| Message ID | 1330485140.4317.11.camel@gnopaine |
|---|---|
| State | New |
| Headers | show |
On Wed, Feb 29, 2012 at 4:12 AM, William J. Schmidt <wschmidt@linux.vnet.ibm.com> wrote: > This patch fixes PR52424 by pushing a missing marker onto > const_and_copies_stack before calling dom_thread_across_edge. This bug > has resulted in lost copy propagation opportunities in the presence of > edge threading. > > Bootstrapped and tested with no regressions on powerpc64-linux-gnu. I'm > waiting on Jiangning Liu to verify the patch fixes his performance > concern. Provided it does, is this OK for trunk? Ok. > Also, this bug has apparently been there for a long time. Should we > consider backporting the fix to 4.6 and/or 4.5? It's even present on the 4.1 branch, so I guess it has been there forever. Not worth backporting IMHO. Thanks, Richard. > Thanks, > Bill > > > 2012-02-28 Bill Schmidt <wschmidt@linux.vnet.ibm.com> > > PR tree-optimization/52424 > * tree-ssa-dom.c (dom_opt_leave_block): Push a marker before > calling dom_thread_across_edge. > > > Index: gcc/tree-ssa-dom.c > =================================================================== > --- gcc/tree-ssa-dom.c (revision 184625) > +++ gcc/tree-ssa-dom.c (working copy) > @@ -1779,6 +1779,9 @@ dom_opt_leave_block (struct dom_walk_data *walk_da > && (single_succ_edge (bb)->flags & EDGE_ABNORMAL) == 0 > && potentially_threadable_block (single_succ (bb))) > { > + /* Push a marker on the stack, which thread_across_edge expects > + and will remove. */ > + VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE); > dom_thread_across_edge (walk_data, single_succ_edge (bb)); > } > else if ((last = last_stmt (bb)) > >
Index: gcc/tree-ssa-dom.c =================================================================== --- gcc/tree-ssa-dom.c (revision 184625) +++ gcc/tree-ssa-dom.c (working copy) @@ -1779,6 +1779,9 @@ dom_opt_leave_block (struct dom_walk_data *walk_da && (single_succ_edge (bb)->flags & EDGE_ABNORMAL) == 0 && potentially_threadable_block (single_succ (bb))) { + /* Push a marker on the stack, which thread_across_edge expects + and will remove. */ + VEC_safe_push (tree, heap, const_and_copies_stack, NULL_TREE); dom_thread_across_edge (walk_data, single_succ_edge (bb)); } else if ((last = last_stmt (bb))