perf(vmi): optimize carrier-preserving integer casts

[mouliangyu]

背景

部分整数 cast 只改变逻辑元素解释，不需要执行实际的 vcvt：

• NOSAT narrowing 的 contiguous -> lane_stride=2/4 可以直接复用物理 carrier。
• 当 unsigned widening 的输入已经是 lane_stride=2/4，且 carrier gap 中的高位已知为 0 时，vcvt EVEN/P0 也是冗余的。

仅凭 lane-stride layout 不能推断 gap 为 0，因此 widening 优化采用保守且单一的准入规则：只接受由 canonical zero-filling producer 构造的 carrier，不追踪普通计算的数据流。

修改

• 对 u16/u32 -> u8/u16 的 NOSAT 2x/4x narrowing 直接复用或 bitcast source carrier；SAT narrowing 继续生成 vcvt。
• VMI lowering 对 dense lane-stride narrowing 只分类一次，再按 NOSAT carrier forwarding 或 SAT vcvt emission 选择策略。
• VPTOOptimizeVcvt 由独立的 part 规范化与 zero-gap extension folding patterns 组成，通过 greedy rewrite driver 执行；cast 形状匹配与 producer provenance 分层处理。
• 新增 VPTOOptimizeVcvt pass，识别以下 unsigned zero-gap widening：
  • u8 lane_stride=2 -> u16 contiguous
  • u16 lane_stride=2 -> u32 contiguous
  • u8 lane_stride=4 -> u32 contiguous
• widening 消除统一通过 isCanonicalZeroGapCarrier 准入，只接受：
  • vlds UNPK_B8/UNPK_B16/UNPK4
  • vzunpack 链
  • 对齐的真实 narrowing vcvt（2x 使用 EVEN，4x 使用 P0）
• 普通算术、常量、广播和其他未知来源不参与 provenance 推导，即使某组特定输入可能恰好保持 zero gap。
• 要求全 mask、无 rnd/sat，并要求 2x widening 使用 EVEN、4x widening 使用 P0。
• unknown-gap 输入、signed extension、非全 mask 和错误 part 均保留 vcvt。
• 保持现有 layout assignment 的 lane_stride -> contiguous cast 关系，使一物理 chunk 的 load-extension-store 能自然选择 zero-fill unpack load。

测试

• 新增 surface VMI 端到端 lit，确认三种 widening 分别生成 UNPK_B8、UNPK_B16、UNPK4 load，且不含 vcvt/vzunpack。
• 新增 VPTO provenance 正负向测试，覆盖 unpack load、vzunpack 链、真实 narrowing vcvt、unknown gap、signed、mask 和 part 条件。
• narrowing vcvt 正向覆盖 u16 -> u8 -> u16、u32 -> u8 -> u32；错误的 ODD part 不建立 aligned zero gap。
• integer cast SIM runtime 覆盖 unsigned/signed 8/16/32-bit extension、SAT/NOSAT narrowing，以及三种 zero-gap widening。

验证

• cmake --build build --target PTOASPythonCore pto-test-opt -j4
• llvm-lit -sv -j 32 build/test/lit/vmi_new：446/446 passed
• focused integer-cast/VPTO lit：9/9 passed
• dav_3510 simulator：7 个 kernel、23 个 buffer 与 golden 精确一致
• 最新 focused lit：vpto_optimize_vcvt、vmi_zero_gap_extui_load、vmi_lane_stride_dense_load_store，3/3 passed
• git diff --check

Relates to #1024.

[reedhecre]

A5 板测成功

• 触发方式：merged
• 源码提交：a79b90d32d2c
• 结果汇总：OK 21 / FAIL 0 / SKIP 0
• 日志：/root/ptoas-board-monitor-a5/logs/20260803_220806_merged_pr1077.log
• 结果 TSV：/root/ptoas-board-monitor-a5/logs/20260803_220806_merged_pr1077.tsv

[reedhecre]

A3 板测失败

• 触发方式：merged
• 源码提交：a79b90d32d2c
• 结果汇总：OK 218 / FAIL 2 / SKIP 3
• 日志：/home/zhongxuan/ptoas-board-monitor/runtime/logs/20260803_071139_merged_pr1077.log
• 失败阶段：board-validation / exit=1

失败用例

• comm_p2p_binding_variants (run, exit=1)
• comm_p2p (run, exit=1)

[reedhecre]

