https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123308
--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Andrew Pinski <[email protected]>: https://gcc.gnu.org/g:92f2a86794ad88d773b102c753e13be1b6f05ff9 commit r16-6436-g92f2a86794ad88d773b102c753e13be1b6f05ff9 Author: Andrew Pinski <[email protected]> Date: Fri Dec 26 12:07:26 2025 -0800 ifcvt: Handle lowpart subregs if noce_emit_cmove fails in noce_try_cond_zero_arith [PR123308] This fixes up a missed optimization regression for riscv in ifcvt after r16-6350-g9e61a171244110. The problem is noce_emit_cmove will fail for QImode. This can show up when dealing with shifts and the right hand side is `(subreg:QI (reg:DI) lowpart)`. Trying first for the subreg mode fails so the need to try to unwrap the subreg and try for the full mode. This fixes test_ShiftLeft_eqz in gcc.target/riscv/zicond_ifcvt_opt.c. Bootstrapped and tested on x86_64-linux-gnu. PR rtl-optimization/123308 gcc/ChangeLog: * ifcvt.cc (noce_try_cond_zero_arith): If noce_emit_cmove fails for a lowpart subreg case, then try the full reg cmove and take the lowpart subreg afterwards. Signed-off-by: Andrew Pinski <[email protected]>
