 1) Build nyash with LLVM harness
-echo "[1/4] Building nyash (LLVM harness) ..."
-_LLVMPREFIX=$(llvm-config-18 --prefix)
-LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
-  cargo build --release -j 24 --features llvm >/dev/null
+# 1) Build nyash with LLVM backend
+LLVM_FEATURE=${NYASH_LLVM_FEATURE:-llvm}
+echo "[1/4] Building nyash (${LLVM_FEATURE}) ..."
+if [[ "$LLVM_FEATURE" == "llvm-inkwell-legacy" ]]; then
+  # Legacy inkwell needs LLVM_SYS_180_PREFIX
+  _LLVMPREFIX=$(llvm-config-18 --prefix)
+  LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
+    cargo build --release -j 24 --features "${LLVM_FEATURE}" >/dev/null
+else
+  # llvm-harness (default) doesn't need LLVM_SYS_180_PREFIX
+  cargo build --release -j 24 --features "${LLVM_FEATURE}" >/dev/null
+fi
 
 # 2) Emit + link compiler.nyash → EXE
 echo "[2/4] Emitting + linking selfhost compiler ..."
diff --git a/tools/build_llvm.sh b/tools/build_llvm.sh
index 74ef89c7..577c9801 100644
--- a/tools/build_llvm.sh
+++ b/tools/build_llvm.sh
@@ -44,12 +44,18 @@ if ! command -v llvm-config-18 >/dev/null 2>&1; then
 fi
 
 echo "[1/4] Building nyash (feature selectable) ..."
-_LLVMPREFIX=$(llvm-config-18 --prefix)
 # Select LLVM feature: default harness (llvm), or legacy inkwell when NYASH_LLVM_FEATURE=llvm-inkwell-legacy
 LLVM_FEATURE=${NYASH_LLVM_FEATURE:-llvm}
 # Use 24 threads for parallel build
-LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
+if [[ "$LLVM_FEATURE" == "llvm-inkwell-legacy" ]]; then
+  # Legacy inkwell需要LLVM_SYS_180_PREFIX
+  _LLVMPREFIX=$(llvm-config-18 --prefix)
+  LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
+    CARGO_INCREMENTAL=1 cargo build --release -j 24 -p nyash-rust --features "$LLVM_FEATURE" >/dev/null
+else
+  # llvm-harness（デフォルト）はLLVM_SYS_180_PREFIX不要
   CARGO_INCREMENTAL=1 cargo build --release -j 24 -p nyash-rust --features "$LLVM_FEATURE" >/dev/null
+fi
 
 echo "[2/4] Emitting object (.o) via LLVM backend ..."
 # Default object output path under target/aot_objects
@@ -100,12 +106,13 @@ if [[ "${NYASH_LLVM_SKIP_EMIT:-0}" != "1" ]]; then
   esac
   if [[ "$COMPILER_MODE" == "harness" ]]; then
     if [[ "${NYASH_LLVM_FEATURE:-llvm}" == "llvm-inkwell-legacy" ]]; then
-      # Legacy path: do not use harness
+      # Legacy path: do not use harness (LLVM_SYS_180_PREFIX needed)
+      _LLVMPREFIX=$(llvm-config-18 --prefix)
       NYASH_LLVM_OBJ_OUT="$OBJ" LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
         ./target/release/nyash --backend llvm "$INPUT" >/dev/null || true
     else
-      # Harness path (Python llvmlite)
-      NYASH_LLVM_OBJ_OUT="$OBJ" NYASH_LLVM_USE_HARNESS=1 LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
+      # Harness path (Python llvmlite - LLVM_SYS_180_PREFIX不要)
+      NYASH_LLVM_OBJ_OUT="$OBJ" NYASH_LLVM_USE_HARNESS=1 \
         ./target/release/nyash --backend llvm "$INPUT" >/dev/null || true
     fi
   fi
diff --git a/tools/llvm_smoke.sh b/tools/llvm_smoke.sh
index bf26d738..e3715a41 100644
--- a/tools/llvm_smoke.sh
+++ b/tools/llvm_smoke.sh
@@ -17,10 +17,18 @@ if ! command -v llvm-config-18 >/dev/null 2>&1; then
   exit 2
 fi
 
-# Resolve LLVM 18 prefix once and export for both 180/181 variants used by llvm-sys
-_LLVMPREFIX=$(llvm-config-18 --prefix)
-export LLVM_SYS_181_PREFIX="${_LLVMPREFIX}"
-export LLVM_SYS_180_PREFIX="${_LLVMPREFIX}"
+# Conditional LLVM prefix setup based on feature
+LLVM_FEATURE=${NYASH_LLVM_FEATURE:-llvm}
+if [[ "$LLVM_FEATURE" == "llvm-inkwell-legacy" ]]; then
+  # Legacy inkwell needs LLVM_SYS_180_PREFIX
+  _LLVMPREFIX=$(llvm-config-18 --prefix)
+  export LLVM_SYS_181_PREFIX="${_LLVMPREFIX}"
+  export LLVM_SYS_180_PREFIX="${_LLVMPREFIX}"
+  echo "[llvm-smoke] Using legacy inkwell with LLVM_SYS_180_PREFIX=${_LLVMPREFIX}" >&2
+else
+  # llvm-harness (default) doesn't need LLVM_SYS_180_PREFIX
+  echo "[llvm-smoke] Using llvm-harness (LLVM_SYS_180_PREFIX not required)" >&2
+fi
 
