http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57482
Bug ID: 57482 Summary: --help=optimizers reports a wrong list Product: gcc Version: 4.7.3 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: christophe.beausoleil at sogeti dot com Hello, I am using GCC 4.7.3 built for AVR targets on a Linux machine. The command : avr-gcc -mmcu=atmega128 -O1 -Q --help=optimizers returns a list of enabled options for the -O1 optimization level. Among these enabled options is : -fshort-enums [enabled] However, I can see that this option is not enabled by -O1. I simply did : typedef enum {val1, val2} Tenum; Tenum Venum; I compile with : avr-gcc -mmcu=atmega128 -O1 test.c -o test.elf and check Venum size with : avr-nm -S test.elf | grep Venum which gives : 00800109 00000002 B Venum I have to explicitly use -fshort-enums in my command line in order that GCC takes it into account : 00800109 00000001 B Venum I must also add that the problem is the same for -00 and -02. The question is : how can I know which options are effectively enabled or not ? Can I easily find the answer in source code ? Thanks a lot for reading till here and for any support ! Best regards Christophe