[Bug tree-optimization/50730] New: SLP vectorization confused by unrelated DRs

[Bug tree-optimization/50730] New: SLP vectorization confused by unrelated DRs

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50730

             Bug #: 50730
           Summary: SLP vectorization confused by unrelated DRs
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: rguenth@gcc.gnu.org
                CC: irar@gcc.gnu.org


The SLP vectorizer is confused by the aggregate store in

typedef __complex__ float Value;
struct A {
  Value a[16 / sizeof (Value)];
} __attribute__ ((aligned(16)));

A sum(A a, A b)
{
  a.a[0]+=b.a[0];
  a.a[1]+=b.a[1];
  return a;
}

when built with -O3 -fno-tree-sra:

<bb 2>:
  D.2130_11 = REALPART_EXPR <a.a[0]>;
  D.2131_12 = IMAGPART_EXPR <a.a[0]>;
  D.2132_13 = REALPART_EXPR <b.a[0]>;
  D.2133_14 = IMAGPART_EXPR <b.a[0]>;
  D.2134_15 = D.2130_11 + D.2132_13;
  D.2135_16 = D.2131_12 + D.2133_14;
  REALPART_EXPR <a.a[0]> = D.2134_15;
  IMAGPART_EXPR <a.a[0]> = D.2135_16;
  D.2136_17 = REALPART_EXPR <a.a[1]>;
  D.2137_18 = IMAGPART_EXPR <a.a[1]>;
  D.2138_19 = REALPART_EXPR <b.a[1]>;
  D.2139_20 = IMAGPART_EXPR <b.a[1]>;
  D.2140_21 = D.2136_17 + D.2138_19;
  D.2141_22 = D.2137_18 + D.2139_20;
  REALPART_EXPR <a.a[1]> = D.2140_21;
  IMAGPART_EXPR <a.a[1]> = D.2141_22;
  D.2119 = a;
  return D.2119;

but I don't see why SLP couldn't simply stop analyzing the BB when
it encounters a DR that it cannot build or handle.  The
previous instructions can be still vectorized.

If you put an unrelated volatile store at the end of any sequence
in a bb-slp testcase this reproduces as well.  The above testcase
will probably fail due to unsupported strided stores.

[Bug tree-optimization/50730] SLP vectorization confused by unrelated DRs

[irar at il dot ibm.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50730

Ira Rosen <irar at il dot ibm.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2011-10-16
                 CC|                            |irar at il dot ibm.com
     Ever Confirmed|0                           |1

--- Comment #1 from Ira Rosen <irar at il dot ibm.com> 2011-10-16 09:41:27 UTC ---
Tested only with the vectorizer tests.

Index: tree-vect-data-refs.c
===================================================================
--- tree-vect-data-refs.c       (revision 179789)
+++ tree-vect-data-refs.c       (working copy)
@@ -2524,7 +2524,7 @@ vect_analyze_data_refs (loop_vec_info lo
   VEC (data_reference_p, heap) *datarefs;
   struct data_reference *dr;
   tree scalar_type;
-  bool res;
+  bool res, stop_bb_analysis = false;

   if (vect_print_dump_info (REPORT_DETAILS))
     fprintf (vect_dump, "=== vect_analyze_data_refs ===\n");
@@ -2579,12 +2579,19 @@ vect_analyze_data_refs (loop_vec_info lo
         {
           if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS))
            fprintf (vect_dump, "not vectorized: unhandled data-ref ");
+
           return false;
         }

       stmt = DR_STMT (dr);
       stmt_info = vinfo_for_stmt (stmt);

+      if (stop_bb_analysis)
+        {
+          STMT_VINFO_VECTORIZABLE (stmt_info) = false;
+          continue;
+        }
+
       /* Check that analysis of the data-ref succeeded.  */
       if (!DR_BASE_ADDRESS (dr) || !DR_OFFSET (dr) || !DR_INIT (dr)
           || !DR_STEP (dr))
@@ -2595,6 +2602,13 @@ vect_analyze_data_refs (loop_vec_info lo
               print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM);
             }

+          if (bb_vinfo)
+            {
+              STMT_VINFO_VECTORIZABLE (stmt_info) = false;
+              stop_bb_analysis = true;
+              continue;
+            }
+
           return false;
         }

