On 10/14/2021 8:25 AM, Aldy Hernandez wrote:
The new backward threader makes some of the --param knobs used to
control it questionable at best or no longer applicable at worst.
The fsm-maximum-phi-arguments param is unused and can be removed.
The max-fsm-thread-length param is block based which is a bit redundant,
since we already restrict paths based on instruction estimates.
The max-fsm-thread-paths restricts the total number of threadable paths
in a function. We probably don't need this. Besides, the forward
threader has no such restriction.
OK pending tests?
gcc/ChangeLog:
* doc/invoke.texi: Remove max-fsm-thread-length,
max-fsm-thread-paths, and fsm-maximum-phi-arguments.
* params.opt: Same.
* tree-ssa-threadbackward.c (back_threader::back_threader): Remove
argument.
(back_threader_registry::back_threader_registry): Same.
(back_threader_profitability::profitable_path_p): Remove
param_max_fsm_thread-length.
(back_threader_registry::register_path): Remove
m_max_allowable_paths.
OK. I don't think any of those params were addressing pathological
cases and thread-length is really handled better by costing based on the
# statements.
jeff
