This makes us also use max-iteration knowledge when considering costs
for prefetching and parallelization instead of only relying on
iteration estimates which are sometimes not available.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
Richard.
2012-04-11 Richard Guenther <rguent...@suse.de>
* tree-parloops.c (parallelize_loops): Also consult the upper
bound for the number of iterations.
* tree-ssa-loop-prefetch.c (determine_loop_nest_reuse): Likewise.
(loop_prefetch_arrays): Likewise.
Index: trunk/gcc/tree-parloops.c
===================================================================
*** trunk.orig/gcc/tree-parloops.c 2012-04-11 16:31:08.000000000 +0200
--- trunk/gcc/tree-parloops.c 2012-04-11 16:39:25.271205694 +0200
*************** parallelize_loops (void)
*** 2192,2203 ****
header-copied loops correctly - see PR46886. */
|| !do_while_loop_p (loop))
continue;
estimated = estimated_stmt_executions_int (loop);
/* FIXME: Bypass this check as graphite doesn't update the
! count and frequency correctly now. */
if (!flag_loop_parallelize_all
! && ((estimated !=-1
! && estimated <= (HOST_WIDE_INT) n_threads * MIN_PER_THREAD)
/* Do not bother with loops in cold areas. */
|| optimize_loop_nest_for_size_p (loop)))
continue;
--- 2192,2206 ----
header-copied loops correctly - see PR46886. */
|| !do_while_loop_p (loop))
continue;
+
estimated = estimated_stmt_executions_int (loop);
+ if (estimated == -1)
+ estimated = max_stmt_executions_int (loop);
/* FIXME: Bypass this check as graphite doesn't update the
! count and frequency correctly now. */
if (!flag_loop_parallelize_all
! && ((estimated != -1
! && estimated <= (HOST_WIDE_INT) n_threads * MIN_PER_THREAD)
/* Do not bother with loops in cold areas. */
|| optimize_loop_nest_for_size_p (loop)))
continue;
Index: trunk/gcc/tree-ssa-loop-prefetch.c
===================================================================
*** trunk.orig/gcc/tree-ssa-loop-prefetch.c 2012-04-11 16:31:08.000000000
+0200
--- trunk/gcc/tree-ssa-loop-prefetch.c 2012-04-11 16:42:45.864193724 +0200
*************** determine_loop_nest_reuse (struct loop *
*** 1549,1555 ****
aloop = VEC_index (loop_p, vloops, i);
vol = estimated_stmt_executions_int (aloop);
! if (vol < 0)
vol = expected_loop_iterations (aloop);
volume *= vol;
}
--- 1549,1555 ----
aloop = VEC_index (loop_p, vloops, i);
vol = estimated_stmt_executions_int (aloop);
! if (vol == -1)
vol = expected_loop_iterations (aloop);
volume *= vol;
}
*************** loop_prefetch_arrays (struct loop *loop)
*** 1801,1806 ****
--- 1801,1808 ----
ahead = (PREFETCH_LATENCY + time - 1) / time;
est_niter = estimated_stmt_executions_int (loop);
+ if (est_niter == -1)
+ est_niter = max_stmt_executions_int (loop);
/* Prefetching is not likely to be profitable if the trip count to ahead
ratio is too small. */
