https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58195
--- Comment #13 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Andrew Pinski <pins...@gcc.gnu.org>: https://gcc.gnu.org/g:35bf490452e06b3e3567933342fb15ef5d11f503 commit r15-4689-g35bf490452e06b3e3567933342fb15ef5d11f503 Author: Andrew Pinski <quic_apin...@quicinc.com> Date: Sun Oct 20 10:44:14 2024 -0700 simplify-rtx: Handle `a != 0 ? -a : 0` [PR58195] The gimple (and generic) levels have this optmization since r12-2041-g7d6979197274a662da7bdc5. It seems like a good idea to add a similar one to rtl just in case it is not caught at the gimple level. Note the loop case in csel-neg-1.c is not handled at the gimple level (even with phiopt turned back on), this is because of casts to avoid signed integer overflow; a patch to fix this at the gimple level will be submitted seperately. Changes since v1: * v2: Use `CONST0_RTX (mode)` instead of const0_rtx. Add csel-neg-2.c for float testcase which now passes. Build and tested for aarch64-linux-gnu. PR rtl-optimization/58195 gcc/ChangeLog: * simplify-rtx.cc (simplify_context::simplify_ternary_operation): Handle `a != 0 ? -a : 0` and `a == 0 ? 0 : -a`. gcc/testsuite/ChangeLog: * gcc.target/aarch64/csel-neg-1.c: New test. * gcc.target/aarch64/csel-neg-2.c: New test. Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
