Jiufu Guo via Gcc-patches <gcc-patches@gcc.gnu.org> writes: Hi,
I would like to reping this, hope to get approval for this patch. https://gcc.gnu.org/legacy-ml/gcc-patches/2020-02/msg00927.html BR, Jiufu Guo > Jiufu Guo <guoji...@linux.ibm.com> writes: > > Hi, > > I'd like to ping this patch for trunk on stage 1. > > This patch could fix the issue on incorrect COUNT/FREQUENCES of loop > unrolled blocks, and also could help the improve the cold/hot issue of > the unrolled loops. > > patch is also at > https://gcc.gnu.org/legacy-ml/gcc-patches/2020-02/msg00927.html > > Thanks, > Jiufu > >> Jiufu Guo <guoji...@linux.ibm.com> writes: >> >> Hi! >> >> I'd like to ping following patch. As near end of gcc10 stage 4, it seems >> I would ask approval for GCC11 trunk. >> >> Thanks, >> Jiufu Guo >> >>> Hi Honza and all, >>> >>> I updated the patch a little as below. Bootstrap and regtest are ok >>> on powerpc64le. >>> >>> Is OK for trunk? >>> >>> Thanks for comments. >>> Jiufu >>> >>> diff --git a/gcc/cfgloopmanip.c b/gcc/cfgloopmanip.c >>> index 727e951..ded0046 100644 >>> --- a/gcc/cfgloopmanip.c >>> +++ b/gcc/cfgloopmanip.c >>> @@ -31,6 +31,7 @@ along with GCC; see the file COPYING3. If not see >>> #include "gimplify-me.h" >>> #include "tree-ssa-loop-manip.h" >>> #include "dumpfile.h" >>> +#include "cfgrtl.h" >>> >>> static void copy_loops_to (class loop **, int, >>> class loop *); >>> @@ -1258,14 +1259,30 @@ duplicate_loop_to_header_edge (class loop *loop, >>> edge e, >>> /* If original loop is executed COUNT_IN times, the unrolled >>> loop will account SCALE_MAIN_DEN times. */ >>> scale_main = count_in.probability_in (scale_main_den); >>> + >>> + /* If we are guessing at the number of iterations and count_in >>> + becomes unrealistically small, reset probability. */ >>> + if (!(count_in.reliable_p () || loop->any_estimate)) >>> + { >>> + profile_count new_count_in = count_in.apply_probability >>> (scale_main); >>> + profile_count preheader_count = loop_preheader_edge (loop)->count >>> (); >>> + if (new_count_in.apply_scale (1, 10) < preheader_count) >>> + scale_main = profile_probability::likely (); >>> + } >>> + >>> scale_act = scale_main * prob_pass_main; >>> } >>> else >>> { >>> + profile_count new_loop_count; >>> profile_count preheader_count = e->count (); >>> - for (i = 0; i < ndupl; i++) >>> - scale_main = scale_main * scale_step[i]; >>> scale_act = preheader_count.probability_in (count_in); >>> + /* Compute final preheader count after peeling NDUPL copies. */ >>> + for (i = 0; i < ndupl; i++) >>> + preheader_count = preheader_count.apply_probability (scale_step[i]); >>> + /* Subtract out exit(s) from peeled copies. */ >>> + new_loop_count = count_in - (e->count () - preheader_count); >>> + scale_main = new_loop_count.probability_in (count_in); >>> } >>> } >>> >>> @@ -1381,6 +1398,38 @@ duplicate_loop_to_header_edge (class loop *loop, >>> edge e, >>> scale_bbs_frequencies (new_bbs, n, scale_act); >>> scale_act = scale_act * scale_step[j]; >>> } >>> + >>> + /* Need to update PROB of exit edge and corresponding COUNT. */ >>> + if (orig && is_latch && (!bitmap_bit_p (wont_exit, j + 1)) >>> + && bbs_to_scale) >>> + { >>> + edge new_exit = new_spec_edges[SE_ORIG]; >>> + profile_count new_count_in = new_exit->src->count; >>> + profile_count preheader_count = loop_preheader_edge (loop)->count (); >>> + edge e; >>> + edge_iterator ei; >>> + >>> + FOR_EACH_EDGE (e, ei, new_exit->src->succs) >>> + if (e != new_exit) >>> + break; >>> + >>> + gcc_assert (e && e != new_exit); >>> + >>> + new_exit->probability = preheader_count.probability_in (new_count_in); >>> + e->probability = new_exit->probability.invert (); >>> + >>> + profile_count new_latch_count >>> + = new_exit->src->count.apply_probability (e->probability); >>> + profile_count old_latch_count = e->dest->count; >>> + >>> + EXECUTE_IF_SET_IN_BITMAP (bbs_to_scale, 0, i, bi) >>> + scale_bbs_frequencies_profile_count (new_bbs + i, 1, >>> + new_latch_count, >>> + old_latch_count); >>> + >>> + if (current_ir_type () != IR_GIMPLE) >>> + update_br_prob_note (e->src); >>> + } >>> } >>> free (new_bbs); >>> free (orig_loops); >>> diff --git a/gcc/testsuite/gcc.dg/pr68212.c b/gcc/testsuite/gcc.dg/pr68212.c >>> new file mode 100644 >>> index 0000000..f3b7c22 >>> --- /dev/null >>> +++ b/gcc/testsuite/gcc.dg/pr68212.c >>> @@ -0,0 +1,13 @@ >>> +/* { dg-do compile } */ >>> +/* { dg-options "-O2 -fno-tree-vectorize -funroll-loops --param >>> max-unroll-times=4 -fdump-rtl-alignments" } */ >>> + >>> +void foo(long int *a, long int *b, long int n) >>> +{ >>> + long int i; >>> + >>> + for (i = 0; i < n; i++) >>> + a[i] = *b; >>> +} >>> + >>> +/* { dg-final { scan-rtl-dump-times "internal loop alignment added" 1 >>> "alignments"} } */ >>> +
