On 10/20/2014 11:16 PM, Maxim Kuvyrkov wrote: > Hi, > > This patch cleans up (removes) cached_first_cycle_multipass_dfa_lookahead and > cached_issue_rate. > > These seem to be an artifact from the scheduler refactoring 10+ years ago. > They assume that dfa_lookahead and issue_rate can change mid-way through > scheduling, which is never the case. All backends currently treat > dfa_lookahead and issue_rate as constants for the duration of scheduling > passes. > > Bootstrapped on x86_64-linux-gnu. Regression testing is in progress. OK to > commit if no regressions? > Yes. the patch for issue rate itself is ok but you should have modified doc/tm.texi too for dfa lookahead hook saying that it should be a constant (issue rate already has such clause).
On the other hand I'd not assume that dfa look ahead is a constant. In future we could make it non-constant to differentiate non-hot and hot functions to speed up the scheduler as dfa look ahead scheduling is pretty expensive. So issue rate change is ok but I'd not rush to change dfa look ahead related code.
