[Feature] ptoas支持从ir到cpp文件变量名变不变，同时需要保留 SSA name hint。

[xig514]

Summary

1. ptoas在level3模式下，cpp文件中变量名的序号和.pto文件不一致，导致定位的时候容易看错，具体可以附件中的txt(txt就是pto文件，改一下扩展名）和cpp文件
2. ptoas是否可以支持SSA name hint，这样在ir中可以携带前端python的变量名，方便问题定位，不然代码中大量的vXXX，不可读。

Motivation / use case

可维可测、易用性提升

kernel.cpp
kernel.txt

Proposed API / behavior

No response

Alternatives considered

No response

Additional context

No response

[zhangqi-chen]

+1 — this feature would significantly help with in-kernel performance debugging.

When triaging per-op latency / pipeline stalls in the generated cpp, mapping a hot line back to its original source variable (gate / up / scale_col / sigmoid / silu / gated / ...) is currently a manual cross-reference between the cpp and the .pto. Preserving source names (or at least an SSA name hint comment) would let us identify the responsible tile and source-level operation directly from the cpp, which is the form we actually profile and read assembly against.

Concrete recent example: build_output/jit_moe_expert_test*/ptoas/exp_swiglu.cpp uses v1..v40 with no semantic info, while the corresponding exp_swiglu.pto already retains names like %gate_2d_v1_inline30__tile, %sigmoid_inline13__tile, %silu_inline4__tile. Propagating those names (or emitting them as comments) into the cpp would make in-kernel perf analysis substantially faster.

[HecreReed]

可以支持前端向 PTO IR 传递可选的变量名提示信息，不过不保证输入 .pto 中的 %v37 在输出 .cpp 中仍然严格叫 v37