 # --- AOT smoke: apps/ny-llvm-bitops (bitwise & shift operations) ---
 if [[ "${NYASH_LLVM_BITOPS_SMOKE:-0}" == "1" ]]; then
@@ -41,9 +49,8 @@ else
   echo "[llvm-smoke] skipping ny-llvm-bitops (set NYASH_LLVM_BITOPS_SMOKE=1 to enable)" >&2
 fi
 
-echo "[llvm-smoke] building nyash (${MODE}, feature=llvm)..." >&2
-# Support both llvm-sys 180/181 by exporting both prefixes to the same value
-cargo build -q ${MODE:+--${MODE}} --features llvm
+echo "[llvm-smoke] building nyash (${MODE}, feature=${LLVM_FEATURE})..." >&2
+cargo build -q ${MODE:+--${MODE}} --features "${LLVM_FEATURE}"
 
 echo "[llvm-smoke] running --backend llvm on examples/llvm11_core_smoke.nyash ..." >&2
 rm -f "$OBJ"
diff --git a/tools/ny_mir_builder.sh b/tools/ny_mir_builder.sh
index 5a6c9f78..e5d57f69 100644
--- a/tools/ny_mir_builder.sh
+++ b/tools/ny_mir_builder.sh
@@ -56,9 +56,16 @@ if ! command -v llvm-config-18 >/dev/null 2>&1; then
 fi
 
 # Build nyash + NyRT as needed
-_LLVMPREFIX=$(llvm-config-18 --prefix)
-LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
-  cargo build --release -j 24 --features llvm >/dev/null
+LLVM_FEATURE=${NYASH_LLVM_FEATURE:-llvm}
+if [[ "$LLVM_FEATURE" == "llvm-inkwell-legacy" ]]; then
+  # Legacy inkwell needs LLVM_SYS_180_PREFIX
+  _LLVMPREFIX=$(llvm-config-18 --prefix)
+  LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
+    cargo build --release -j 24 --features "${LLVM_FEATURE}" >/dev/null
+else
+  # llvm-harness (default) doesn't need LLVM_SYS_180_PREFIX
+  cargo build --release -j 24 --features "${LLVM_FEATURE}" >/dev/null
+fi
 if [[ "$EMIT" == "exe" ]]; then
   (cd crates/nyrt && cargo build --release -j 24 >/dev/null)
 fi
@@ -88,8 +95,13 @@ case "$EMIT" in
     export NYASH_LLVM_DUMP_LL=1
     export NYASH_LLVM_LL_OUT="$OUT"
     if [[ "$VERIFY" == "1" ]]; then export NYASH_LLVM_VERIFY=1; fi
-    cat "$IN_FILE" | NYASH_LLVM_USE_HARNESS=1 LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
-      ./target/release/nyash --backend llvm --ny-parser-pipe >/dev/null || true
+    if [[ "$LLVM_FEATURE" == "llvm-inkwell-legacy" ]]; then
+      cat "$IN_FILE" | NYASH_LLVM_USE_HARNESS=1 LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
+        ./target/release/nyash --backend llvm --ny-parser-pipe >/dev/null || true
+    else
+      cat "$IN_FILE" | NYASH_LLVM_USE_HARNESS=1 \
+        ./target/release/nyash --backend llvm --ny-parser-pipe >/dev/null || true
+    fi
     if [[ ! -f "$OUT" ]]; then echo "error: failed to produce $OUT" >&2; exit 4; fi
     [[ "$QUIET" == "0" ]] && echo "OK ll:$OUT"
     ;;
@@ -97,8 +109,13 @@ case "$EMIT" in
     export NYASH_LLVM_OBJ_OUT="$OUT"
     if [[ "$VERIFY" == "1" ]]; then export NYASH_LLVM_VERIFY=1; fi
     rm -f "$OUT"
-    cat "$IN_FILE" | NYASH_LLVM_USE_HARNESS=1 LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
-      ./target/release/nyash --backend llvm --ny-parser-pipe >/dev/null || true
+    if [[ "$LLVM_FEATURE" == "llvm-inkwell-legacy" ]]; then
+      cat "$IN_FILE" | NYASH_LLVM_USE_HARNESS=1 LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
+        ./target/release/nyash --backend llvm --ny-parser-pipe >/dev/null || true
+    else
+      cat "$IN_FILE" | NYASH_LLVM_USE_HARNESS=1 \
+        ./target/release/nyash --backend llvm --ny-parser-pipe >/dev/null || true
+    fi
     if [[ ! -f "$OUT" ]]; then echo "error: failed to produce $OUT" >&2; exit 4; fi
     [[ "$QUIET" == "0" ]] && echo "OK obj:$OUT"
     ;;
@@ -108,8 +125,13 @@ case "$EMIT" in
     export NYASH_LLVM_OBJ_OUT="$OBJ"
     if [[ "$VERIFY" == "1" ]]; then export NYASH_LLVM_VERIFY=1; fi
     rm -f "$OBJ"
-    cat "$IN_FILE" | NYASH_LLVM_USE_HARNESS=1 LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
-      ./target/release/nyash --backend llvm --ny-parser-pipe >/dev/null || true
+    if [[ "$LLVM_FEATURE" == "llvm-inkwell-legacy" ]]; then
+      cat "$IN_FILE" | NYASH_LLVM_USE_HARNESS=1 LLVM_SYS_181_PREFIX="${_LLVMPREFIX}" LLVM_SYS_180_PREFIX="${_LLVMPREFIX}" \
+        ./target/release/nyash --backend llvm --ny-parser-pipe >/dev/null || true
+    else
+      cat "$IN_FILE" | NYASH_LLVM_USE_HARNESS=1 \
+        ./target/release/nyash --backend llvm --ny-parser-pipe >/dev/null || true
+    fi
     if [[ ! -f "$OBJ" ]]; then echo "error: failed to produce object $OBJ" >&2; exit 4; fi
     # Link with NyRT
     NYRT_BASE=${NYRT_DIR:-"$PWD/crates/nyrt"}
diff --git a/tools/test/smoke/llvm/ir_phi_empty_check.sh b/tools/test/smoke/llvm/ir_phi_empty_check.sh
index b8bd8af7..af7e48c5 100644
--- a/tools/test/smoke/llvm/ir_phi_empty_check.sh
+++ b/tools/test/smoke/llvm/ir_phi_empty_check.sh
@@ -7,11 +7,18 @@ set -euo pipefail
 SCRIPT=${1:-apps/tests/loop_if_phi.nyash}
 