@@ -2603,7 +2617,15 @@ vect_analyze_data_refs (loop_vec_info lo
           if (vect_print_dump_info (REPORT_UNVECTORIZED_LOCATIONS))
             fprintf (vect_dump, "not vectorized: base addr of dr is a "
                      "constant");
-          return false;
+
+          if (bb_vinfo)
+            {
+              STMT_VINFO_VECTORIZABLE (stmt_info) = false;
+              stop_bb_analysis = true;
+              continue;
+            }
+
+           return false;
         }

       if (TREE_THIS_VOLATILE (DR_REF (dr)))
@@ -2613,6 +2635,14 @@ vect_analyze_data_refs (loop_vec_info lo
               fprintf (vect_dump, "not vectorized: volatile type ");
               print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM);
             }
+
+          if (bb_vinfo)
+            {
+              STMT_VINFO_VECTORIZABLE (stmt_info) = false;
+              stop_bb_analysis = true;
+              continue;
+            }
+
           return false;
         }

@@ -2628,6 +2658,14 @@ vect_analyze_data_refs (loop_vec_info lo
                        "exception ");
               print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM);
             }
+
+          if (bb_vinfo)
+            {
+              STMT_VINFO_VECTORIZABLE (stmt_info) = false;
+              stop_bb_analysis = true;
+              continue;
+            }
+
           return false;
         }

@@ -2745,6 +2783,14 @@ vect_analyze_data_refs (loop_vec_info lo
                        "not vectorized: more than one data ref in stmt: ");
               print_gimple_stmt (vect_dump, stmt, 0, TDF_SLIM);
             }
+
+          if (bb_vinfo)
+            {
+              STMT_VINFO_VECTORIZABLE (stmt_info) = false;
+              stop_bb_analysis = true;
+              continue;
+            }
+
           return false;
         }

@@ -2769,6 +2815,7 @@ vect_analyze_data_refs (loop_vec_info lo
             {
               /* Mark the statement as not vectorizable.  */
               STMT_VINFO_VECTORIZABLE (stmt_info) = false;
+              stop_bb_analysis = true;
               continue;
             }
           else

[Bug tree-optimization/50730] SLP vectorization confused by unrelated DRs

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50730

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2011-10-16 12:23:43 UTC ---
First blush, looks like something could be abstracted as a function or a
macro?!?

[Bug tree-optimization/50730] SLP vectorization confused by unrelated DRs

[irar at il dot ibm.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50730

--- Comment #3 from Ira Rosen <irar at il dot ibm.com> 2011-10-22 12:09:30 UTC ---
(In reply to comment #2)
> First blush, looks like something could be abstracted as a function or a
> macro?!?

Hmm, I don't know. There is a 'continue' there...

[Bug tree-optimization/50730] SLP vectorization confused by unrelated DRs

[irar at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50730

--- Comment #4 from irar at gcc dot gnu.org 2011-10-24 09:16:57 UTC ---
Author: irar
Date: Mon Oct 24 09:16:53 2011
New Revision: 180367

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=180367
Log:

        PR tree-optimization/50730
        * tree-vect-data-refs.c (vect_analyze_data_refs): Stop basic
        block analysis if encountered unsupported data-ref.


Added:
    trunk/gcc/testsuite/gcc.dg/vect/no-tree-sra-bb-slp-pr50730.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/vect/vect.exp
    trunk/gcc/tree-vect-data-refs.c

[Bug tree-optimization/50730] SLP vectorization confused by unrelated DRs

[irar at il dot ibm.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50730

Ira Rosen <irar at il dot ibm.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED

--- Comment #5 from Ira Rosen <irar at il dot ibm.com> 2011-11-03 08:49:29 UTC ---
Fixed.

[Bug tree-optimization/50730] SLP vectorization confused by unrelated DRs

[irar at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50730

--- Comment #6 from irar at gcc dot gnu.org 2011-11-04 12:55:11 UTC ---
Author: irar
Date: Fri Nov  4 12:55:06 2011
New Revision: 180945

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=180945
Log:

        Unrevert:
        2011-10-24  Ira Rosen  <ira.rosen@linaro.org>

        PR tree-optimization/50730
        * tree-vect-data-refs.c (vect_analyze_data_refs): Stop basic
        block analysis if encountered unsupported data-ref.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-vect-data-refs.c