Add W4A8/W4A_FP8 MoE support with groupwise scale

kernels/mfma_preshuffle_pipeline.py

@@ -466,6 +466,277 @@ def lds_load_pack_k32(
     "lds_store_16b_xor16",
     "make_preshuffle_b_layout",
     "load_b_pack_k32",
+    "load_b_raw_w4a16",
+    "unpack_b_w4a16",
+    "load_b_raw_w4a16_groupwise",
+    "unpack_b_w4a16_groupwise",
+    "load_b_raw_w4a8_k64",
+    "load_b_raw_w4a8_groupwise_k64",
+    "unpack_b_w4a8",
+    "unpack_b_w4a_fp8",
     "swizzle_xor16",
     "tile_chunk_coord_i32",
 ]
+
+
+# ---------------------------------------------------------------------------
+# W4A16 groupwise load / unpack helpers
+# ---------------------------------------------------------------------------
+
+def load_b_raw_w4a16_groupwise(
+    buffer_ops,
+    arith,
+    vector,
+    *,
+    arg_b,
+    b_rsrc,
+    layout_b,
+    base_k,
+    ku: int,
+    n_blk,
+    n_intra,
+    lane_div_16,
+    elem_type,
+    scale_rsrc,
+    expert_offset,
+    num_groups: int,
+    group_size: int,
+    n_per_expert: int,
+    kpack_bytes: int = 8,
+):
+    """Phase 1 of W4A16 groupwise B load: buffer_loads for weight + scale.
+
+    Reuses :func:`load_b_raw_w4a16` for the weight load, then issues an
+    additional ``buffer_load_dword`` for the per-group scale.
+
+    Returns ``(packed32, scale_val)``.
+    """
+    packed32 = load_b_raw_w4a16(
+        buffer_ops, arith, vector,
+        arg_b=arg_b, b_rsrc=b_rsrc, layout_b=layout_b,
+        base_k=base_k, ku=ku,
+        n_blk=n_blk, n_intra=n_intra,
+        lane_div_16=lane_div_16, elem_type=elem_type,
+        kpack_bytes=kpack_bytes,
+    )
+
+    i32 = ir.IntegerType.get_signless(32)
+    f32 = ir.F32Type.get()
+
+    c_ku_elems = arith.constant(ku * 32, index=True)
+    k_pos_base = base_k + c_ku_elems
+    c_group_size = arith.constant(group_size, index=True)
+    group_idx = k_pos_base / c_group_size
+
+    c16 = arith.constant(16, index=True)
+    n_global = n_blk * c16 + n_intra
+    c_gm1 = arith.constant(num_groups - 1, index=True)
+    c_npe = arith.constant(n_per_expert, index=True)
+    # n_global is the GLOBAL N index (includes expert offset), so use (G-1)
+    # to compensate: expert_offset*(G-1) + (expert_offset + n_within) = expert_offset*G + n_within
+    scale_idx = expert_offset * c_gm1 + n_global + group_idx * c_npe
+    scale_idx_i32 = arith.index_cast(i32, scale_idx)
+    scale_val = buffer_ops.buffer_load(scale_rsrc, scale_idx_i32, vec_width=1, dtype=f32)
+
+    return (packed32, scale_val)
+
+
+def unpack_b_w4a16_groupwise(packed32, scale_val, arith, vector):
+    """Phase 2 of W4A16 groupwise: unpack + scale + convert to bf16."""
+    return unpack_b_w4a16(packed32, arith, vector, scale_val=scale_val)
+
+
+# ---------------------------------------------------------------------------
+# W4A8 load / unpack helpers (8B K64 loads)
+# ---------------------------------------------------------------------------
+
+def load_b_raw_w4a8_k64(
+    buffer_ops,
+    arith,
+    vector,
+    *,
+    arg_b,
+    b_rsrc,
+    layout_b,
+    base_k,
+    ku: int,
+    n_blk,
+    n_intra,
+    lane_div_16,
+    elem_type,
+    kpack_bytes: int = 8,
+):
+    """Phase 1 of W4A8 per-row B load: 8-byte buffer_load_dwordx2 for one K64 step.
+
+    Loads both K32 halves in a single VMEM instruction (``buffer_load_dwordx2``).
