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Re: [gomp4 simd, RFC] Simple fix to override vectorization cost estimation.


ok, got it.
I'm not sure if C/C++ and FORTRAN are enough?


        * common.opt: Added new option -fsimd-cost-model
        * tree-vectorizer.h (unlimited_cost_model): Interface update
        to rely on particular loop info
        * tree-vect-data-refs.c (vect_peeling_hash_insert): Update to
        unlimited_cost_model call according to new interface
        (vect_peeling_hash_choose_best_peeling): Ditto
        (vect_enhance_data_refs_alignment): Ditto
        * tree-vect-slp.c: Ditto
        * tree-vect-loop.c (vect_estimate_min_profitable_iters): Ditto
        plus issue a warning in case cost model overrides users' directive
        * c-family/c.opt: add openmp-simd warning
        * fortran/lang.opt: Ditto


diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index 0026683..84911a0 100644
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -592,6 +592,10 @@ Wold-style-definition
 C ObjC Var(warn_old_style_definition) Warning
 Warn if an old-style parameter definition is used

+Wopenmp-simd
+C C++ Var(openmp_simd) Warning
+Warn about omp simd construct is overridden by cost model
+
 Woverlength-strings
 C ObjC C++ ObjC++ Var(warn_overlength_strings) Warning
LangEnabledBy(C ObjC C++ ObjC++,Wpedantic)
 Warn if a string is longer than the maximum portable length specified
by the standard
diff --git a/gcc/common.opt b/gcc/common.opt
index d5971df..9fab3ae 100644
--- a/gcc/common.opt
+++ b/gcc/common.opt
@@ -2296,6 +2296,10 @@ fvect-cost-model=
 Common Joined RejectNegative Enum(vect_cost_model)
Var(flag_vect_cost_model) Init(VECT_COST_MODEL_DEFAULT)
 Specifies the cost model for vectorization

+fsimd-cost-model=
+Common Joined RejectNegative Enum(vect_cost_model)
Var(flag_simd_cost_model) Init(VECT_COST_MODEL_DEFAULT)
+Specifies the cost model for vectorization in loops marked with omp simd
+
 Enum
 Name(vect_cost_model) Type(enum vect_cost_model) UnknownError(unknown
vectorizer cost model %qs)

diff --git a/gcc/fortran/lang.opt b/gcc/fortran/lang.opt
index 5e09cbd..3fc98a6 100644
--- a/gcc/fortran/lang.opt
+++ b/gcc/fortran/lang.opt
@@ -257,6 +257,10 @@ Wintrinsics-std
 Fortran Warning
 Warn on intrinsics not part of the selected standard

+Wopenmp-simd
+Fortran Warning
+Warn about omp simd construct is overridden by cost model
+
 Wreal-q-constant
 Fortran Warning
 Warn about real-literal-constants with 'q' exponent-letter
diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c
index 83d1f45..977db43 100644
--- a/gcc/tree-vect-data-refs.c
+++ b/gcc/tree-vect-data-refs.c
@@ -1090,7 +1090,8 @@ vect_peeling_hash_insert (loop_vec_info
loop_vinfo, struct data_reference *dr,
       *new_slot = slot;
     }

-  if (!supportable_dr_alignment && unlimited_cost_model ())
+  if (!supportable_dr_alignment
+      && unlimited_cost_model (LOOP_VINFO_LOOP (loop_vinfo)))
     slot->count += VECT_MAX_COST;
 }

@@ -1200,7 +1201,7 @@ vect_peeling_hash_choose_best_peeling
(loop_vec_info loop_vinfo,
    res.peel_info.dr = NULL;
    res.body_cost_vec = stmt_vector_for_cost ();

-   if (!unlimited_cost_model ())
+   if (!unlimited_cost_model (LOOP_VINFO_LOOP (loop_vinfo)))
      {
        res.inside_cost = INT_MAX;
        res.outside_cost = INT_MAX;
@@ -1429,7 +1430,7 @@ vect_enhance_data_refs_alignment (loop_vec_info
loop_vinfo)
                  vectorization factor.
                  We do this automtically for cost model, since we
calculate cost
                  for every peeling option.  */
-              if (unlimited_cost_model ())
+              if (unlimited_cost_model (LOOP_VINFO_LOOP (loop_vinfo)))
                 possible_npeel_number = vf /nelements;

