On 3/10/2022 4:50 AM, Richard Biener via Gcc-patches wrote:
Currently back_propagate_equivalences tries to optimize dominance
queries in a smart way but it fails to notice that when fast indexes
are available the dominance query is fast (when called from DOM).
It also re-computes the dominance bitmap for each equivalence recorded
on an edge, which for FP are usually several. Finally it fails to
use the tree bitmap view for efficiency. Overall this cuts 7
seconds of compile-time from originally 77 in the slowest LTRANS
unit when building 521.wrf_r.
Bootstrap and regtest running on x86_64-unknown-linux-gnu.
Richard.
2022-03-10 Richard Biener <rguent...@suse.de>
PR tree-optimization/102943
* tree-ssa-dom.cc (back_propagate_equivalences): Only
populate the dominance bitmap if fast queries are not
available. Use a tree view bitmap.
(record_temporary_equivalences): Cache the dominance bitmap
across all equivalences on the edge.
Anything that helps WRF build times is a win in my book. IIRC the
worst module in there takes something like 27 minutes to cross compile
for our target. Annoying as hell when you have to do it multiple times
a day.
jeff