+    Returns ``(packed32_half0, packed32_half1)`` for :func:`unpack_b_w4a8`.
+    """
+    if kpack_bytes != 8:
+        raise ValueError(f"W4A8 requires kpack_bytes=8, got {kpack_bytes!r}")
+
+    c64 = arith.constant(64, index=True)
+    k0_base = base_k / c64
+    k0 = k0_base + arith.constant(ku, index=True)
+    k1 = lane_div_16
+
+    coord_pack = (n_blk, k0, k1, n_intra, arith.constant(0, index=True))
+    idx_pack = crd2idx(coord_pack, layout_b)
+
+    b8 = _buffer_load_vec(
+        buffer_ops, vector, b_rsrc, idx_pack,
+        elem_type=elem_type, vec_elems=8, elem_bytes=1, offset_in_bytes=True,
+    )
+    b_i32x2 = vector.bitcast(T.vec(2, T.i32), b8)
+    half0 = vector.extract(b_i32x2, static_position=[0], dynamic_position=[])
+    half1 = vector.extract(b_i32x2, static_position=[1], dynamic_position=[])
+    return (half0, half1)
+
+
+def load_b_raw_w4a8_groupwise_k64(
+    buffer_ops,
+    arith,
+    vector,
+    *,
+    arg_b,
+    b_rsrc,
+    layout_b,
+    base_k,
+    ku: int,
+    n_blk,
+    n_intra,
+    lane_div_16,
+    elem_type,
+    scale_rsrc,
+    expert_offset,
+    num_groups: int,
+    group_size: int,
+    n_per_expert: int,
+    kpack_bytes: int = 8,
+):
+    """Phase 1 of W4A8 groupwise B load: 8B weight + two scale loads per K64.
+
+    One ``buffer_load_dwordx2`` for both K32 weight halves, plus two
+    ``buffer_load_dword`` for the per-group scales (each K32 half may
+    belong to a different group).
+
+    Returns ``(half0, half1, scale0, scale1)``.
+    """
+    if kpack_bytes != 8:
+        raise ValueError(f"W4A8 requires kpack_bytes=8, got {kpack_bytes!r}")
+
+    i32 = ir.IntegerType.get_signless(32)
+    f32 = ir.F32Type.get()
+
+    c64 = arith.constant(64, index=True)
+    k0_base = base_k / c64
+    k0 = k0_base + arith.constant(ku, index=True)
+    k1 = lane_div_16
+
+    coord_pack = (n_blk, k0, k1, n_intra, arith.constant(0, index=True))
+    idx_pack = crd2idx(coord_pack, layout_b)
+
+    b8 = _buffer_load_vec(
+        buffer_ops, vector, b_rsrc, idx_pack,
+        elem_type=elem_type, vec_elems=8, elem_bytes=1, offset_in_bytes=True,
+    )
+    b_i32x2 = vector.bitcast(T.vec(2, T.i32), b8)
+    half0 = vector.extract(b_i32x2, static_position=[0], dynamic_position=[])
+    half1 = vector.extract(b_i32x2, static_position=[1], dynamic_position=[])
+
+    c16 = arith.constant(16, index=True)
+    n_global = n_blk * c16 + n_intra
+    c_group_size = arith.constant(group_size, index=True)
+    c_gm1 = arith.constant(num_groups - 1, index=True)
+    c_npe = arith.constant(n_per_expert, index=True)
+    # n_global includes expert offset, so use (G-1) to compensate
+    base_scale = expert_offset * c_gm1 + n_global
+
+    k_pos0 = base_k + arith.constant(ku * 2 * 32, index=True)
+    group_idx0 = k_pos0 / c_group_size
+    s0_i32 = arith.index_cast(i32, base_scale + group_idx0 * c_npe)
+    scale0 = buffer_ops.buffer_load(scale_rsrc, s0_i32, vec_width=1, dtype=f32)
+
+    k_pos1 = base_k + arith.constant((ku * 2 + 1) * 32, index=True)
+    group_idx1 = k_pos1 / c_group_size
+    s1_i32 = arith.index_cast(i32, base_scale + group_idx1 * c_npe)
+    scale1 = buffer_ops.buffer_load(scale_rsrc, s1_i32, vec_width=1, dtype=f32)
+
+    return (half0, half1, scale0, scale1)
+
+
+def unpack_b_w4a8(packed32, arith, vector):
+    """Phase 2 of W4A8 B load: 7-op unpack from packed int4 to int8 i64.
