On Mon, 28 Nov 2016, Christophe Lyon wrote: > Hi Richard, > > > On 25 November 2016 at 11:20, Richard Biener <rguent...@suse.de> wrote: > > On Thu, 24 Nov 2016, Richard Biener wrote: > > > >> > >> I am testing the following patch for an optimization regression where > >> a loop made dead by final value replacement was made used again by > >> DOM 20 passes later. The real issue here is that we do not get rid > >> of dead loops until very late so this patch makes sure to do that. > >> We could schedule it later (but better no later than unrolling > >> as that might expose a pretty inefficient way of removing a dead loop). > >> > >> Bootstrap and regtest running on x86_64-unknown-linux-gnu. > > > > As expected some testcases need adjustment, thus applied as follows. > > > > Richard. > > > > 2016-11-24 Richard Biener <rguent...@suse.de> > > > > PR tree-optimization/78343 > > * passes.def: Add CD-DCE pass after loop splitting. > > * tree-ssa-dce.c (find_obviously_necessary_stmts): Move > > SCEV init/finalize ... > > (perform_tree_ssa_dce): ... here. Deal with being > > executed inside the loop pipeline in aggressive mode. > > > > * gcc.dg/tree-ssa/sccp-2.c: New testcase. > > * gcc.dg/autopar/uns-outer-6.c: Adjust. > > * gcc.dg/tree-ssa/20030808-1.c: Likewise. > > * gcc.dg/tree-ssa/20040305-1.c: Likewise. > > * gcc.dg/vect/pr38529.c: Likewise. > > > > But now, I am seeing failures on: > gcc.dg/tree-ssa/20030808-1.c scan-tree-dump-times cddce3 "->code" 0 > gcc.dg/tree-ssa/20030808-1.c scan-tree-dump-times cddce3 "if " 0 > gcc.dg/tree-ssa/20040305-1.c scan-tree-dump-times cddce3 "if " 2 > because the dump file does not exist.
Bah. Fixed as follows. 2016-11-28 Richard Biener <rguent...@suse.de> PR tree-optimization/78343 * gcc.dg/tree-ssa/20030808-1.c: Fix dump to generate. * gcc.dg/tree-ssa/20040305-1.c: Likewise. Index: gcc/testsuite/gcc.dg/tree-ssa/20030808-1.c =================================================================== --- gcc/testsuite/gcc.dg/tree-ssa/20030808-1.c (revision 242908) +++ gcc/testsuite/gcc.dg/tree-ssa/20030808-1.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O1 -fdump-tree-cddce2" } */ +/* { dg-options "-O1 -fdump-tree-cddce3" } */ extern void abort (void); Index: gcc/testsuite/gcc.dg/tree-ssa/20040305-1.c =================================================================== --- gcc/testsuite/gcc.dg/tree-ssa/20040305-1.c (revision 242908) +++ gcc/testsuite/gcc.dg/tree-ssa/20040305-1.c (working copy) @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-O2 -fdump-tree-cddce2 -fdump-tree-forwprop1-details" } */ +/* { dg-options "-O2 -fdump-tree-cddce3 -fdump-tree-forwprop1-details" } */ int abarney[2]; int afred[1]; > (on aarch64 and arm targets) > > Christophe > > > > diff --git a/gcc/passes.def b/gcc/passes.def > > index 2a470a7..2fa682b 100644 > > --- a/gcc/passes.def > > +++ b/gcc/passes.def > > @@ -271,6 +271,9 @@ along with GCC; see the file COPYING3. If not see > > NEXT_PASS (pass_tree_unswitch); > > NEXT_PASS (pass_scev_cprop); > > NEXT_PASS (pass_loop_split); > > + /* All unswitching, final value replacement and splitting can > > expose > > + empty loops. Remove them now. */ > > + NEXT_PASS (pass_cd_dce); > > NEXT_PASS (pass_record_bounds); > > NEXT_PASS (pass_loop_distribution); > > NEXT_PASS (pass_copy_prop); > > diff --git a/gcc/testsuite/gcc.dg/autopar/uns-outer-6.c > > b/gcc/testsuite/gcc.dg/autopar/uns-outer-6.c > > index dc2870b..5af60b0 100644 > > --- a/gcc/testsuite/gcc.dg/autopar/uns-outer-6.c > > +++ b/gcc/testsuite/gcc.dg/autopar/uns-outer-6.c > > @@ -25,7 +25,7 @@ parloop (int N) > > for (i = 0; i < N; i++) > > { > > for (j = 0; j < N; j++) > > - y[i]=x[i][j]; > > + y[i] += x[i][j]; > > sum += y[i]; > > } > > g_sum = sum; > > @@ -46,6 +46,10 @@ main (void) > > > > > > /* Check that outer loop is parallelized. */ > > +/* This fails because we have > > + FAILED: data dependencies exist across iterations > > + > > + > > /* { dg-final { scan-tree-dump-times "parallelizing outer loop" 1 > > "parloops2" } } */ > > /* { dg-final { scan-tree-dump-times "parallelizing inner loop" 0 > > "parloops2" } } */ > > /* { dg-final { scan-tree-dump-times "loopfn" 4 "optimized" } } */ > > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/20030808-1.c > > b/gcc/testsuite/gcc.dg/tree-ssa/20030808-1.c > > index 7cc5404..cda86a7 100644 > > --- a/gcc/testsuite/gcc.dg/tree-ssa/20030808-1.c > > +++ b/gcc/testsuite/gcc.dg/tree-ssa/20030808-1.c > > @@ -33,8 +33,8 @@ delete_dead_jumptables () > > /* There should be no loads of ->code. If any exist, then we failed to > > optimize away all the IF statements and the statements feeding > > their conditions. */ > > -/* { dg-final { scan-tree-dump-times "->code" 0 "cddce2"} } */ > > +/* { dg-final { scan-tree-dump-times "->code" 0 "cddce3"} } */ > > > > /* There should be no IF statements. */ > > -/* { dg-final { scan-tree-dump-times "if " 0 "cddce2"} } */ > > +/* { dg-final { scan-tree-dump-times "if " 0 "cddce3"} } */ > > > > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/20040305-1.c > > b/gcc/testsuite/gcc.dg/tree-ssa/20040305-1.c > > index 501e28c..d1a9af8 100644 > > --- a/gcc/testsuite/gcc.dg/tree-ssa/20040305-1.c > > +++ b/gcc/testsuite/gcc.dg/tree-ssa/20040305-1.c > > @@ -27,4 +27,4 @@ void foo(int edx, int eax) > > > > /* After cddce we should have two IF statements remaining as the other > > two tests can be threaded. */ > > -/* { dg-final { scan-tree-dump-times "if " 2 "cddce2"} } */ > > +/* { dg-final { scan-tree-dump-times "if " 2 "cddce3"} } */ > > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/sccp-2.c > > b/gcc/testsuite/gcc.dg/tree-ssa/sccp-2.c > > new file mode 100644 > > index 0000000..099b281 > > --- /dev/null > > +++ b/gcc/testsuite/gcc.dg/tree-ssa/sccp-2.c > > @@ -0,0 +1,15 @@ > > +/* { dg-do compile } */ > > +/* { dg-options "-O2 -fdump-tree-optimized" } */ > > + > > +unsigned int > > +test(unsigned int quant) > > +{ > > + unsigned int sum = 0; > > + for (unsigned int i = 0; i < quant; ++i) > > + sum += quant; > > + return sum; > > +} > > + > > +/* A single basic-block should remain (computing and > > + returning quant * quant). */ > > +/* { dg-final { scan-tree-dump-times "bb" 1 "optimized" } } */ > > diff --git a/gcc/testsuite/gcc.dg/vect/pr38529.c > > b/gcc/testsuite/gcc.dg/vect/pr38529.c > > index 171adeb..9b5919d 100644 > > --- a/gcc/testsuite/gcc.dg/vect/pr38529.c > > +++ b/gcc/testsuite/gcc.dg/vect/pr38529.c > > @@ -11,7 +11,3 @@ void foo() > > for (j = 0; j < 17; ++j) > > a[i] = 0; > > } > > - > > -/* { dg-final { scan-tree-dump-times "OUTER LOOP VECTORIZED" 1 "vect" } } > > */ > > - > > - > > diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c > > index 7b9814e..50b5eef 100644 > > --- a/gcc/tree-ssa-dce.c > > +++ b/gcc/tree-ssa-dce.c > > @@ -400,7 +400,6 @@ find_obviously_necessary_stmts (bool aggressive) > > if (aggressive) > > { > > struct loop *loop; > > - scev_initialize (); > > if (mark_irreducible_loops ()) > > FOR_EACH_BB_FN (bb, cfun) > > { > > @@ -423,7 +422,6 @@ find_obviously_necessary_stmts (bool aggressive) > > fprintf (dump_file, "can not prove finiteness of loop %i\n", > > loop->num); > > mark_control_dependent_edges_necessary (loop->latch, false); > > } > > - scev_finalize (); > > } > > } > > > > @@ -1567,9 +1565,13 @@ perform_tree_ssa_dce (bool aggressive) > > /* Preheaders are needed for SCEV to work. > > Simple lateches and recorded exits improve chances that loop will > > proved to be finite in testcases such as in loop-15.c and loop-24.c > > */ > > - if (aggressive) > > - loop_optimizer_init (LOOPS_NORMAL > > - | LOOPS_HAVE_RECORDED_EXITS); > > + bool in_loop_pipeline = scev_initialized_p (); > > + if (aggressive && ! in_loop_pipeline) > > + { > > + scev_initialize (); > > + loop_optimizer_init (LOOPS_NORMAL > > + | LOOPS_HAVE_RECORDED_EXITS); > > + } > > > > tree_dce_init (aggressive); > > > > @@ -1588,8 +1590,11 @@ perform_tree_ssa_dce (bool aggressive) > > > > find_obviously_necessary_stmts (aggressive); > > > > - if (aggressive) > > - loop_optimizer_finalize (); > > + if (aggressive && ! in_loop_pipeline) > > + { > > + loop_optimizer_finalize (); > > + scev_finalize (); > > + } > > > > longest_chain = 0; > > total_chain = 0; > > @@ -1623,7 +1628,7 @@ perform_tree_ssa_dce (bool aggressive) > > if (something_changed) > > { > > free_numbers_of_iterations_estimates (cfun); > > - if (scev_initialized_p ()) > > + if (in_loop_pipeline) > > scev_reset (); > > return TODO_update_ssa | TODO_cleanup_cfg; > > } > > -- Richard Biener <rguent...@suse.de> SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)