 echo "[phi-empty-check] building nyash (llvm features)" >&2
-LLVM_PREFIX=${LLVM_SYS_180_PREFIX:-$(command -v llvm-config-18 >/dev/null 2>&1 && llvm-config-18 --prefix || true)}
-if [[ -n "${LLVM_PREFIX}" ]]; then
-  LLVM_SYS_180_PREFIX="${LLVM_PREFIX}" cargo build --release --features llvm >/dev/null
+LLVM_FEATURE=${NYASH_LLVM_FEATURE:-llvm}
+if [[ "$LLVM_FEATURE" == "llvm-inkwell-legacy" ]]; then
+  # Legacy inkwell needs LLVM_SYS_180_PREFIX
+  LLVM_PREFIX=${LLVM_SYS_180_PREFIX:-$(command -v llvm-config-18 >/dev/null 2>&1 && llvm-config-18 --prefix || true)}
+  if [[ -n "${LLVM_PREFIX}" ]]; then
+    LLVM_SYS_180_PREFIX="${LLVM_PREFIX}" cargo build --release --features "${LLVM_FEATURE}" >/dev/null
+  else
+    cargo build --release --features "${LLVM_FEATURE}" >/dev/null
+  fi
 else
-  cargo build --release --features llvm >/dev/null
+  # llvm-harness (default) doesn't need LLVM_SYS_180_PREFIX
+  cargo build --release --features "${LLVM_FEATURE}" >/dev/null
 fi
 
 IR_OUT=tmp/nyash_harness.ll
diff --git a/tools/test/smoke/selfhost/m2_min/test.sh b/tools/test/smoke/selfhost/m2_min/test.sh
index b84e7f4b..fa91d647 100644
--- a/tools/test/smoke/selfhost/m2_min/test.sh
+++ b/tools/test/smoke/selfhost/m2_min/test.sh
@@ -6,9 +6,16 @@ source "$ROOT/tools/test/lib/shlib.sh"
 
 build_nyash_release
 
-# Skip when LLVM toolchain is not available (either llvm-config-18 or LLVM_SYS_180_PREFIX)
-if ! command -v llvm-config-18 >/dev/null 2>&1 && [[ -z "${LLVM_SYS_180_PREFIX:-}" ]]; then
-  echo "[SKIP] selfhost M2 minimal: LLVM18 not available"; exit 0
+# Skip when LLVM toolchain is not available
+if ! command -v llvm-config-18 >/dev/null 2>&1; then
+  # For llvm-harness (default), we only need llvm-config-18
+  # For llvm-inkwell-legacy, we also need LLVM_SYS_180_PREFIX
+  LLVM_FEATURE=${NYASH_LLVM_FEATURE:-llvm}
+  if [[ "$LLVM_FEATURE" == "llvm-inkwell-legacy" && -z "${LLVM_SYS_180_PREFIX:-}" ]]; then
+    echo "[SKIP] selfhost M2 minimal: LLVM18 not available for legacy inkwell"; exit 0
+  elif [[ "$LLVM_FEATURE" != "llvm-inkwell-legacy" ]]; then
+    echo "[SKIP] selfhost M2 minimal: llvm-config-18 not available"; exit 0
+  fi
 fi
 
 build_ny_llvmc || { echo "[SKIP] selfhost M2 minimal: ny-llvmc not built"; exit 0; }