https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93491
--- Comment #7 from CVS 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:13a43a90aea368a25da50762eba4873bafb4e448 commit r12-3284-g13a43a90aea368a25da50762eba4873bafb4e448 Author: Richard Biener <rguent...@suse.de> Date: Wed Sep 1 11:49:39 2021 +0200 tree-optimization/93491 - avoid PRE of trapping calls across exits This makes us avoid PREing calls that could trap across other calls that might not return. The PR88087 testcase has exactly such case so I've refactored the testcase to contain a valid PRE. I've also adjusted PRE to not consider pure calls possibly not returning in line with what we do elsewhere. Note we don't have a good idea whether a function always returns normally or whether its body is known to never trap. That's something IPA could compute. 2021-09-01 Richard Biener <rguent...@suse.de> PR tree-optimization/93491 * tree-ssa-pre.c (compute_avail): Set BB_MAY_NOTRETURN after processing the stmt itself. Do not consider pure functions possibly not returning. Properly avoid adding possibly trapping calls to EXP_GEN when there's a preceeding possibly not returning call. * tree-ssa-sccvn.c (vn_reference_may_trap): Conservatively not handle calls. * gcc.dg/torture/pr93491.c: New testcase. * gcc.dg/tree-ssa/pr88087.c: Change to valid PRE opportunity.
