man compile_ultra 中的 -spg解释到:
Physical [size=14.3999996185303px]guidance enables Design Compiler Graphical to save coarse place[size=14.3999996185303px]ment information and pass this coarse placement [size=14.3999996185303px]information to
[size=14.3999996185303px]IC Compiler. With this coarse placement, IC Compiler can begin [size=14.3999996185303px]the implementation flow with the [size=14.3999996185303px]place_opt
[size=14.3999996185303px]command.