Grigori,
Many of the costs now are handled by GCC parameters. See
gcc/params.def accessed in the source code using PARAM_VALUE.
Many other cost models use macros with COST in their name, such as
TARGET_RTX_COSTS / rtx_cost
BRANCH_COST (and LOGICAL_OP_NON_SHORT_CIRCUIT)
Thanks, David!
That's a good start. I will need to find places in GCC where these
parameters are used to monitor the behavior of transformations
based on these parameters and be able to change the compiler decisions
through ICI to learn how to tune those costs based on program execution