Enqueue all SRA links for write flag propagation

2017-09-06  Martin Jambor  <mjambor@suse.cz>

	PR tree-optimization/82078
gcc/
	* tree-sra.c (sort_and_splice_var_accesses): Move call to
	add_access_to_work_queue...
	(build_accesses_from_assign): ...here.
	(propagate_all_subaccesses): Make sure racc is the group
	representative, if there is one.

gcc/testsuite/
	* gcc.dg/tree-ssa/pr82078.c: New test.

From-SVN: r251756

gcc/ChangeLog

+2017-09-06  Martin Jambor  <mjambor@suse.cz>
+
+	PR tree-optimization/82078
+	* tree-sra.c (sort_and_splice_var_accesses): Move call to
+	add_access_to_work_queue...
+	(build_accesses_from_assign): ...here.
+	(propagate_all_subaccesses): Make sure racc is the group
+	representative, if there is one.
+
 2017-09-06  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/82095

gcc/testsuite/ChangeLog

+2017-09-06  Martin Jambor  <mjambor@suse.cz>
+
+	PR tree-optimization/82078
+	* gcc.dg/tree-ssa/pr82078.c: New test.
+
 2017-09-06  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/82095

gcc/testsuite/gcc.dg/tree-ssa/pr82078.c

+/* { dg-do run } */
+/* { dg-options "-O" } */
+
+struct S0 {
+  signed f4;
+  signed f9 : 5;
+} a[6][5], b = {2}
+
+;
+int c, d;
+int fn1() {
+  struct S0 e[5][6];
+  struct S0 f;
+  b = f = e[2][5] = a[5][0];
+  if (d)
+    ;
+  else
+    return f.f9;
+  e[c][45] = a[4][4];
+}
+
+int main() {
+  fn1();
+  if (b.f4 != 0)
+    __builtin_abort ();
+  return 0;
+}

gcc/tree-sra.c

@@ -1359,6 +1359,8 @@ build_accesses_from_assign (gimple *stmt)
       link->lacc = lacc;
       link->racc = racc;
       add_link_to_rhs (racc, link);
+      add_access_to_work_queue (racc);
+
       /* Let's delay marking the areas as written until propagation of accesses
 	 across link, unless the nature of rhs tells us that its data comes
 	 from elsewhere.  */
@@ -2118,7 +2120,6 @@ sort_and_splice_var_accesses (tree var)
       access->grp_total_scalarization = total_scalarization;
       access->grp_partial_lhs = grp_partial_lhs;
       access->grp_unscalarizable_region = unscalarizable_region;
-      add_access_to_work_queue (access);
 
       *prev_acc_ptr = access;
       prev_acc_ptr = &access->next_grp;
@@ -2712,6 +2713,8 @@ propagate_all_subaccesses (void)
       struct access *racc = pop_access_from_work_queue ();
       struct assign_link *link;
 
+      if (racc->group_representative)
+	racc= racc->group_representative;
       gcc_assert (racc->first_link);
 
       for (link = racc->first_link; link; link = link->next)