https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118243
--- Comment #13 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Martin Jambor <jamb...@gcc.gnu.org>: https://gcc.gnu.org/g:0bffcd469e68d68ba9c724f515651deff8494b82 commit r15-7760-g0bffcd469e68d68ba9c724f515651deff8494b82 Author: Martin Jambor <mjam...@suse.cz> Date: Fri Feb 28 17:34:10 2025 +0100 ipa-sra: Avoid clashes with ipa-cp when pulling accesses across calls (PR 118243) Among other things, IPA-SRA checks whether splitting out a bit of an aggregate or something passed by reference would lead into a clash with an already known IPA-CP constant a way which would cause problems later on. Unfortunately the test is done only in adjust_parameter_descriptions and is missing when accesses are propagated from callees to callers, which leads to miscompilation reported as PR 118243 (where the callee is a function created by ipa-split). The matter is then further complicated by the fact that we consider complex numbers as scalars even though they can be modified piecemeal (IPA-CP can detect and propagate the pieces separately too) which then confuses the parameter manipulation machinery furter. This patch simply adds the missing check to avoid the IPA-SRA transform in these cases too, which should be suitable for backporting to all affected release branches. It is a bit of a shame as in the PR testcase we do propagate both components of the complex number in question and the transformation phase could recover. I have some prototype patches in this direction but that is something for (a) stage 1. gcc/ChangeLog: 2025-02-10 Martin Jambor <mjam...@suse.cz> PR ipa/118243 * ipa-sra.cc (pull_accesses_from_callee): New parameters caller_ipcp_ts and param_idx. Check that scalar pulled accesses would not clash with a known IPA-CP aggregate constant. (param_splitting_across_edge): Pass IPA-CP transformation summary and caller parameter index to pull_accesses_from_callee. gcc/testsuite/ChangeLog: 2025-02-10 Martin Jambor <mjam...@suse.cz> PR ipa/118243 * g++.dg/ipa/pr118243.C: New test.
