How to save and reuse outputs of different steps of synthesis in Design Compiler?
Yes, it is possible to save and/or load Design Compiler database at different stages of synthesis. Synopsys has DDC format to carry both design and constraint information. Files in this format are not human readable, but very useful.

The following example saves the database after elaboration.

analyze &lt;bla_bla&gt;
elaborate &lt;bla_bla&gt;
write_file -format ddc -output mydb_1.ddc


This example loads the saved database and saves again after compile.

read_ddc mydb_1.ddc
compile_ultra
write_file -format ddc -output mydb_2.ddc