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Re: [PATCH] Hoist loop invariant statements containing data refs with zero-step during loop-versioning in vectorization.


I tested this case with -fno-tree-loop-im and -fno-tree-pre, and it
seems that GCC could hoist j+1 outside of the i loop:

t3.c:5:5: note: hoisting out of the vectorized loop: _10 = (sizetype) j_25;
t3.c:5:5: note: hoisting out of the vectorized loop: _11 = _10 + 1;
t3.c:5:5: note: hoisting out of the vectorized loop: _12 = _11 * 4;
t3.c:5:5: note: hoisting out of the vectorized loop: _14 = b_13(D) + _12;
t3.c:5:5: note: hoisting out of the vectorized loop: _15 = *_14;
t3.c:5:5: note: hoisting out of the vectorized loop: _16 = _15 + 1;


But your suggestion is still nice as it can remove a branch and make
the code more brief. I have updated the patch and also included the
nested loop example into the test case.

Thank you!


Cong



diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 8a38316..2637309 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2013-10-15  Cong Hou  <congh@google.com>
+
+ * tree-vect-loop-manip.c (vect_loop_versioning): Hoist loop invariant
+ statement that contains data refs with zero-step.
+
 2013-10-14  David Malcolm  <dmalcolm@redhat.com>

  * dumpfile.h (gcc::dump_manager): New class, to hold state
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 075d071..9d0f4a5 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2013-10-15  Cong Hou  <congh@google.com>
+
+ * gcc.dg/vect/pr58508.c: New test.
+
 2013-10-14  Tobias Burnus  <burnus@net-b.de>

  PR fortran/58658
diff --git a/gcc/testsuite/gcc.dg/vect/pr58508.c
b/gcc/testsuite/gcc.dg/vect/pr58508.c
new file mode 100644
index 0000000..6484a65
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr58508.c
@@ -0,0 +1,70 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-vectorize -fdump-tree-vect-details" } */
+
+
+/* The GCC vectorizer generates loop versioning for the following loop
+   since there may exist aliasing between A and B.  The predicate checks
+   if A may alias with B across all iterations.  Then for the loop in
+   the true body, we can assert that *B is a loop invariant so that
+   we can hoist the load of *B before the loop body.  */
+
+void test1 (int* a, int* b)
+{
+  int i;
+  for (i = 0; i < 100000; ++i)
+    a[i] = *b + 1;
+}
+
+/* A test case with nested loops.  The load of b[j+1] in the inner
+   loop should be hoisted.  */
+
+void test2 (int* a, int* b)
+{
+  int i, j;
+  for (j = 0; j < 100000; ++j)
+    for (i = 0; i < 100000; ++i)
+      a[i] = b[j+1] + 1;
+}
+
+/* A test case with ifcvt transformation.  */
+
+void test3 (int* a, int* b)
+{
+  int i, t;
+  for (i = 0; i < 10000; ++i)
+    {
+      if (*b > 0)
+ t = *b * 2;
+      else
+ t = *b / 2;
+      a[i] = t;
+    }
+}
+
+/* A test case in which the store in the loop can be moved outside
+   in the versioned loop with alias checks.  Note this loop won't
+   be vectorized.  */
+
+void test4 (int* a, int* b)
+{
+  int i;
+  for (i = 0; i < 100000; ++i)
+    *a += b[i];
+}
+
+/* A test case in which the load and store in the loop to b
+   can be moved outside in the versioned loop with alias checks.
+   Note this loop won't be vectorized.  */
+
+void test5 (int* a, int* b)
+{
+  int i;
+  for (i = 0; i < 100000; ++i)
+    {
+      *b += a[i];
+      a[i] = *b;
+    }
+}
+
+/* { dg-final { scan-tree-dump-times "hoist" 8 "vect" } } */
+/* { dg-final { cleanup-tree-dump "vect" } } */
diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c
index 574446a..1cc563c 100644
--- a/gcc/tree-vect-loop-manip.c
+++ b/gcc/tree-vect-loop-manip.c
@@ -2477,6 +2477,73 @@ vect_loop_versioning (loop_vec_info loop_vinfo,
       adjust_phi_and_debug_stmts (orig_phi, e, PHI_RESULT (new_phi));
     }

