how to get the timing report register to register and input to output in STA?
The all_registers command can be used to get a collection of sequential cells. The basic use of it is not different from all_inputs and all_outputs commands.

The 4 timing reports may be generated as follows.


report_timing -from [all_inputs]               -to [all_registers -data_pins]
report_timing -from [all_registers -data_pins] -to [all_registers -data_pins]
report_timing -from [all_registers -data_pins] -to [all_outputs]
report_timing -from [all_inputs]               -to [all_outputs]


Note: PrimeTime supports that command as well as Design Compiler, but -data_pins (or -clock_pins) switch is mandatory for Design Compiler only.