Finally. Boostrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard. 2012-04-18 Richard Guenther <rguent...@suse.de> PR tree-optimization/44688 * cfgloop.h (record_niter_bound): Declare. * tree-ssa-loop-niter.c (record_niter_bound): Export. Update the estimation with the upper bound here... (estimate_numbers_of_iterations_loop): ... instead of here. Do not forcefully reset a recorded upper bound. * tree-vect-loop-manip.c (vect_do_peeling_for_alignment): Record the maximum number of loop iterations of the prologue loop. Index: gcc/tree-ssa-loop-niter.c =================================================================== *** gcc/tree-ssa-loop-niter.c.orig 2012-04-18 10:55:55.000000000 +0200 --- gcc/tree-ssa-loop-niter.c 2012-04-18 11:39:25.368167852 +0200 *************** derive_constant_upper_bound_ops (tree ty *** 2494,2505 **** of iterations. UPPER is true if we are sure the loop iterates at most I_BOUND times. */ ! static void record_niter_bound (struct loop *loop, double_int i_bound, bool realistic, bool upper) { ! /* Update the bounds only when there is no previous estimation, or when the current ! estimation is smaller. */ if (upper && (!loop->any_upper_bound || double_int_ucmp (i_bound, loop->nb_iterations_upper_bound) < 0)) --- 2494,2505 ---- of iterations. UPPER is true if we are sure the loop iterates at most I_BOUND times. */ ! void record_niter_bound (struct loop *loop, double_int i_bound, bool realistic, bool upper) { ! /* Update the bounds only when there is no previous estimation, or when the ! current estimation is smaller. */ if (upper && (!loop->any_upper_bound || double_int_ucmp (i_bound, loop->nb_iterations_upper_bound) < 0)) *************** record_niter_bound (struct loop *loop, d *** 2514,2519 **** --- 2514,2527 ---- loop->any_estimate = true; loop->nb_iterations_estimate = i_bound; } + + /* If an upper bound is smaller than the realistic estimate of the + number of iterations, use the upper bound instead. */ + if (loop->any_upper_bound + && loop->any_estimate + && double_int_ucmp (loop->nb_iterations_upper_bound, + loop->nb_iterations_estimate) < 0) + loop->nb_iterations_estimate = loop->nb_iterations_upper_bound; } /* Records that AT_STMT is executed at most BOUND + 1 times in LOOP. IS_EXIT *************** estimate_numbers_of_iterations_loop (str *** 2962,2969 **** /* Give up if we already have tried to compute an estimation. */ if (loop->estimate_state != EST_NOT_COMPUTED) return; loop->estimate_state = EST_AVAILABLE; ! loop->any_upper_bound = false; loop->any_estimate = false; exits = get_loop_exit_edges (loop); --- 2970,2978 ---- /* Give up if we already have tried to compute an estimation. */ if (loop->estimate_state != EST_NOT_COMPUTED) return; + loop->estimate_state = EST_AVAILABLE; ! /* Force estimate compuation but leave any existing upper bound in place. */ loop->any_estimate = false; exits = get_loop_exit_edges (loop); *************** estimate_numbers_of_iterations_loop (str *** 2994,3007 **** bound = gcov_type_to_double_int (nit); record_niter_bound (loop, bound, true, false); } - - /* If an upper bound is smaller than the realistic estimate of the - number of iterations, use the upper bound instead. */ - if (loop->any_upper_bound - && loop->any_estimate - && double_int_ucmp (loop->nb_iterations_upper_bound, - loop->nb_iterations_estimate) < 0) - loop->nb_iterations_estimate = loop->nb_iterations_upper_bound; } /* Sets NIT to the estimated number of executions of the latch of the --- 3003,3008 ---- Index: gcc/tree-vect-loop-manip.c =================================================================== *** gcc/tree-vect-loop-manip.c.orig 2012-04-17 12:59:22.000000000 +0200 --- gcc/tree-vect-loop-manip.c 2012-04-18 11:39:25.368167852 +0200 *************** vect_do_peeling_for_alignment (loop_vec_ *** 2167,2172 **** --- 2167,2173 ---- struct loop *new_loop; unsigned int th = 0; int min_profitable_iters; + int max_iter; if (vect_print_dump_info (REPORT_DETAILS)) fprintf (vect_dump, "=== vect_do_peeling_for_alignment ==="); *************** vect_do_peeling_for_alignment (loop_vec_ *** 2192,2197 **** --- 2193,2203 ---- #ifdef ENABLE_CHECKING slpeel_verify_cfg_after_peeling (new_loop, loop); #endif + max_iter = MAX (LOOP_VINFO_VECT_FACTOR (loop_vinfo) - 1, (int) th); + record_niter_bound (new_loop, shwi_to_double_int (max_iter), false, true); + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Setting upper bound of nb iterations for prologue " + "loop to %d\n", max_iter); /* Update number of times loop executes. */ n_iters = LOOP_VINFO_NITERS (loop_vinfo); Index: gcc/cfgloop.h =================================================================== *** gcc/cfgloop.h.orig 2012-04-18 10:55:55.000000000 +0200 --- gcc/cfgloop.h 2012-04-18 11:39:49.936166250 +0200 *************** extern unsigned expected_loop_iterations *** 279,284 **** --- 279,285 ---- extern rtx doloop_condition_get (rtx); void estimate_numbers_of_iterations_loop (struct loop *); + void record_niter_bound (struct loop *, double_int, bool, bool); bool estimated_loop_iterations (struct loop *, double_int *); bool max_loop_iterations (struct loop *, double_int *); HOST_WIDE_INT estimated_loop_iterations_int (struct loop *);