[PR80803 2/2] Diligent queuing in SRA grp_write prop

2017-06-13  Martin Jambor  <mjambor@suse.cz>

	PR tree-optimization/80803
	PR tree-optimization/81063
	* tree-sra.c (subtree_mark_written_and_enqueue): Move up in the file.
	(propagate_subaccesses_across_link): Enqueue subtree whneve necessary
	instead of relying on the caller.

testsuite/
	gcc.dg/tree-ssa/pr80803.c: New test.
	gcc.dg/tree-ssa/pr81063.c: Likewise.

From-SVN: r249154

5 files changed, 174 insertions, 41 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4dec155..bf2efd5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,13 @@
 2017-06-13  Martin Jambor  <mjambor@suse.cz>
 
+	PR tree-optimization/80803
+	PR tree-optimization/81063
+	* tree-sra.c (subtree_mark_written_and_enqueue): Move up in the file.
+	(propagate_subaccesses_across_link): Enqueue subtree whneve necessary
+	instead of relying on the caller.
+
+2017-06-13  Martin Jambor  <mjambor@suse.cz>
+
 	* tree-sra.c (add_access_to_work_queue): Only enqueue accesses
 	that have a first_link.
 	(sort_and_splice_var_accesses): Do not check first_link before
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 71b89de..d9a9fb2 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2017-06-13  Martin Jambor  <mjambor@suse.cz>
+
+	PR tree-optimization/80803
+	PR tree-optimization/81063
+	gcc.dg/tree-ssa/pr80803.c: New test.
+	gcc.dg/tree-ssa/pr81063.c: Likewise.
+
 2017-06-12  Yury Gribov  <tetra2005@gmail.com>
 
 	* c-c++-common/fold-masked-cmp-3.c: New test.
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr80803.c b/gcc/testsuite/gcc.dg/tree-ssa/pr80803.c
new file mode 100644
index 0000000..66834fb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr80803.c
@@ -0,0 +1,72 @@
+/* { dg-do run } */
+/* { dg-options "-O" } */
+
+struct S0
+{
+  unsigned a : 15;
+  int b;
+  int c;
+};
+
+struct S1
+{
+  struct S0 s0;
+  int e;
+};
+
+struct Z
+{
+  char c;
+  int z;
+} __attribute__((packed));
+
+union U
+{
+  struct S1 s1;
+  struct Z z;
+};
+
+
+int __attribute__((noinline, noclone))
+return_zero (void)
+{
+  return 0;
+}
+
+volatile union U gu;
+struct S0 gs;
+
+int __attribute__((noinline, noclone))
+check_outcome ()
+{
+  if (gs.a != 6
+      || gs.b != 80000)
+    __builtin_abort ();
+}
+
+int
+main (int argc, char *argv[])
+{
+  union U u;
+  struct S1 m,n;
+  struct S0 l;
+
+  if (return_zero ())
+    u.z.z = 20000;
+  else
+    {
+      u.s1.s0.a = 6;
+      u.s1.s0.b = 80000;
+      u.s1.e = 2;
+
+      n = u.s1;
+      m = n;
+      m.s0.c = 0;
+      l = m.s0;
+      gs = l;
+    }
+
+  gu = u;
+  check_outcome ();
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr81063.c b/gcc/testsuite/gcc.dg/tree-ssa/pr81063.c
new file mode 100644
index 0000000..399e2d1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr81063.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-O" } */
+
+struct A
+{
+  int b;
+  int c:2;
+};
+
+struct B
+{
+  int e;
+  struct A f;
+} g = {0, {0, 1}}, j;
+
+struct A *h = &g.f;
+
+int main ()
+{
+  struct A k;
+  struct B l = j, i = l;
+  if (!i.f.b)
+    k = i.f;
+  *h = k;
+  if (g.f.c != 0)
+    __builtin_abort ();
+  return 0;
+}
diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index 05bc3d0..c9865c6 100644
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -2558,9 +2558,28 @@ create_artificial_child_access (struct access *parent, struct access *model,
 }
 