+
+  /* Extract load statements on memrefs with zero-stride accesses.  */
+
+  if (LOOP_REQUIRES_VERSIONING_FOR_ALIAS (loop_vinfo))
+    {
+      /* In the loop body, we iterate each statement to check if it is a load.
+ Then we check the DR_STEP of the data reference.  If DR_STEP is zero,
+ then we will hoist the load statement to the loop preheader.  */
+
+      basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
+      int nbbs = loop->num_nodes;
+
+      for (int i = 0; i < nbbs; ++i)
+ {
+  for (gimple_stmt_iterator si = gsi_start_bb (bbs[i]);
+       !gsi_end_p (si);)
+    {
+      gimple stmt = gsi_stmt (si);
+      stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
+      struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info);
+
+      if (is_gimple_assign (stmt)
+  && (!dr
+      || (DR_IS_READ (dr) && integer_zerop (DR_STEP (dr)))))
+ {
+  bool hoist = true;
+  ssa_op_iter iter;
+  tree var;
+
+  /* We hoist a statement if all SSA uses in it are defined
+     outside of the loop.  */
+  FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE)
+    {
+      gimple def = SSA_NAME_DEF_STMT (var);
+      if (!gimple_nop_p (def)
+  && flow_bb_inside_loop_p (loop, gimple_bb (def)))
+ {
+  hoist = false;
+  break;
+ }
+    }
+
+  if (hoist)
+    {
+      if (dr)
+ gimple_set_vuse (stmt, NULL);
+
+      gsi_remove (&si, false);
+      gsi_insert_on_edge_immediate (loop_preheader_edge (loop),
+    stmt);
+
+      if (dump_enabled_p ())
+ {
+  dump_printf_loc
+      (MSG_NOTE, vect_location,
+       "hoisting out of the vectorized loop: ");
+  dump_gimple_stmt (MSG_NOTE, TDF_SLIM, stmt, 0);
+  dump_printf (MSG_NOTE, "\n");
+ }
+      continue;
+    }
+ }
+      gsi_next (&si);
+    }
+ }
+    }
+
   /* End loop-exit-fixes after versioning.  */

   if (cond_expr_stmt_list)




