re PR tree-optimization/92581 (condition chains vectorized wrongly)

2019-11-19  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/92581
	* tree-vect-loop.c (vect_create_epilog_for_reduction): For
	condition reduction chains gather all conditions involved
	for computing the index reduction vector.

	* gcc.dg/vect/vect-cond-reduc-5.c: New testcase.

From-SVN: r278445

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 81cab100956fd7fefad5ab7418debe9d5ebcce8a..99d6a51d51bf7a5bd990d8d95950142b8a80181c 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2019-11-19  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/92581
+       * tree-vect-loop.c (vect_create_epilog_for_reduction): For
+       condition reduction chains gather all conditions involved
+       for computing the index reduction vector.
+
 2019-11-19  Dennis Zhang  <dennis.zhang@arm.com>
 
        * config/aarch64/aarch64-builtins.c (enum aarch64_builtins): Add

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6cd444c6afa3a75c2e953c57e8ae32cc62d9dc40..2acd0bde8f889dce26ff590bb70ccebf001871e1 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-11-19  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/92581
+       * gcc.dg/vect/vect-cond-reduc-5.c: New testcase.
+
 2019-11-19  Dennis Zhang  <dennis.zhang@arm.com>
 
        * gcc.target/aarch64/acle/memtag_1.c: New test.

diff --git a/gcc/testsuite/gcc.dg/vect/vect-cond-reduc-5.c b/gcc/testsuite/gcc.dg/vect/vect-cond-reduc-5.c
new file mode 100644 (file)
index 0000000..1220875
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-cond-reduc-5.c
@@ -0,0 +1,36 @@
+#include "tree-vect.h"
+
+#define N 512
+
+int a[N], b[N];
+
+int __attribute__((noipa))
+foo (int aval, int bval)
+{
+  int i, res = 0;
+  for (i=0; i<N; i++)
+  {
+    if (a[i] != 0)
+      res = aval;
+    if (b[i] != 0)
+      res = bval;
+  }
+  return res;
+}
+
+int main()
+{
+  check_vect ();
+  if (foo (1, 2) != 0)
+    abort ();
+  a[3] = 1;
+  b[4] = 1;
+  if (foo (1, 2) != 2)
+    abort ();
+  a[7] = 1;
+  if (foo (1, 2) != 1)
+    abort ();
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "vectorized 1 loops" 1 "vect" { target vect_condition } } } */

diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c
index 0e2b6462b4e3f108a96c432dcaf7b8866076b0bc..e4a87e7afe3a150928dac4cd04aa0f3ee1ab3bf7 100644 (file)
--- a/gcc/tree-vect-loop.c
+++ b/gcc/tree-vect-loop.c
@@ -4552,18 +4552,26 @@ vect_create_epilog_for_reduction (stmt_vec_info stmt_info,
      zeroes.  */
   if (STMT_VINFO_REDUC_TYPE (reduc_info) == COND_REDUCTION)
     {
+      auto_vec<std::pair<tree, bool>, 2> ccompares;
       stmt_vec_info cond_info = STMT_VINFO_REDUC_DEF (reduc_info);
       cond_info = vect_stmt_to_vectorize (cond_info);
-      while (gimple_assign_rhs_code (cond_info->stmt) != COND_EXPR)
+      while (cond_info != reduc_info)
        {
+         if (gimple_assign_rhs_code (cond_info->stmt) == COND_EXPR)
+           {
+             gimple *vec_stmt = STMT_VINFO_VEC_STMT (cond_info)->stmt;
+             gcc_assert (gimple_assign_rhs_code (vec_stmt) == VEC_COND_EXPR);
+             ccompares.safe_push
+               (std::make_pair (unshare_expr (gimple_assign_rhs1 (vec_stmt)),
+                                STMT_VINFO_REDUC_IDX (cond_info) == 2));
+           }
          cond_info
            = loop_vinfo->lookup_def (gimple_op (cond_info->stmt,
                                                 1 + STMT_VINFO_REDUC_IDX
                                                        (cond_info)));
          cond_info = vect_stmt_to_vectorize (cond_info);
        }
-      gimple *vec_stmt = STMT_VINFO_VEC_STMT (cond_info)->stmt;
-      gcc_assert (gimple_assign_rhs_code (vec_stmt) == VEC_COND_EXPR);
+      gcc_assert (ccompares.length () != 0);
 
