Starting with the IBM Automatic Binary Optimizer for z/OS (ABO) V1.3 continuous delivery PTF,  released Jan 27, 2019, you can now use ABO to optimize modules built with the CMPR2 compiler option. 

The CMPR2 compiler option was available in COBOL compilers VS COBOL II V3 up to COBOL for OS/390®  V2 and allowed COBOL code conforming to the 74 COBOL standard to be successfully compiled.  Enterprise COBOL does not support this option and requires that code is migrated to the 85 COBOL standard.  Clients with programs compiled with the CMPR2 option will now be able to optimize them using ABO to take advantage of the latest Z hardware facilities and optimization technology to improve application performance without the need to migrate their COBOL code. 

For more information, please see page 264 of the COBOL compiler Programming Guide.