https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114557
--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Richard Biener <rgue...@gcc.gnu.org>: https://gcc.gnu.org/g:e7b7188b1cf8c174f0e890d4ac279ff480b51043 commit r14-9767-ge7b7188b1cf8c174f0e890d4ac279ff480b51043 Author: Richard Biener <rguent...@suse.de> Date: Tue Apr 2 12:31:04 2024 +0200 tree-optimization/114557 - reduce ehcleanup peak memory use The following reduces peak memory use for the PR114480 testcase at -O1 which is almost exclusively spent by the ehcleanup pass in allocating PHI nodes. The free_phinodes cache we maintain isn't very effective since it has effectively two slots, one for 4 and one for 9 argument PHIs and it is only ever used for allocations up to 9 arguments but we put all larger PHIs in the 9 argument bucket. This proves uneffective resulting in much garbage to be kept when incrementally growing PHI nodes by edge redirection. The mitigation is to rely on the GC freelist for larger sizes and thus immediately return all larger bucket sized PHIs to it via ggc_free. This reduces the peak memory use from 19.8GB to 11.3GB and compile-time from 359s to 168s. PR tree-optimization/114557 PR tree-optimization/114480 * tree-phinodes.cc (release_phi_node): Return PHIs from allocation buckets not covered by free_phinodes to GC. (remove_phi_node): Release the PHI LHS before freeing the PHI node. * tree-vect-loop.cc (vectorizable_live_operation): Get PHI lhs before releasing it.
