diff --git a/hpvm/tools/hpvm-clang/main.py.in b/hpvm/tools/hpvm-clang/main.py.in
index 57c68ec5d73a78c0441e327cf79b3ec2d6edb5a4..65414803ad58ae0e5a1b1f67318b256b2da64eec 100644
--- a/hpvm/tools/hpvm-clang/main.py.in
+++ b/hpvm/tools/hpvm-clang/main.py.in
@@ -122,7 +122,7 @@ def hpvm_c_to_ll(
         flags.append(f"-std={std}")
     clang = "clang++" if is_cpp else "clang"
     return [
-        str(LLVM_BUILD_BIN / clang), f"-O{optim_level}",
+        str(LLVM_BUILD_BIN / clang), "-O0", "-Xclang", "-disable-O0-optnone", ####   f"-O{optim_level}",
         *includes_s, *flags, *macros,
         "-emit-llvm", "-S", str(src_file), "-o", str(target_file)
     ]
@@ -181,7 +181,9 @@ def _run_opt(
     load_passes_strs = [s for pass_ in pass_names for s in ["-load", f"{pass_}.so"]]
     pass_flags_strs = [f"-{flag}" for flag in pass_flags]
     return [
-        str(LLVM_BUILD_BIN / "opt"), *load_passes_strs, *pass_flags_strs,
+        str(LLVM_BUILD_BIN / "opt"),
+        "-mem2reg",
+        *load_passes_strs, *pass_flags_strs,
         "-S", str(src_file), "-o", str(target_file)
     ]