On Thu, May 12, 2011 at 4:42 PM, Jakub Jelinek <ja...@redhat.com> wrote: > Hi! > > combine_blocks at the end removes most of the bbs, keeps around just > loop header, maybe latch and maybe exit_bb. We need to free bb->aux > through free_bb_predicate, but that is done in the caller, using array of > (former) loop bbs, with the new loop->num_nodes count (at most 3). > While that properly frees bb->aux for loop->header, it might very well > access bb->aux of deleted bbs and free that, for most of the deleted > bbs will leak memory and might keep around bb->aux for latch and/or exit_bb > (which is incorrect as following passes expect that bb->aux is NULL upon > entry - shouldn't we with ENABLE_CHECKING verify bb->aux is NULL after > every pass instead of just testing it at the beginning of a couple of > passes?).
I think verify_flow might be a good place to check this. > Fixed by calling free_bb_predicate already before deleting > any bbs, for all bbs in the loop, and making sure the caller doesn't do it > again. > > Bootstrapped/regtested on x86_64linux and i686-linux, ok for trunk? Ok. Thanks, Richard. > 2011-05-12 Jakub Jelinek <ja...@redhat.com> > > PR tree-optimization/48975 > * tree-if-conv.c (combine_blocks): Call free_bb_predicate > on all bbs here and free and clear ifc_bbs at the end. > > * gcc.dg/pr48975.c: New test. > > --- gcc/tree-if-conv.c.jj 2011-05-02 18:39:28.000000000 +0200 > +++ gcc/tree-if-conv.c 2011-05-12 12:20:33.000000000 +0200 > @@ -1637,6 +1637,7 @@ combine_blocks (struct loop *loop) > for (i = 0; i < orig_loop_num_nodes; i++) > { > bb = ifc_bbs[i]; > + free_bb_predicate (bb); > if (bb_with_exit_edge_p (loop, bb)) > { > exit_bb = bb; > @@ -1712,6 +1713,9 @@ combine_blocks (struct loop *loop) > && exit_bb != loop->header > && can_merge_blocks_p (loop->header, exit_bb)) > merge_blocks (loop->header, exit_bb); > + > + free (ifc_bbs); > + ifc_bbs = NULL; > } > > /* If-convert LOOP when it is legal. For the moment this pass has no > --- gcc/testsuite/gcc.dg/pr48975.c.jj 2011-05-12 12:23:59.000000000 +0200 > +++ gcc/testsuite/gcc.dg/pr48975.c 2011-05-12 12:23:51.000000000 +0200 > @@ -0,0 +1,18 @@ > +/* PR tree-optimization/48975 */ > +/* { dg-do compile } */ > +/* { dg-options "-O3 -ffast-math -fno-tree-slp-vectorize" } */ > + > +static int > +foo (int x) > +{ > + return (x > 0) ? 0 : x + 1; > +} > + > +void > +bar (unsigned int x) > +{ > + int l = 1; > +lab: > + while (x) > + x = foo (x); > +} > > Jakub >