https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115478
--- Comment #11 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jeff Law <l...@gcc.gnu.org>: https://gcc.gnu.org/g:71f6540fc54036cc8f71db497cc22816f794549a commit r15-7483-g71f6540fc54036cc8f71db497cc22816f794549a Author: Jeff Law <j...@ventanamicro.com> Date: Tue Feb 11 16:55:03 2025 -0700 [PR target/115478] Accept ADD, IOR or XOR when combining objects with no bits in common So the change to prefer ADD over IOR for combining two objects with no bits in common is (IMHO) generally good. It has some minor fallout. In particular the aarch64 port (and I suspect others) have patterns that recognize IOR, but not PLUS or XOR for these cases and thus tests which expected to optimize with IOR are no longer optimizing. Roger suggested using a code iterator for this purpose. Richard S. suggested a new match operator to cover those cases. I really like the match operator idea, but as Richard S. notes in the PR it would require either not validating the "no bits in common", which dramatically reduces the utility IMHO or we'd need some work to allow consistent results without polluting the nonzero bits cache. So this patch goes back to Roger's idea of just using a match iterator in the aarch64 backend (and presumably anywhere else we see this popping up). Bootstrapped and regression tested on aarch64-linux-gnu where it fixes bitint-args.c (as expected). PR target/115478 gcc/ * config/aarch64/iterators.md (any_or_plus): New code iterator. * config/aarch64/aarch64.md (extr<mode>5_insn): Use any_or_plus. (extr<mode>5_insn_alt, extrsi5_insn_uxtw): Likewise. (extrsi5_insn_uxtw_alt, extrsi5_insn_di): Likewise. gcc/testsuite/ * gcc.target/aarch64/bitint-args.c: Update expected output.
