Merge evrp uses of substitute_and_fold_engine into the engine itself.

This patch merges the evrp uses of the substitute and fold engine into
the engine itself, at least the parts that can be re-used by other
engine uses.  It also adds a context parameter to get_value() for
further use.

gcc/
	* gimple-loop-versioning.cc (loop_versioning::name_prop::get_value):
	Add stmt parameter.
	* gimple-ssa-evrp.c (class evrp_folder): New.
	(class evrp_dom_walker): Remove.
	(execute_early_vrp): Use evrp_folder instead of evrp_dom_walker.
	* tree-ssa-ccp.c (ccp_folder::get_value): Add stmt parameter.
	* tree-ssa-copy.c (copy_folder::get_value): Same.
	* tree-ssa-propagate.c (substitute_and_fold_engine::replace_uses_in):
	Pass stmt to get_value.
	(substitute_and_fold_engine::replace_phi_args_in): Same.
	(substitute_and_fold_dom_walker::after_dom_children): Call
	post_fold_bb.
	(substitute_and_fold_dom_walker::foreach_new_stmt_in_bb): New.
	(substitute_and_fold_dom_walker::propagate_into_phi_args): New.
	(substitute_and_fold_dom_walker::before_dom_children): Adjust to
	call virtual functions for folding, pre_folding, and post folding.
	Call get_value with PHI.  Tweak dump.
	* tree-ssa-propagate.h (class substitute_and_fold_engine):
	New argument to get_value.
	New virtual function pre_fold_bb.
	New virtual function post_fold_bb.
	New virtual function pre_fold_stmt.
	New virtual function post_new_stmt.
	New function propagate_into_phi_args.
	* tree-vrp.c (vrp_folder::get_value): Add stmt argument.
	* vr-values.c (vr_values::extract_range_from_stmt): Adjust dump
	output.
	(vr_values::fold_cond): New.
	(vr_values::simplify_cond_using_ranges_1): Call fold_cond.
	* vr-values.h (class vr_values): Add
	simplify_cond_using_ranges_when_edge_is_known.
gcc/testsuite/
	* gcc.dg/tree-ssa/ssa-dse-30.c: Adjust test for folding of
	memmove happening later.

1 files changed, 28 insertions, 1 deletions

diff --git a/gcc/vr-values.c b/gcc/vr-values.c
index 2e3a078..e95df78 100644
--- a/gcc/vr-values.c
+++ b/gcc/vr-values.c
@@ -2799,7 +2799,7 @@ vr_values::extract_range_from_stmt (gimple *stmt, edge *taken_edge_p,
 
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
-      fprintf (dump_file, "\nVisiting statement:\n");
+      fprintf (dump_file, "\nextract_range_from_stmt visiting:\n");
       print_gimple_stmt (dump_file, stmt, 0, dump_flags);
     }
 
@@ -3550,6 +3550,30 @@ range_fits_type_p (const value_range_equiv *vr,
   return true;
 }
 
+/* If COND can be folded entirely as TRUE or FALSE, rewrite the
+   conditional as such, and return TRUE.  */
+
+bool
+vr_values::fold_cond (gcond *cond)
+{
+  /* ?? vrp_folder::fold_predicate_in() is a superset of this.  At
+     some point we should merge all variants of this code.  */
+  edge taken_edge;
+  vrp_visit_cond_stmt (cond, &taken_edge);
+  if (taken_edge)
+    {
+      if (taken_edge->flags & EDGE_TRUE_VALUE)
+       gimple_cond_make_true (cond);
+      else if (taken_edge->flags & EDGE_FALSE_VALUE)
+       gimple_cond_make_false (cond);
+      else
+       gcc_unreachable ();
+      update_stmt (cond);
+      return true;
+    }
+  return false;
+}
+
 /* Simplify a conditional using a relational operator to an equality
    test if the range information indicates only one value can satisfy
    the original conditional.  */
@@ -3561,6 +3585,9 @@ vr_values::simplify_cond_using_ranges_1 (gcond *stmt)
   tree op1 = gimple_cond_rhs (stmt);
   enum tree_code cond_code = gimple_cond_code (stmt);
 
+  if (fold_cond (stmt))
+    return true;
+
   if (cond_code != NE_EXPR
       && cond_code != EQ_EXPR
       && TREE_CODE (op0) == SSA_NAME