请教conformal中unreachable point的排除问题
时间：10-02
整理：3721RD
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我在使用conformal LEC做rtl与netlist做验证的时候，工具报告出很多unreachable point，其中相当一部分并不是没有fanout的点，请问要如何分析tool给出的这段报告来判断是否这个unreachable point是否可以忽略?我从fanin/fanout的信息中没法判断出为什么tool说这是个unreachable point.
请大家给些建议~谢谢！
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/ Command: report gate uvc/rdc8051/rst_osc_ctl/pHFWake_reg -golden -unreach ================================================================================ Pin-name ID (Golden) Type Tie Gate-name ================================================================================ 1765 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg ------ Fanins ------------------------------------------------------------------ 1: 'S' 6792 ZERO /uvc/rdc8051/rst_osc_ctl/N$4 2: 'R' 6792 ZERO /uvc/rdc8051/rst_osc_ctl/N$4 3: 'CK' 19219 AND /uvc/clk_gen/DNT_ANDCPUCLK/U$1 4: 'D' 34584 AND /uvc/rdc8051/rst_osc_ctl/U$27 ------ Fanouts ----------------------------------------------------------------- 1: 34575 INV /uvc/rdc8051/rst_osc_ctl/U$57 2: 34573 AND /uvc/rdc8051/rst_osc_ctl/U$53 3: 34579 AND /uvc/rdc8051/rst_osc_ctl/U$30 ================================================================================ // Report unreachable information for '1765 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg' // 1: Reached '1788 DFF /uvc/rdc8051/rst_osc_ctl/pFWake_reg' // 2: Reached '1765 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg' // 3: Stopped at '1765 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg' due to visited // This gate is unreachable from any primary output // Command: report gate uvc/rdc8051/rst_osc_ctl/pHFWake_reg/_i0/U$1 -revised -unreach ================================================================================ Pin-name ID (Revised) Type Tie Gate-name (Library: FFDHD1X) ================================================================================ 1760 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/_i0/U$1 ------ Fanins ------------------------------------------------------------------ 1: 'S' 11570 INV (L0) /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/U$0 2: 'R' 11571 AND (L0) /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/U$3 3: 'CK' 34194 AND /uvc/clk_gen/DNT_ANDCPUCLK/U$1 4: 'D' 57327 OR /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/U$4 ------ Fanouts ----------------------------------------------------------------- 1: 62962 AND /uvc/rdc8051/rst_osc_ctl/pFWake_reg/U$6 2: 57317 INV /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/_i1 ================================================================================ // Report unreachable information for '1760 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/_i0/U$1' // 1: Reached '1785 DFF /uvc/rdc8051/rst_osc_ctl/pFWake_reg/_i0/U$1' // 2: Reached '1760 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/_i0/U$1' // 3: Stopped at '1760 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/_i0/U$1' due to visited // This gate is unreachable from any primary output 我從報告出的fanin/fanout，以及report的信息，判斷不出爲什麽tool會認為這個FF是unreachable的。想請教您該如何去分析tool給出的這組信息?
请大家给些建议~谢谢！
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/ Command: report gate uvc/rdc8051/rst_osc_ctl/pHFWake_reg -golden -unreach ================================================================================ Pin-name ID (Golden) Type Tie Gate-name ================================================================================ 1765 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg ------ Fanins ------------------------------------------------------------------ 1: 'S' 6792 ZERO /uvc/rdc8051/rst_osc_ctl/N$4 2: 'R' 6792 ZERO /uvc/rdc8051/rst_osc_ctl/N$4 3: 'CK' 19219 AND /uvc/clk_gen/DNT_ANDCPUCLK/U$1 4: 'D' 34584 AND /uvc/rdc8051/rst_osc_ctl/U$27 ------ Fanouts ----------------------------------------------------------------- 1: 34575 INV /uvc/rdc8051/rst_osc_ctl/U$57 2: 34573 AND /uvc/rdc8051/rst_osc_ctl/U$53 3: 34579 AND /uvc/rdc8051/rst_osc_ctl/U$30 ================================================================================ // Report unreachable information for '1765 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg' // 1: Reached '1788 DFF /uvc/rdc8051/rst_osc_ctl/pFWake_reg' // 2: Reached '1765 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg' // 3: Stopped at '1765 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg' due to visited // This gate is unreachable from any primary output // Command: report gate uvc/rdc8051/rst_osc_ctl/pHFWake_reg/_i0/U$1 -revised -unreach ================================================================================ Pin-name ID (Revised) Type Tie Gate-name (Library: FFDHD1X) ================================================================================ 1760 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/_i0/U$1 ------ Fanins ------------------------------------------------------------------ 1: 'S' 11570 INV (L0) /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/U$0 2: 'R' 11571 AND (L0) /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/U$3 3: 'CK' 34194 AND /uvc/clk_gen/DNT_ANDCPUCLK/U$1 4: 'D' 57327 OR /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/U$4 ------ Fanouts ----------------------------------------------------------------- 1: 62962 AND /uvc/rdc8051/rst_osc_ctl/pFWake_reg/U$6 2: 57317 INV /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/_i1 ================================================================================ // Report unreachable information for '1760 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/_i0/U$1' // 1: Reached '1785 DFF /uvc/rdc8051/rst_osc_ctl/pFWake_reg/_i0/U$1' // 2: Reached '1760 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/_i0/U$1' // 3: Stopped at '1760 DFF /uvc/rdc8051/rst_osc_ctl/pHFWake_reg/_i0/U$1' due to visited // This gate is unreachable from any primary output 我從報告出的fanin/fanout，以及report的信息，判斷不出爲什麽tool會認為這個FF是unreachable的。想請教您該如何去分析tool給出的這組信息?
我的report里也有很多个unreachable points，仔细查看了一下
是很多定义的reg没用到的bits，感觉没关系
别人设计的东西多出来的没用到的bits
太复杂的东东
咱也不懂
unreachable表示对output没有贡献，也就是这些points与output port没有数据路径。
如果一个DFF为unreachable ，可能导致其fanin相关的DFF也为unreachable。
coformal
thanks
thanks！
目前，许多感谢。
需要debug
一般来说unreachable的都是对输出没有贡献的，可以不管的。
学到了，谢谢
please check your pin constraint first.
very good data
同问，LEC太复杂，有没有快速上手的资料或者实验啊?
unreachable和EXTRA类型的unmap点，不会对Key point造成影响，对逻辑锥比对没有贡献。not mapped类型，则需要确认。否则通常会导致FAIL。
以前用formality时，有很多其他报告可以帮忙发现设计缺陷。比如not compareunmap，等等。刚开始用CONFORMAL有些不习惯，mapping report, nonequal,abort, 没了?