+
+    Takes a raw ``packed32`` (one dword of packed int4) and produces one i64
+    value containing 8 signed int8 bytes for one MFMA K32 step.
+    """
+    c_08080808 = arith.constant(0x08080808, type=T.i32)
+    c_0f0f0f0f = arith.constant(0x0F0F0F0F, type=T.i32)
+    c_1e = arith.constant(0x1E, type=T.i32)
+    c_4_i32 = arith.constant(4, type=T.i32)
+
+    s0 = (packed32 & c_08080808) * c_1e
+    even = (packed32 & c_0f0f0f0f) | s0
+
+    t = packed32 >> c_4_i32
+    s1 = (t & c_08080808) * c_1e
+    odd = (t & c_0f0f0f0f) | s1
+
+    v2 = vector.from_elements(T.vec(2, T.i32), [even, odd])
+    v64 = vector.bitcast(T.vec(1, T.i64), v2)
+    return vector.extract(v64, static_position=[0], dynamic_position=[])
+
+
+def unpack_b_w4a_fp8(packed32, arith, vector, rocdl):
+    """Unpack packed int4 (i32) to fp8 i64 for mfma_f32_16x16x32_fp8_fp8.
+
+    Pipeline: int4 -> int8 (7-op unpack) -> f32 (byte extract + sitofp)
+              -> fp8 (cvt_pk_fp8_f32) -> i64.
+    """
+    i32 = ir.IntegerType.get_signless(32)
+    f32 = ir.F32Type.get()
+
+    c_08080808 = arith.constant(0x08080808, type=i32)
+    c_0f0f0f0f = arith.constant(0x0F0F0F0F, type=i32)
+    c_1e = arith.constant(0x1E, type=i32)
+    c_4_i32 = arith.constant(4, type=i32)
+
+    s0 = (packed32 & c_08080808) * c_1e
+    even = (packed32 & c_0f0f0f0f) | s0
+
+    t = packed32 >> c_4_i32
+    s1 = (t & c_08080808) * c_1e
+    odd = (t & c_0f0f0f0f) | s1
+
+    c_8 = arith.constant(8, type=i32)
+    c_16 = arith.constant(16, type=i32)
+    c_24 = arith.constant(24, type=i32)
+
+    from flydsl._mlir.dialects._arith_ops_gen import ShRSIOp as _ShRSIOp
+    _uw = arith._to_raw
+    _av = arith.ArithValue
+
+    def _i32_int8x4_to_fp8x4(val):
+        """Convert i32 containing 4 signed int8 bytes -> i32 containing 4 fp8 bytes."""
+        def _sext_byte(src, shl_amount, shr_amount):
+            shifted = src << shl_amount
+            shrsi_result = _ShRSIOp(_uw(shifted), _uw(shr_amount)).result
+            return _uw(arith.sitofp(f32, _av(shrsi_result)))
+
+        f0 = _sext_byte(val, c_24, c_24)
+        f1 = _sext_byte(val, c_16, c_24)
+        f2 = _sext_byte(val, c_8, c_24)
+        b3 = _ShRSIOp(_uw(val), _uw(c_24)).result
+        f3 = _uw(arith.sitofp(f32, _av(b3)))
+
+        zero = _uw(arith.constant(0, type=i32))
+        pk = rocdl.cvt_pk_fp8_f32(src_a=f0, src_b=f1, old=zero, word_sel=0, res=i32)
+        pk = rocdl.cvt_pk_fp8_f32(src_a=f2, src_b=f3, old=_uw(pk), word_sel=1, res=i32)
+        return pk
+
+    even_fp8 = _i32_int8x4_to_fp8x4(even)
+    odd_fp8 = _i32_int8x4_to_fp8x4(odd)
+
+    v2 = vector.from_elements(T.vec(2, T.i32), [even_fp8, odd_fp8])
+    v64 = vector.bitcast(T.vec(1, T.i64), v2)
+    return vector.extract(v64, static_position=[0], dynamic_position=[])