[PATCH 1/4] df: Add -ftrack-subreg-liveness option

Add new flag -ftrack-subreg-liveness to enable track-subreg-liveness. This flag is enabled at -O3/fast. gcc/ChangeLog: * common.opt: add -ftrack-subreg-liveness option. * opts.cc: auto aneble -ftrack-subreg-liveness in -O3/fast --- gcc/common.opt | 4

[PATCH 1/4] df: Add -ftrack-subreg-liveness option

Add new flag -ftrack-subreg-liveness to enable track-subreg-liveness. This flag is enabled at -O3/fast. gcc/ChangeLog: * common.opt: add -ftrack-subreg-liveness option. * opts.cc: auto aneble -ftrack-subreg-liveness in -O3/fast --- gcc/common.opt | 4 gcc/opts.cc| 1 +