       tree indx_before_incr, indx_after_incr;
       poly_uint64 nunits_out = TYPE_VECTOR_SUBPARTS (vectype);
@@ -4605,37 +4613,35 @@ vect_create_epilog_for_reduction (stmt_vec_info stmt_info,
       add_phi_arg (as_a <gphi *> (new_phi), vec_zero,
                   loop_preheader_edge (loop), UNKNOWN_LOCATION);
 
-      /* Now take the condition from the loops original cond_expr
-        (VEC_STMT) and produce a new cond_expr (INDEX_COND_EXPR) which for
+      /* Now take the condition from the loops original cond_exprs
+        and produce a new cond_exprs (INDEX_COND_EXPR) which for
         every match uses values from the induction variable
         (INDEX_BEFORE_INCR) otherwise uses values from the phi node
         (NEW_PHI_TREE).
         Finally, we update the phi (NEW_PHI_TREE) to take the value of
         the new cond_expr (INDEX_COND_EXPR).  */
-
-      /* Duplicate the condition from vec_stmt.  */
-      tree ccompare = unshare_expr (gimple_assign_rhs1 (vec_stmt));
-
-      /* Create a conditional, where the condition is taken from vec_stmt
-        (CCOMPARE).  The then and else values mirror the main VEC_COND_EXPR:
-        the reduction phi corresponds to NEW_PHI_TREE and the new values
-        correspond to INDEX_BEFORE_INCR.  */
-      gcc_assert (STMT_VINFO_REDUC_IDX (cond_info) >= 1);
-      tree index_cond_expr;
-      if (STMT_VINFO_REDUC_IDX (cond_info) == 2)
-       index_cond_expr = build3 (VEC_COND_EXPR, cr_index_vector_type,
-                                 ccompare, indx_before_incr, new_phi_tree);
-      else
-       index_cond_expr = build3 (VEC_COND_EXPR, cr_index_vector_type,
-                                 ccompare, new_phi_tree, indx_before_incr);
-      induction_index = make_ssa_name (cr_index_vector_type);
-      gimple *index_condition = gimple_build_assign (induction_index,
-                                                    index_cond_expr);
-      gsi_insert_before (&incr_gsi, index_condition, GSI_SAME_STMT);
-      stmt_vec_info index_vec_info = loop_vinfo->add_stmt (index_condition);
+      gimple_seq stmts = NULL;
+      for (int i = ccompares.length () - 1; i != -1; --i)
+       {
+         tree ccompare = ccompares[i].first;
+         if (ccompares[i].second)
+           new_phi_tree = gimple_build (&stmts, VEC_COND_EXPR,
+                                        cr_index_vector_type,
+                                        ccompare,
+                                        indx_before_incr, new_phi_tree);
+         else
+           new_phi_tree = gimple_build (&stmts, VEC_COND_EXPR,
+                                        cr_index_vector_type,
+                                        ccompare,
+                                        new_phi_tree, indx_before_incr);
+       }
+      gsi_insert_seq_before (&incr_gsi, stmts, GSI_SAME_STMT);
+      stmt_vec_info index_vec_info
+       = loop_vinfo->add_stmt (SSA_NAME_DEF_STMT (new_phi_tree));
       STMT_VINFO_VECTYPE (index_vec_info) = cr_index_vector_type;
 
       /* Update the phi with the vec cond.  */
+      induction_index = new_phi_tree;
       add_phi_arg (as_a <gphi *> (new_phi), induction_index,
                   loop_latch_edge (loop), UNKNOWN_LOCATION);
     }