https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103743
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jiu Fu Guo <guoji...@gcc.gnu.org>: https://gcc.gnu.org/g:1060cd2ad00b5174f4f8ef8ca3d8c283e321ffca commit r13-4803-g1060cd2ad00b5174f4f8ef8ca3d8c283e321ffca Author: Jiufu Guo <guoji...@linux.ibm.com> Date: Tue Dec 20 11:43:57 2022 +0800 rs6000: Optimize cmp on rotated 16bits constant Hi, When checking eq/ne with a constant which has only 16bits, it can be optimized to check the rotated data. By this, the constant building is optimized. As the example in PR103743: For "in == 0x8000000000000000LL", this patch generates: rotldi 3,3,1 ; cmpldi 0,3,1 instead of: li 9,-1 ; rldicr 9,9,0,0 ; cmpd 0,3,9 Compare with previous version: https://gcc.gnu.org/pipermail/gcc-patches/2022-August/600475.html. This patch refactor the code according to review comments. e.g. updating function names/comments/code. This patch pass bootstrap and regtest on ppc64 and ppc64le. Is it ok for trunk? Thanks for comments! BR, Jeff(Jiufu) PR target/103743 gcc/ChangeLog: * config/rs6000/rs6000-protos.h (can_be_rotated_to_lowbits): New. (can_be_rotated_to_positive_16bits): New. (can_be_rotated_to_negative_15bits): New. * config/rs6000/rs6000.cc (can_be_rotated_to_lowbits): New definition. (can_be_rotated_to_positive_16bits): New definition. (can_be_rotated_to_negative_15bits): New definition. * config/rs6000/rs6000.md (*rotate_on_cmpdi): New define_insn_and_split. (eqne): Move earlier. gcc/testsuite/ChangeLog: * gcc.target/powerpc/pr103743.c: New test. * gcc.target/powerpc/pr103743_1.c: New test.
