https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79958
--- Comment #6 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:1e0ae1f52741f7e0133661659ed2d210f939a398 commit r15-571-g1e0ae1f52741f7e0133661659ed2d210f939a398 Author: Richard Biener <rguent...@suse.de> Date: Wed May 15 18:32:37 2024 +0200 tree-optimization/79958 - make DSE track multiple paths DSE currently gives up when the path we analyze forks. This leads to multiple missed dead store elimination PRs. The following fixes this by recursing for each path and maintaining the visited bitmap to avoid visiting CFG re-merges multiple times. The overall cost is still limited by the same bound, it's just more likely we'll hit the limit now. The patch doesn't try to deal with byte tracking once a path forks but drops info on the floor and only handling fully dead stores in that case. PR tree-optimization/79958 PR tree-optimization/109087 PR tree-optimization/100314 PR tree-optimization/114774 * tree-ssa-dse.cc (dse_classify_store): New forwarder. (dse_classify_store): Add arguments cnt and visited, recurse to track multiple paths when we end up with multiple defs. * gcc.dg/tree-ssa/ssa-dse-48.c: New testcase. * gcc.dg/tree-ssa/ssa-dse-49.c: Likewise. * gcc.dg/tree-ssa/ssa-dse-50.c: Likewise. * gcc.dg/tree-ssa/ssa-dse-51.c: Likewise. * gcc.dg/graphite/pr80906.c: Avoid DSE of last data reference in loop. * g++.dg/ipa/devirt-24.C: Adjust for extra DSE. * g++.dg/warn/Wuninitialized-pr107919-1.C: Use more important -O2 optimization level, -O1 regresses.