^^^^^^^^^^^^^^^END OF PATCH^^^^^^^^^^^^^^^^^^^




On Thu, Oct 17, 2013 at 2:17 AM, Richard Biener <rguenther@suse.de> wrote:
> On Wed, 16 Oct 2013, Cong Hou wrote:
>
>> On Wed, Oct 16, 2013 at 2:02 AM, Richard Biener <rguenther@suse.de> wrote:
>> > On Tue, 15 Oct 2013, Cong Hou wrote:
>> >
>> >> Thank you for your reminder, Jeff! I just noticed Richard's comment. I
>> >> have modified the patch according to that.
>> >>
>> >> The new patch is attached.
>> >
>> > (posting patches inline is easier for review, now you have to deal
>> > with no quoting markers ;))
>> >
>> > Comments inline.
>> >
>> > diff --git a/gcc/ChangeLog b/gcc/ChangeLog
>> > index 8a38316..2637309 100644
>> > --- a/gcc/ChangeLog
>> > +++ b/gcc/ChangeLog
>> > @@ -1,3 +1,8 @@
>> > +2013-10-15  Cong Hou  <congh@google.com>
>> > +
>> > +       * tree-vect-loop-manip.c (vect_loop_versioning): Hoist loop invariant
>> > +       statement that contains data refs with zero-step.
>> > +
>> >  2013-10-14  David Malcolm  <dmalcolm@redhat.com>
>> >
>> >         * dumpfile.h (gcc::dump_manager): New class, to hold state
>> > diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
>> > index 075d071..9d0f4a5 100644
>> > --- a/gcc/testsuite/ChangeLog
>> > +++ b/gcc/testsuite/ChangeLog
>> > @@ -1,3 +1,7 @@
>> > +2013-10-15  Cong Hou  <congh@google.com>
>> > +
>> > +       * gcc.dg/vect/pr58508.c: New test.
>> > +
>> >  2013-10-14  Tobias Burnus  <burnus@net-b.de>
>> >
>> >         PR fortran/58658
>> > diff --git a/gcc/testsuite/gcc.dg/vect/pr58508.c b/gcc/testsuite/gcc.dg/vect/pr58508.c
>> > new file mode 100644
>> > index 0000000..cb22b50
>> > --- /dev/null
>> > +++ b/gcc/testsuite/gcc.dg/vect/pr58508.c
>> > @@ -0,0 +1,20 @@
>> > +/* { dg-do compile } */
>> > +/* { dg-options "-O2 -ftree-vectorize -fdump-tree-vect-details" } */
>> > +
>> > +
>> > +/* The GCC vectorizer generates loop versioning for the following loop
>> > +   since there may exist aliasing between A and B.  The predicate checks
>> > +   if A may alias with B across all iterations.  Then for the loop in
>> > +   the true body, we can assert that *B is a loop invariant so that
>> > +   we can hoist the load of *B before the loop body.  */
>> > +
>> > +void foo (int* a, int* b)
>> > +{
>> > +  int i;
>> > +  for (i = 0; i < 100000; ++i)
>> > +    a[i] = *b + 1;
>> > +}
>> > +
>> > +
>> > +/* { dg-final { scan-tree-dump-times "hoist" 2 "vect" } } */
>> > +/* { dg-final { cleanup-tree-dump "vect" } } */
>> > diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c
>> > index 574446a..f4fdec2 100644
>> > --- a/gcc/tree-vect-loop-manip.c
>> > +++ b/gcc/tree-vect-loop-manip.c
>> > @@ -2477,6 +2477,92 @@ vect_loop_versioning (loop_vec_info loop_vinfo,
>> >        adjust_phi_and_debug_stmts (orig_phi, e, PHI_RESULT (new_phi));
>> >      }
>> >
>> >
>> > Note that applying this kind of transform at this point invalidates
>> > some of the earlier analysis the vectorizer performed (namely the
>> > def-kind which now effectively gets vect_external_def from
>> > vect_internal_def).  In this case it doesn't seem to cause any
>> > issues (we re-compute the def-kind everytime we need it (how wasteful)).
>> >
>> > +  /* Extract load and store statements on pointers with zero-stride
>> > +     accesses.  */
>> > +  if (LOOP_REQUIRES_VERSIONING_FOR_ALIAS (loop_vinfo))
>> > +    {
>> > +      /* In the loop body, we iterate each statement to check if it is a load
>> > +        or store.  Then we check the DR_STEP of the data reference.  If
>> > +        DR_STEP is zero, then we will hoist the load statement to the loop
>> > +        preheader, and move the store statement to the loop exit.  */
>> >
>> > We don't move the store yet.  Micha has a patch pending that enables
>> > vectorization of zero-step stores.
>> >
>> > +      for (gimple_stmt_iterator si = gsi_start_bb (loop->header);
>> > +          !gsi_end_p (si);)
>> >
>> > While technically ok now (vectorized loops contain a single basic block)
>> > please use LOOP_VINFO_BBS () to get at the vector of basic-blcoks
>> > and iterate over them like other code does.
>>
>>
>> Have done it.
>>
>>
>> >
>> > +       {
>> > +         gimple stmt = gsi_stmt (si);
>> > +         stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
>> > +         struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info);
