diff mbox

Fix PR78343

Message ID alpine.LSU.2.11.1611281146040.5294@t29.fhfr.qr
State New
Headers show

Commit Message

Richard Biener Nov. 28, 2016, 10:47 a.m. UTC 
On Mon, 28 Nov 2016, Christophe Lyon wrote:

> Hi Richard,
> 
> 
> On 25 November 2016 at 11:20, Richard Biener <rguenther@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  <rguenther@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  <rguenther@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.


> (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;
> >      }
> 
>
diff mbox

Patch

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];