diff --git a/python/flydsl/expr/primitive.py b/python/flydsl/expr/primitive.py
index 02a60025..20673833 100644
--- a/python/flydsl/expr/primitive.py
+++ b/python/flydsl/expr/primitive.py
@@ -192,6 +192,9 @@ def make_stride(*stride, loc=None, ip=None):
 
 @traced_op
 def make_coord(*coord, loc=None, ip=None):
+    # Support both make_coord(r, c) and make_coord((r, c))
+    if len(coord) == 1 and isinstance(coord[0], tuple):
+        coord = coord[0]
     IntTupleTy, dyncElems = fly.infer_int_tuple_type(coord)
     return fly.make_coord(IntTupleTy, dyncElems, loc=loc, ip=ip)
 
diff --git a/tests/unit/Layout/test_crd2idx.py b/tests/unit/Layout/test_crd2idx.py
new file mode 100644
index 00000000..23edbef3
--- /dev/null
+++ b/tests/unit/Layout/test_crd2idx.py
@@ -0,0 +1,144 @@
+import os
+import subprocess
+import sys
+
+import pytest
+
+import flydsl.compiler as flyc
+import flydsl.expr as fx
+
+
+# --- jit kernels (not collected by pytest due to _run_ prefix) ---
+
+
+@flyc.jit
+def _run_crd2idx_col_major_tuple():
+    """(4,8) col-major with make_coord((r, c)) tuple form"""
+    layout = fx.make_layout((4, 8), (1, 4))
+    for r in range_constexpr(4):
+        for c in range_constexpr(8):
+            idx = fx.crd2idx(fx.make_coord((r, c)), layout)
+            fx.printf("{}", idx)
+
+
+@flyc.jit
+def _run_crd2idx_col_major_varargs():
+    """(4,8) col-major with make_coord(r, c) varargs form"""
+    layout = fx.make_layout((4, 8), (1, 4))
+    for r in range_constexpr(4):
+        for c in range_constexpr(8):
+            idx = fx.crd2idx(fx.make_coord(r, c), layout)
+            fx.printf("{}", idx)
+
+
+@flyc.jit
+def _run_crd2idx_row_major():
+    """(4,8) row-major: idx = r*8 + c"""
+    layout = fx.make_layout((4, 8), (8, 1))
+    for r in range_constexpr(4):
+        for c in range_constexpr(8):
+            idx = fx.crd2idx(fx.make_coord((r, c)), layout)
+            fx.printf("{}", idx)
+
+
+@flyc.jit
+def _run_crd2idx_1d():
+    """1D layout: shape=(8,), stride=(2,)"""
+    layout = fx.make_layout((8,), (2,))
+    for c in range_constexpr(8):
+        idx = fx.crd2idx(fx.make_coord((c,)), layout)
+        fx.printf("{}", idx)
+
+
+@flyc.jit
+def _run_crd2idx_3d():
+    """3D layout: (2,3,4) row-major strides (12,4,1)"""
+    layout = fx.make_layout((2, 3, 4), (12, 4, 1))
+    for i in range_constexpr(2):
+        for j in range_constexpr(3):
+            for k in range_constexpr(4):
+                idx = fx.crd2idx(fx.make_coord((i, j, k)), layout)
+                fx.printf("{}", idx)
+
+
+# --- subprocess helper to capture C-level printf ---
+
+JIT_KERNELS = {
+    "col_major_tuple": _run_crd2idx_col_major_tuple,
+    "col_major_varargs": _run_crd2idx_col_major_varargs,
+    "row_major": _run_crd2idx_row_major,
+    "1d": _run_crd2idx_1d,
+    "3d": _run_crd2idx_3d,
+}
+
+EXPECTED = {
+    "col_major_tuple": [r + 4 * c for r in range(4) for c in range(8)],
+    "col_major_varargs": [r + 4 * c for r in range(4) for c in range(8)],
+    "row_major": [r * 8 + c for r in range(4) for c in range(8)],
+    "1d": [c * 2 for c in range(8)],
+    "3d": [i * 12 + j * 4 + k for i in range(2) for j in range(3) for k in range(4)],
+}
+
+
+def _run_jit_and_capture(test_name):
+    """Run a jit kernel in a subprocess and return parsed int output."""
+    env = os.environ.copy()
+    env["FLYDSL_RUNTIME_ENABLE_CACHE"] = "0"
+    result = subprocess.run(
+        [sys.executable, __file__, "--run", test_name],
+        capture_output=True,
+        text=True,
+        env=env,
+    )
+    assert result.returncode == 0, f"subprocess failed:\n{result.stderr}"
+    lines = [l for l in result.stdout.strip().split("\n") if l.strip()]
+    return [int(x) for x in lines]
+
+
+# --- pytest test cases ---
+
+
+def test_crd2idx_col_major_tuple():
+    """make_coord((r, c)) tuple form works"""
+    actual = _run_jit_and_capture("col_major_tuple")
+    assert actual == EXPECTED["col_major_tuple"]
+
+
+def test_crd2idx_col_major_varargs():
+    """make_coord(r, c) varargs form works"""
+    actual = _run_jit_and_capture("col_major_varargs")
+    assert actual == EXPECTED["col_major_varargs"]
+
+
+def test_crd2idx_col_major_both_forms_equal():
+    """make_coord((r, c)) and make_coord(r, c) produce identical results"""
+    tuple_result = _run_jit_and_capture("col_major_tuple")
+    varargs_result = _run_jit_and_capture("col_major_varargs")
+    assert tuple_result == varargs_result
+
+
+def test_crd2idx_row_major():
+    """(4,8) row-major layout: idx = r*8 + c"""
+    actual = _run_jit_and_capture("row_major")
+    assert actual == EXPECTED["row_major"]
+
+
+def test_crd2idx_1d():
+    """1D layout: shape=(8,), stride=(2,)"""
+    actual = _run_jit_and_capture("1d")
+    assert actual == EXPECTED["1d"]
+
+
+def test_crd2idx_3d():
+    """3D layout: (2,3,4) row-major strides (12,4,1)"""
+    actual = _run_jit_and_capture("3d")
+    assert actual == EXPECTED["3d"]
+
+
+# --- subprocess entry point ---
+
+if __name__ == "__main__":
+    if len(sys.argv) >= 3 and sys.argv[1] == "--run":
+        JIT_KERNELS[sys.argv[2]]()
+    else:
+        pytest.main([__file__, "-v"])