From: Matt Turner Date: Wed, 16 Apr 2014 05:46:55 +0000 (-0700) Subject: i965/fs: Reduce restrictions on interference in register coalescing. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=f770123f58b46459e8dbd27525162ee8ba89f30b;p=mesa.git i965/fs: Reduce restrictions on interference in register coalescing. We previously only allowed coalescing registers that interfere (i.e., whose live ranges overlap) if the destination register's live range was entirely inside the source's live range. This is unnecessary -- we only need to check for interfering writes in the intersection of their live ranges. total instructions in shared programs: 1639470 -> 1638453 (-0.06%) instructions in affected programs: 84751 -> 83734 (-1.20%) Reviewed-by: Kenneth Graunke --- diff --git a/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp b/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp index b2ab386ab66..13b678afdc4 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_register_coalesce.cpp @@ -83,19 +83,6 @@ can_coalesce_vars(brw::fs_live_variables *live_intervals, if (!live_intervals->vars_interfere(var_from, var_to)) return true; - /* We know that the live ranges of A (var_from) and B (var_to) - * interfere because of the ->vars_interfere() call above. If the end - * of B's live range is after the end of A's range, then we know two - * things: - * - the start of B's live range must be in A's live range (since we - * already know the two ranges interfere, this is the only remaining - * possibility) - * - the interference isn't of the form we're looking for (where B is - * entirely inside A) - */ - if (live_intervals->end[var_to] > live_intervals->end[var_from]) - return false; - assert(ip >= live_intervals->start[var_to]); fs_inst *scan_inst;