* gcc.c-torture/execute/pr58387.c: New test.

	* tree-ssa-dom.c (cprop_into_successor_phis): Also propagate
	edge implied equivalences into successor phis.
	* tree-ssa-threadupdate.c (phi_args_equal_on_edges): Moved into
	here from tree-ssa-threadedge.c.
	(mark_threaded_blocks): When threading through a joiner, if both
	successors of the joiner's clone reach the same block, verify the
	PHI arguments are equal.  If not, cancel the jump threading request.
	* tree-ssa-threadedge.c (phi_args_equal_on_edges): Moved into
	tree-ssa-threadupdate.c
	(thread_across_edge): Don't check PHI argument equality when
	threading through joiner block here.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@202660 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 25 insertions, 1 deletions

diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c
index e02a56662b9..4a2b48bd93d 100644
--- a/gcc/tree-ssa-dom.c
+++ b/gcc/tree-ssa-dom.c
@@ -1235,7 +1235,7 @@ record_equivalences_from_incoming_edge (basic_block bb)
 
 		  /* If the conversion widens the original value and
 		     the constant is in the range of the type of OLD_RHS,
-		     then convert the constant and record the equivalence. 
+		     then convert the constant and record the equivalence.
 
 		     Note that int_fits_type_p does not check the precision
 		     if the upper and lower bounds are OK.  */
@@ -1642,6 +1642,28 @@ cprop_into_successor_phis (basic_block bb)
       if (gsi_end_p (gsi))
 	continue;
 
+      /* We may have an equivalence associated with this edge.  While
+	 we can not propagate it into non-dominated blocks, we can
+	 propagate them into PHIs in non-dominated blocks.  */
+
+      /* Push the unwind marker so we can reset the const and copies
+	 table back to its original state after processing this edge.  */
+      const_and_copies_stack.safe_push (NULL_TREE);
+
+      /* Extract and record any simple NAME = VALUE equivalences.
+
+	 Don't bother with [01] = COND equivalences, they're not useful
+	 here.  */
+      struct edge_info *edge_info = (struct edge_info *) e->aux;
+      if (edge_info)
+	{
+	  tree lhs = edge_info->lhs;
+	  tree rhs = edge_info->rhs;
+
+	  if (lhs && TREE_CODE (lhs) == SSA_NAME)
+	    record_const_or_copy (lhs, rhs);
+	}
+
       indx = e->dest_idx;
       for ( ; !gsi_end_p (gsi); gsi_next (&gsi))
 	{
@@ -1667,6 +1689,8 @@ cprop_into_successor_phis (basic_block bb)
 	      && may_propagate_copy (orig_val, new_val))
 	    propagate_value (orig_p, new_val);
 	}
+
+      restore_vars_to_original_value ();
     }
 }