               /* Handle the aligned case. We may decide to align some other
@@ -1437,7 +1438,7 @@ vect_enhance_data_refs_alignment (loop_vec_info
loop_vinfo)
               if (DR_MISALIGNMENT (dr) == 0)
                 {
                   npeel_tmp = 0;
-                  if (unlimited_cost_model ())
+                  if (unlimited_cost_model (LOOP_VINFO_LOOP (loop_vinfo)))
                     possible_npeel_number++;
                 }

diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 86ebbd2..d360f43 100644
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -2696,7 +2696,7 @@ vect_estimate_min_profitable_iters
(loop_vec_info loop_vinfo,
   void *target_cost_data = LOOP_VINFO_TARGET_COST_DATA (loop_vinfo);

   /* Cost model disabled.  */
-  if (unlimited_cost_model ())
+  if (unlimited_cost_model (LOOP_VINFO_LOOP (loop_vinfo)))
     {
       dump_printf_loc (MSG_NOTE, vect_location, "cost model disabled.\n");
       *ret_min_profitable_niters = 0;
@@ -2929,6 +2929,12 @@ vect_estimate_min_profitable_iters
(loop_vec_info loop_vinfo,
   /* vector version will never be profitable.  */
   else
     {
+      if (LOOP_VINFO_LOOP (loop_vinfo)->force_vect)
+        {
+          warning (OPT_Wopenmp_simd, "Vectorization did not happen
for the loop ",
+                   "labeled as simd");
+        }
+
       if (dump_enabled_p ())
         dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
                         "cost model: the vector iteration cost = %d "
diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 247bdfd..4b25964 100644
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -2171,7 +2171,7 @@ vect_slp_analyze_bb_1 (basic_block bb)
     }

   /* Cost model: check if the vectorization is worthwhile.  */
-  if (!unlimited_cost_model ()
+  if (!unlimited_cost_model (NULL)
       && !vect_bb_vectorization_profitable_p (bb_vinfo))
     {
       if (dump_enabled_p ())
diff --git a/gcc/tree-vectorizer.h b/gcc/tree-vectorizer.h
index a6c5b59..fd255db 100644
--- a/gcc/tree-vectorizer.h
+++ b/gcc/tree-vectorizer.h
@@ -919,9 +919,12 @@ known_alignment_for_access_p (struct
data_reference *data_ref_info)

 /* Return true if the vect cost model is unlimited.  */
 static inline bool
-unlimited_cost_model ()
+unlimited_cost_model (loop_p loop)
 {
-  return flag_vect_cost_model == VECT_COST_MODEL_UNLIMITED;
+  return (flag_vect_cost_model == VECT_COST_MODEL_UNLIMITED
+          || (loop != NULL
+              && loop->force_vect
+              && flag_simd_cost_model == VECT_COST_MODEL_UNLIMITED));
 }

 /* Source location */

On Tue, Nov 19, 2013 at 6:42 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Tue, Nov 19, 2013 at 06:39:48PM +0400, Sergey Ostanevich wrote:
>> > pedwarn isn't really desirable for this, you want just warning,
>> > but some warning you can actually also turn off.
>> > -Wopenmp-simd (and we'd use it also when we ignore #pragma omp declare simd
>> > because it wasn't useful/desirable).
>>
>> consider a user is interested in enabling warning-as-error for this case?
>
> -Werror=openmp-simd will work then, this works for any named warnings.
>
>> can we disable the pedwarn the same way?
>
> pedwarn is for pedantic warnings, no standard says that #pragma omp simd
> must be vectorized, or that #pragma omp simd or #pragma omp declare simd
> is anything but an optimization hint, so pedwarn isn't what you are looking
> for.
>
>         Jakub


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