>> > +
>> > +         if (dr && integer_zerop (DR_STEP (dr)))
>> > +           {
>> > +             if (DR_IS_READ (dr))
>> > +               {
>> > +                 if (dump_enabled_p ())
>> > +                   {
>> > +                     dump_printf_loc
>> > +                         (MSG_NOTE, vect_location,
>> > +                          "hoist the statement to outside of the loop ");
>> >
>> > "hoisting out of the vectorized loop: "
>> >
>> > +                     dump_gimple_stmt (MSG_NOTE, TDF_SLIM, stmt, 0);
>> > +                     dump_printf (MSG_NOTE, "\n");
>> > +                   }
>> > +
>> > +                 gsi_remove (&si, false);
>> > +                 gsi_insert_on_edge_immediate (loop_preheader_edge (loop), stmt);
>> >
>> > Note that this will result in a bogus VUSE on the stmt at this point which
>> > will be only fixed because of implementation details of loop versioning.
>> > Either get the correct VUSE from the loop header virtual PHI node
>> > preheader edge (if there is none then the current VUSE is the correct one
>> > to use) or clear it.
>>
>>
>> I just cleared the VUSE since I noticed that after the vectorization
>> pass the correct VUSE is reassigned to the load.
>>
>>
>> >
>> > +               }
>> > +             /* TODO: We also consider vectorizing loops containing zero-step
>> > +                data refs as writes.  For example:
>> > +
>> > +                int a[N], *s;
>> > +                for (i = 0; i < N; i++)
>> > +                  *s += a[i];
>> > +
>> > +                In this case the write to *s can be also moved after the
>> > +                loop.  */
>> >
>> > Note that you then invalidate even more vectorizer analysis - you
>> > basically introduce a scalar reduction (you have to add a PHI node).
>> > Which means that the transform has to happen elsewhere.
>> >
>> > As Jakub now tries with if-conversion this would also be a candidate
>> > for applying the loop versioning before even starting the rest of the
>> > vectorizer analysis code.
>> >
>> > That said, I'd remove the TODO at this point because it's clearly not
>> > possible to implement just here ;)
>>
>>
>> Yes. This comment is removed.
>>
>>
>> >
>> > +             continue;
>> > +           }
>> > +         else if (!dr)
>> > +         {
>> > +           bool hoist = true;
>> > +           for (size_t i = 0; i < gimple_num_ops (stmt); i++)
>> >
>> > You are checking all kinds of statements, including assignments
>> > of which you are also checking the LHS ... restricting to
>> > assignments you can start walking at i = 1.
>>
>>
>> Done.
>>
>>
>> >
>> > +             {
>> > +               tree op = gimple_op (stmt, i);
>> > +               if (TREE_CODE (op) == INTEGER_CST
>> > +                   || TREE_CODE (op) == REAL_CST)
>> >
>> > There are other constants as well - just check
>> >
>> >                 if (is_gimple_min_invariant (op))
>> >
>> > +                 continue;
>> > +               if (TREE_CODE (op) == SSA_NAME)
>> > +                 {
>> > +                   gimple def = SSA_NAME_DEF_STMT (op);
>> > +                   if (def == stmt
>> >
>> > with starting at op 1 you can drop this.
>> >
>> > +                       || gimple_nop_p (def)
>> > +                       || !flow_bb_inside_loop_p (loop, gimple_bb (def)))
>> > +                     continue;
>> > +                 }
>> >
>> > Note that you fail to hoist if-converted code this way because
>> > op1 of
>> >
>> >    name_1 = a_2 < b_4 ? x_5 : y_6;
>> >
>> > is 'a_2 < b_4', a tree expression and not an SSA name (ugh).  Maybe
>> > we don't care (it's just a missed optimization), but if you are
>> > restricting yourself to hoisting assignments without a data-ref
>> > then you can walk over SSA uses on the stmt (instead of over gimple
>> > ops) with
>> >
>> >                 FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_USE)
>> >
>> > which would automagically take care of that case.
>>
>>
>> I used FOR_EACH_SSA_TREE_OPERAND() here, and then I don't have to deal
>> with different constant types.
>>
>>
>> >
>> > Can you add a testcase which involves invariant if-conversion?
>> > Can you add a testcase with just an invariant store to make sure
>> > we don't wreck it?  Can you add a testcase with an invariant store