 
-/* Propagate all subaccesses of RACC across an assignment link to LACC. Return
-   true if any new subaccess was created.  Additionally, if RACC is a scalar
-   access but LACC is not, change the type of the latter, if possible.  */
+/* Beginning with ACCESS, traverse its whole access subtree and mark all
+   sub-trees as written to.  If any of them has not been marked so previously
+   and has assignment links leading from it, re-enqueue it.  */
+
+static void
+subtree_mark_written_and_enqueue (struct access *access)
+{
+  if (access->grp_write)
+    return;
+  access->grp_write = true;
+  add_access_to_work_queue (access);
+
+  struct access *child;
+  for (child = access->first_child; child; child = child->next_sibling)
+    subtree_mark_written_and_enqueue (child);
+}
+
+/* Propagate subaccesses and grp_write flags of RACC across an assignment link
+   to LACC.  Enqueue sub-accesses as necessary so that the write flag is
+   propagated transitively.  Return true if anything changed.  Additionally, if
+   RACC is a scalar access but LACC is not, change the type of the latter, if
+   possible.  */
 
 static bool
 propagate_subaccesses_across_link (struct access *lacc, struct access *racc)
@@ -2576,7 +2595,7 @@ propagate_subaccesses_across_link (struct access *lacc, struct access *racc)
       gcc_checking_assert (!comes_initialized_p (racc->base));
       if (racc->grp_write)
 	{
-	  lacc->grp_write = true;
+	  subtree_mark_written_and_enqueue (lacc);
 	  ret = true;
 	}
     }
@@ -2585,13 +2604,21 @@ propagate_subaccesses_across_link (struct access *lacc, struct access *racc)
       || lacc->grp_unscalarizable_region
       || racc->grp_unscalarizable_region)
     {
-      ret |= !lacc->grp_write;
-      lacc->grp_write = true;
+      if (!lacc->grp_write)
+	{
+	  ret = true;
+	  subtree_mark_written_and_enqueue (lacc);
+	}
       return ret;
     }
 
   if (is_gimple_reg_type (racc->type))
     {
+      if (!lacc->grp_write)
+	{
+	  ret = true;
+	  subtree_mark_written_and_enqueue (lacc);
+	}
       if (!lacc->first_child && !racc->first_child)
 	{
 	  tree t = lacc->base;
@@ -2616,21 +2643,15 @@ propagate_subaccesses_across_link (struct access *lacc, struct access *racc)
       struct access *new_acc = NULL;
       HOST_WIDE_INT norm_offset = rchild->offset + norm_delta;
 
-      if (rchild->grp_unscalarizable_region)
-	{
-	  lacc->grp_write = true;
-	  continue;
-	}
-
       if (child_would_conflict_in_lacc (lacc, norm_offset, rchild->size,
 					&new_acc))
 	{
 	  if (new_acc)
 	    {
-	      if (!new_acc->grp_write
-		  && (lacc->grp_write || rchild->grp_write))
+	      if (!new_acc->grp_write && rchild->grp_write)
 		{
-		  new_acc ->grp_write = true;
+		  gcc_assert (!lacc->grp_write);
+		  subtree_mark_written_and_enqueue (new_acc);
 		  ret = true;
 		}
 
@@ -2640,7 +2661,23 @@ propagate_subaccesses_across_link (struct access *lacc, struct access *racc)
 		ret |= propagate_subaccesses_across_link (new_acc, rchild);
 	    }
 	  else
-	    lacc->grp_write = true;
+	    {
+	      if (rchild->grp_write && !lacc->grp_write)
+		{
+		  ret = true;
+		  subtree_mark_written_and_enqueue (lacc);
+		}
+	    }
+	  continue;
+	}
+
+      if (rchild->grp_unscalarizable_region)
+	{
+	  if (rchild->grp_write && !lacc->grp_write)
+	    {
+	      ret = true;
+	      subtree_mark_written_and_enqueue (lacc);
+	    }
 	  continue;
 	}
 
@@ -2648,36 +2685,17 @@ propagate_subaccesses_across_link (struct access *lacc, struct access *racc)
       new_acc = create_artificial_child_access (lacc, rchild, norm_offset,
 						lacc->grp_write
 						|| rchild->grp_write);
-      if (new_acc)
-	{
-	  ret = true;
-	  if (racc->first_child)
-	    propagate_subaccesses_across_link (new_acc, rchild);
-	}
+      gcc_checking_assert (new_acc);
+      if (racc->first_child)
+	propagate_subaccesses_across_link (new_acc, rchild);
+
+      add_access_to_work_queue (lacc);
+      ret = true;
     }
 
   return ret;
 }
 
-/* Beginning with ACCESS, traverse its whole access subtree and mark all
-   sub-trees as written to.  If any of them has not been marked so previously
-   and has assignment links leading from it, re-enqueue it.  */
-
-static void
-subtree_mark_written_and_enqueue (struct access *access)
-{
-  if (access->grp_write)
-    return;
-  access->grp_write = true;
-  add_access_to_work_queue (access);
-
-  struct access *child;
-  for (child = access->first_child; child; child = child->next_sibling)
-    subtree_mark_written_and_enqueue (child);
-}
-
-
-
 /* Propagate all subaccesses across assignment links.  */
 
 static void