[Bug] PTODSL-vmi, abs interface, Incomplete lowering of pmode="merge" causes type-dependent VPTO emission failures

[chenben09]

Component

PTO Dialect / ODS (include/PTO/IR)

Description

在 A5 平台上，使用：
result = pto.vmi.vabs(
source,
mask,
pmode="merge",
)
时，VABS 无法正常完成编译。
当前不同数据类型出现了不同的错误信息：

• 对于 si8、si16、f16、bf16，报 mask granularity mismatch；
• 对于 si32、f32，报 VMI residual operation。

Reproduction (minimal)

@jit_kernel(name, params)
def kernel(src_ptr: pto.ptr(dtype, "gm"), out_ptr: pto.ptr(dtype, "gm")):
    src_ub = pto.castptr(pto.i64(0), pto.ptr(dtype, "ub"))
    out_ub = pto.castptr(pto.i64(nbytes), pto.ptr(dtype, "ub"))
    pto.mte_gm_ub(src_ptr, src_ub, 0, nbytes, nburst=(1, 0, 0))
    pto.set_flag("MTE2", "V", event_id=0)
    pto.wait_flag("MTE2", "V", event_id=0)
    source = pto.vmi.vload(src_ub, pto.const(0, dtype=pto.index), size=vl)
    if masked:
        if mask_kind == "group_prefix":
            predicate = pto.vmi.create_mask(active_lanes, size=vl, group=group)
        else:
            predicate = pto.vmi.create_mask(active_lanes, size=vl)
        result = pto.vmi.vabs(source, predicate, pmode=pmode)
    else:
        result = pto.vmi.vabs(source)
    pto.vmi.vstore(result, out_ub, pto.const(0, dtype=pto.index))
    pto.set_flag("V", "MTE3", event_id=0)
    pto.wait_flag("V", "MTE3", event_id=0)
    pto.mte_ub_gm(out_ub, out_ptr, nbytes, nburst=(1, 0, 0))

参数信息如下：
- `vl = 256`
- `group = 1`
- `mask_kind = "prefix"`
- `active_lanes = 128`
- `masked = true`
- `pmode = "merge"`

Changing only the data type changes the diagnostic:

- `dtype = bf16`: mask granularity mismatch
- `dtype = f32`: residual VMI operation

Expected behavior

编译成功

Actual behavior / error logs

None

Git commit

e32488c

Host platform

Linux (aarch64)

Target Ascend arch (if relevant)

a5

PTOAS build level (if relevant)

None

[mouliangyu]

文档先改成不支持