>> > and load (the reduction case), too?
>>
>>
>> The if-conversion case is added. But the current vectorizer will not
>> vectorize loops with stores to zero-stride memory access
>> (vect_analyze_loop() fails in this case). Are you sure to add the
>> testcase with this? (I still added two tests for those two cases).
>>
>>
>> >
>> > +               hoist = false;
>> > +               break;
>> > +             }
>> >
>> > For example you'll hoist all labels this way (no ops), as well as the
>> > loop exit GIMPLE_COND in case it's operands were loop invariant,
>> > breaking the CFG ... so please add && is_gimple_assign () to the
>> > if (!dr) check ;)
>>
>>
>> Done.
>>
>>
>> I appreciate your detailed comments! The new patch is pasted below
>> (since tabs cannot show here I also attached a text file with the
>> patch including tabs).
>
> (supposedly messed up on mine or your end somehow)
>
> It just occured to me that you have to verify that you can hoist
> the load, as for example with
>
> void test1 (int* a, int* b)
> {
>   int i, j;
>   for (j = 0; j < 100; ++j)
>     for (i = 0; i < 100000; ++i)
>       a[i] = b[j+1] + 1;
> }
>
> DR_STEP will be zero, but if you build with -fno-tree-loop-im
> -fno-tree-pre the stmt computing j+1 will still be in the i loop
> and thus you would need to move that as well.
>
> A way out is to double-check all SSA uses on the load as well,
> like you do on other assignments.  That is, combine both
> if arms under a single
>
>   if (is_gimple_assign (stmt)
>       && (!dr
>           || (DR_IS_READ (dr) && integer_zerop (DR_STEP (dr))))
>
> Thanks,
> Richard.
>
>
>>
>> thanks,
>> Cong
>>
>>
>>
>>
>> diff --git a/gcc/ChangeLog b/gcc/ChangeLog
>> index 8a38316..2637309 100644
>> --- a/gcc/ChangeLog
>> +++ b/gcc/ChangeLog
>> @@ -1,3 +1,8 @@
>> +2013-10-15  Cong Hou  <congh@google.com>
>> +
>> + * tree-vect-loop-manip.c (vect_loop_versioning): Hoist loop invariant
>> + statement that contains data refs with zero-step.
>> +
>>  2013-10-14  David Malcolm  <dmalcolm@redhat.com>
>>
>>   * dumpfile.h (gcc::dump_manager): New class, to hold state
>> diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
>> index 075d071..9d0f4a5 100644
>> --- a/gcc/testsuite/ChangeLog
>> +++ b/gcc/testsuite/ChangeLog
>> @@ -1,3 +1,7 @@
>> +2013-10-15  Cong Hou  <congh@google.com>
>> +
>> + * gcc.dg/vect/pr58508.c: New test.
>> +
>>  2013-10-14  Tobias Burnus  <burnus@net-b.de>
>>
>>   PR fortran/58658
>> diff --git a/gcc/testsuite/gcc.dg/vect/pr58508.c
>> b/gcc/testsuite/gcc.dg/vect/pr58508.c
>> new file mode 100644
>> index 0000000..a3f6a06
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.dg/vect/pr58508.c
>> @@ -0,0 +1,60 @@
>> +/* { dg-do compile } */
>> +/* { dg-options "-O2 -ftree-vectorize -fdump-tree-vect-details" } */
>> +
>> +
>> +/* The GCC vectorizer generates loop versioning for the following loop
>> +   since there may exist aliasing between A and B.  The predicate checks
>> +   if A may alias with B across all iterations.  Then for the loop in
>> +   the true body, we can assert that *B is a loop invariant so that
>> +   we can hoist the load of *B before the loop body.  */
>> +
>> +void test1 (int* a, int* b)
>> +{
>> +  int i;
>> +  for (i = 0; i < 100000; ++i)
>> +    a[i] = *b + 1;
>> +}
>> +
>> +
>> +/* A test case with ifcvt transformation.  */
>> +
>> +void test2 (int* a, int* b)
>> +{
>> +  int i, t;
>> +  for (i = 0; i < 10000; ++i)
>> +    {
>> +      if (*b > 0)
>> + t = *b * 2;
>> +      else
>> + t = *b / 2;
>> +      a[i] = t;
>> +    }
>> +}
>> +
>> +/* A test case in which the store in the loop can be moved outside
>> +   in the versioned loop with alias checks.  Note this loop won't
>> +   be vectorized.  */
>> +
>> +void test3 (int* a, int* b)
>> +{
>> +  int i;
>> +  for (i = 0; i < 100000; ++i)
>> +    *a += b[i];
>> +}
>> +
>> +/* A test case in which the load and store in the loop to b
>> +   can be moved outside in the versioned loop with alias checks.
>> +   Note this loop won't be vectorized.  */
>> +
>> +void test4 (int* a, int* b)
>> +{
>> +  int i;
>> +  for (i = 0; i < 100000; ++i)
>> +    {
>> +      *b += a[i];
>> +      a[i] = *b;
>> +    }
>> +}
>> +
>> +/* { dg-final { scan-tree-dump-times "hoist" 6 "vect" } } */
>> +/* { dg-final { cleanup-tree-dump "vect" } } */
