https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111820
--- Comment #11 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by hongtao Liu <liuho...@gcc.gnu.org>: https://gcc.gnu.org/g:dbde384bd56f07bfbcae86f81fc74aa92e3786ad commit r14-4834-gdbde384bd56f07bfbcae86f81fc74aa92e3786ad Author: liuhongt <hongtao....@intel.com> Date: Wed Oct 18 10:08:24 2023 +0800 Avoid compile time hog on vect_peel_nonlinear_iv_init for nonlinear induction vec_step_op_mul when iteration count is too big. There's loop in vect_peel_nonlinear_iv_init to get init_expr * pow (step_expr, skip_niters). When skipn_iters is too big, compile time hogs. To avoid that, optimize init_expr * pow (step_expr, skip_niters) to init_expr << (exact_log2 (step_expr) * skip_niters) when step_expr is pow of 2, otherwise give up vectorization when skip_niters >= TYPE_PRECISION (TREE_TYPE (init_expr)). Also give up vectorization when niters_skip is negative which will be used for fully masked loop. gcc/ChangeLog: PR tree-optimization/111820 PR tree-optimization/111833 * tree-vect-loop-manip.cc (vect_can_peel_nonlinear_iv_p): Give up vectorization for nonlinear iv vect_step_op_mul when step_expr is not exact_log2 and niters is greater than TYPE_PRECISION (TREE_TYPE (step_expr)). Also don't vectorize for nagative niters_skip which will be used by fully masked loop. (vect_can_advance_ivs_p): Pass whole phi_info to vect_can_peel_nonlinear_iv_p. * tree-vect-loop.cc (vect_peel_nonlinear_iv_init): Optimize init_expr * pow (step_expr, skipn) to init_expr << (log2 (step_expr) * skipn) when step_expr is exact_log2. gcc/testsuite/ChangeLog: * gcc.target/i386/pr111820-1.c: New test. * gcc.target/i386/pr111820-2.c: New test. * gcc.target/i386/pr111820-3.c: New test. * gcc.target/i386/pr103144-mul-1.c: Adjust testcase. * gcc.target/i386/pr103144-mul-2.c: Adjust testcase.
