http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58862
--- Comment #4 from Teresa Johnson <tejohnson at google dot com> --- On Tue, Oct 29, 2013 at 8:05 AM, tejohnson at google dot com <gcc-bugzi...@gcc.gnu.org> wrote: > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58862 > > Teresa Johnson <tejohnson at google dot com> changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > CC| |tejohnson at gcc dot gnu.org, > | |tejohnson at google dot com > > --- Comment #3 from Teresa Johnson <tejohnson at google dot com> --- > I hit the "verify_flow_info: Wrong probability of edge" error in a > profiledbootstrap. I triaged this down to the following commit, made by me: > > ------------------------------------------------------------------------ > r203823 | tejohnson | 2013-10-18 07:36:53 -0700 (Fri, 18 Oct 2013) | 5 lines > Changed paths: > M /trunk/gcc/ChangeLog > M /trunk/gcc/tree-ssa-tail-merge.c > > 2013-10-18 Teresa Johnson <tejohn...@google.com> > > * tree-ssa-tail-merge.c (replace_block_by): Update edge > weights during merging. > > ------------------------------------------------------------------------ > > Investigating right now. Looks like there were profile weight insanities going > into this code, that were magnified by the fixes being performed by my change. > To avoid the error, I need to adjust the change I made to ensure that the > profile insanities don't get propagated into the edge probabilities. > > In the case I looked at, the edge weight insanities were originally introduced > during jump threading. I had previously made a fix to the profile updates > being > done by that optimization (r203041, committed by law), but there have been a > number of changes to that code since then so this needs to be revisited. > > I will get a fix for the failure though hopefully today. This patch fixes the profiledbootstrap errors I was looking at. Testing will a full profiledbootstrap and a regular bootstrap/regression test run. 2013-10-29 Teresa Johnson <tejohn...@google.com> * tree-ssa-tail-merge.c (replace_block_by): Tolerate profile insanities when updating probabilities. Index: tree-ssa-tail-merge.c =================================================================== --- tree-ssa-tail-merge.c (revision 204166) +++ tree-ssa-tail-merge.c (working copy) @@ -1467,7 +1467,7 @@ static void replace_block_by (basic_block bb1, basic_block bb2) { edge pred_edge; - edge e1; + edge e1, e2; edge_iterator ei; unsigned int i; gimple bb2_phi; @@ -1502,16 +1502,22 @@ replace_block_by (basic_block bb1, basic_block bb2 bb2->count += bb1->count; /* Merge the outgoing edge counts from bb1 onto bb2. */ + gcov_type out_sum = 0; FOR_EACH_EDGE (e1, ei, bb1->succs) { - edge e2; e2 = find_edge (bb2, e1->dest); gcc_assert (e2); e2->count += e1->count; - /* Recompute the probability from the new merged edge count (bb2->count - was updated above). */ - e2->probability = GCOV_COMPUTE_SCALE (e2->count, bb2->count); + out_sum += e2->count; } + /* Recompute the edge probabilities from the new merged edge count. + Use the sum of the new merged edge counts computed above instead + of bb2's merged count, in case there are profile count insanities + making the bb count inconsistent with the edge weights. */ + FOR_EACH_EDGE (e2, ei, bb2->succs) + { + e2->probability = GCOV_COMPUTE_SCALE (e2->count, out_sum); + } /* Do updates that use bb1, before deleting bb1. */ release_last_vdef (bb1); > > Thanks, > Teresa > > -- > You are receiving this mail because: > You are on the CC list for the bug.