>> diff --git a/gcc/tree-vect-loop-manip.c b/gcc/tree-vect-loop-manip.c
>> index 574446a..ff0403b 100644
>> --- a/gcc/tree-vect-loop-manip.c
>> +++ b/gcc/tree-vect-loop-manip.c
>> @@ -2477,6 +2477,88 @@ vect_loop_versioning (loop_vec_info loop_vinfo,
>>        adjust_phi_and_debug_stmts (orig_phi, e, PHI_RESULT (new_phi));
>>      }
>>
>> +
>> +  /* Extract load statements on memrefs with zero-stride accesses.  */
>> +
>> +  if (LOOP_REQUIRES_VERSIONING_FOR_ALIAS (loop_vinfo))
>> +    {
>> +      /* In the loop body, we iterate each statement to check if it is a load.
>> + Then we check the DR_STEP of the data reference.  If DR_STEP is zero,
>> + then we will hoist the load statement to the loop preheader.  */
>> +
>> +      basic_block *bbs = LOOP_VINFO_BBS (loop_vinfo);
>> +      int nbbs = loop->num_nodes;
>> +
>> +      for (int i = 0; i < nbbs; ++i)
>> + {
>> +  for (gimple_stmt_iterator si = gsi_start_bb (bbs[i]);
>> +       !gsi_end_p (si);)
>> +    {
>> +      gimple stmt = gsi_stmt (si);
>> +      stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
>> +      struct data_reference *dr = STMT_VINFO_DATA_REF (stmt_info);
>> +
>> +      if (dr && integer_zerop (DR_STEP (dr)))
>> + {
>> +  if (DR_IS_READ (dr))
>> +    {
>> +      if (dump_enabled_p ())
>> + {
>> +  dump_printf_loc
>> +      (MSG_NOTE, vect_location,
>> +       "hoisting out of the vectorized loop: ");
>> +  dump_gimple_stmt (MSG_NOTE, TDF_SLIM, stmt, 0);
>> +  dump_printf (MSG_NOTE, "\n");
>> + }
>> +
>> +      gimple_set_vuse (stmt, NULL);
>> +      gsi_remove (&si, false);
>> +      gsi_insert_on_edge_immediate (loop_preheader_edge (loop),
>> +    stmt);
>> +    }
>> +  continue;
>> + }
>> +      else if (!dr && is_gimple_assign (stmt))
>> + {
>> +  bool hoist = true;
>> +  ssa_op_iter iter;
>> +  tree var;
>> +
>> +  /* We hoist a statement if all SSA uses in it are defined
>> +     outside of the loop.  */
>> +  FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_USE)
>> +    {
>> +      gimple def = SSA_NAME_DEF_STMT (var);
>> +      if (!gimple_nop_p (def)
>> +  && flow_bb_inside_loop_p (loop, gimple_bb (def)))
>> + {
>> +  hoist = false;
>> +  break;
>> + }
>> +    }
>> +
>> +  if (hoist)
>> +    {
>> +      gsi_remove (&si, false);
>> +      gsi_insert_on_edge_immediate (loop_preheader_edge (loop),
>> +    stmt);
>> +
>> +      if (dump_enabled_p ())
>> + {
>> +  dump_printf_loc
>> +      (MSG_NOTE, vect_location,
>> +       "hoisting out of the vectorized loop: ");
>> +  dump_gimple_stmt (MSG_NOTE, TDF_SLIM, stmt, 0);
>> +  dump_printf (MSG_NOTE, "\n");
>> + }
>> +      continue;
>> +    }
>> + }
>> +      gsi_next (&si);
>> +    }
>> + }
>> +    }
>> +
>>    /* End loop-exit-fixes after versioning.  */
>>
>>    if (cond_expr_stmt_list)
>>
>>
>>
>>
>>
>> >
>> > +           if (hoist)
>> > +             {
>> > +               gsi_remove (&si, false);
>> > +               gsi_insert_on_edge_immediate (loop_preheader_edge (loop), stmt);
>> > +
>> > +               if (dump_enabled_p ())
>> > +                 {
>> > +                   dump_printf_loc
>> > +                       (MSG_NOTE, vect_location,
>> > +                        "hoist the statement to outside of the loop ");
>> > +                   dump_gimple_stmt (MSG_NOTE, TDF_SLIM, stmt, 0);
>> > +                   dump_printf (MSG_NOTE, "\n");
>> > +                 }
>> > +               continue;
>> > +             }
>> > +         }
>> > +         gsi_next (&si);
>> > +       }
>> > +    }
>> > +
>> >    /* End loop-exit-fixes after versioning.  */
>> >
>> >    if (cond_expr_stmt_list)
>> >
>> >>
>> >> thanks,
>> >> Cong
>> >>
>> >>
>> >> On Tue, Oct 15, 2013 at 12:33 PM, Jeff Law <law@redhat.com> wrote:
>> >> > On 10/14/13 17:31, Cong Hou wrote:
>> >> >>
>> >> >> Any comment on this patch?
>> >> >
>> >> > Richi replied in the BZ you opened.
>> >> >
>> >> > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58508
>> >> >
>> >> > Essentially he said emit the load on the edge rather than in the block
>> >> > itself.
>> >> > jeff
>> >> >
>>
>
> --
> Richard Biener <rguenther@suse.de>
> SUSE / SUSE Labs
> SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
> GF: Jeff Hawn, Jennifer Guild, Felix Imend

Attachment: patch-hoist.txt
Description: Text document


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