A3 板测失败详情：PR #1077

comm_p2p_binding_variants

stage=run info=exit=1

[ERROR] aclrtSynchronizeStream(stream) failed: 507035 (/home/zhongxuan/ptoas-board-monitor/runtime/runs/20260803_071139_merged_pr1077/npu_validation/CommSync/comm_p2p_binding_variants/main.cpp:122)
[ERROR] RecentErrMsg: EZ9999: Inner Error!
EZ9999[PID: 3580661] 2026-08-03-07:45:38.861.135 (EZ9999):  The error from device(chipId:0, dieId:1), serial number is 2537, there is an exception of aivec error, core id is 11, error code = 0x10, dump info: pc start: 0x124200000000, current: 0x124200000164, vec error info: 0x4000000b7, mte error info: 0x6000099, ifu error info: 0x212c0d6200800, ccu error info: 0x40e008000000004f, cube error info: 0, biu error info: 0, aic error mask: 0x6500020bd00028c, para base: 0x12c100000000.[FUNC:PrintCoreInfo][FILE:device_error_core_proc.cc][LINE:645]
        TraceBack (most recent call last):
       The extend info: errcode:(0x10, 0, 0) errorStr: Illegal instruction, which is usually caused by unaligned UUB addresses. fixp_error0 info: 0x6000099, fixp_error1 info: 0, fsmId:1, tslot:6, thread:0, ctxid:0, blk:0, sublk:0, subErrType:4.[FUNC:PrintCoreInfo][FILE:device_error_core_proc.cc][LINE:658]
       Kernel task happen error, retCode=0x31, [vector core exception].[FUNC:PreCheckTaskErr][FILE:davinci_kernel_task.cc][LINE:1729]
       AIV Kernel happen error, retCode=0x31.[FUNC:GetError][FILE:stream.cc][LINE:1475]
       [AIC_INFO] after execute:args print end[FUNC:GetError][FILE:stream.cc][LINE:1475]
       [DFX_INFO]Aicore kernel execute failed, device_id=1, stream_id=46, report_stream_id=46, task_id=0, flip_num=0, fault kernel_name=comm_p2p_binding_variants_kernel, fault kernel info ext=comm_p2p_binding_variants_kernel, program id=0, hash=16541545288638093324.[FUNC:GetError][FILE:stream.cc][LINE:1475]
       rtStreamSynchronize execution failed, reason=vector core exception[FUNC:FuncErrorReason][FILE:error_message_manage.cc][LINE:65]
       synchronize stream failed, runtime result = 507035[FUNC:ReportCallError][FILE:log_inner.cpp][LINE:148]
[2026-08-03 07:45:41] ERROR: testcase failed (exit 1): comm_p2p_binding_variants

comm_p2p

stage=run info=exit=1

[ERROR] aclrtSynchronizeStream(stream) failed: 507035 (/home/zhongxuan/ptoas-board-monitor/runtime/runs/20260803_071139_merged_pr1077/npu_validation/CommSync/comm_p2p/main.cpp:122)
[ERROR] RecentErrMsg: EZ9999: Inner Error!
EZ9999[PID: 3596433] 2026-08-03-07:45:59.301.908 (EZ9999):  The error from device(chipId:0, dieId:1), serial number is 2538, there is an exception of aivec error, core id is 16, error code = 0x10, dump info: pc start: 0x124200000000, current: 0x124200000168, vec error info: 0xdf00005f59, mte error info: 0xfd060000d3, ifu error info: 0x20000ffa63dc0, ccu error info: 0x40e008000000004f, cube error info: 0, biu error info: 0, aic error mask: 0x6500020bd00028c, para base: 0x12c100000000.[FUNC:PrintCoreInfo][FILE:device_error_core_proc.cc][LINE:645]
        TraceBack (most recent call last):
       The extend info: errcode:(0x10, 0, 0) errorStr: Illegal instruction, which is usually caused by unaligned UUB addresses. fixp_error0 info: 0x60000d3, fixp_error1 info: 0xfd, fsmId:1, tslot:6, thread:0, ctxid:0, blk:0, sublk:0, subErrType:4.[FUNC:PrintCoreInfo][FILE:device_error_core_proc.cc][LINE:658]
       Kernel task happen error, retCode=0x31, [vector core exception].[FUNC:PreCheckTaskErr][FILE:davinci_kernel_task.cc][LINE:1729]
       AIV Kernel happen error, retCode=0x31.[FUNC:GetError][FILE:stream.cc][LINE:1475]
       [AIC_INFO] after execute:args print end[FUNC:GetError][FILE:stream.cc][LINE:1475]
       [DFX_INFO]Aicore kernel execute failed, device_id=1, stream_id=46, report_stream_id=46, task_id=0, flip_num=0, fault kernel_name=comm_p2p_kernel, fault kernel info ext=comm_p2p_kernel, program id=0, hash=6260346515940177617.[FUNC:GetError][FILE:stream.cc][LINE:1475]
       rtStreamSynchronize execution failed, reason=vector core exception[FUNC:FuncErrorReason][FILE:error_message_manage.cc][LINE:65]
       synchronize stream failed, runtime result = 507035[FUNC:ReportCallError][FILE:log_inner.cpp][LINE:148]
[2026-08-03 07:46:00] ERROR: testcase failed (exit 1): comm_p2p