* tree-cfg.c (tree_can_merge_blocks_p): Allow phi nodes in the

	merged block.
	(replace_uses_by): New function.
	(tree_merge_blocks): Eliminate the phi nodes in the merged block.
	* tree-flow.h (fold_stmt_inplace): Declare.
	* tree-ssa-ccp.c (fold_stmt_inplace): New function.
	* tree-ssa-dom.c (tree_ssa_dominator_optimize): Update dominance
	info after cfg cleanup.


git-svn-id: https://gcc.gnu.org/svn/gcc/trunk@99850 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 26 insertions, 0 deletions

diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c
index 85753bdd764..45472f402ab 100644
--- a/gcc/tree-ssa-ccp.c
+++ b/gcc/tree-ssa-ccp.c
@@ -2308,6 +2308,32 @@ fold_stmt (tree *stmt_p)
   return changed;
 }
 
+/* Perform the minimal folding on statement STMT.  Only operations like
+   *&x created by constant propagation are handled.  The statement cannot
+   be replaced with a new one.  */
+
+bool
+fold_stmt_inplace (tree stmt)
+{
+  tree old_stmt = stmt, rhs, new_rhs;
+  bool changed = false;
+
+  walk_tree (&stmt, fold_stmt_r, &changed, NULL);
+  gcc_assert (stmt == old_stmt);
+
+  rhs = get_rhs (stmt);
+  if (!rhs || rhs == stmt)
+    return changed;
+
+  new_rhs = fold (rhs);
+  if (new_rhs == rhs)
+    return changed;
+
+  changed |= set_rhs (&stmt, new_rhs);
+  gcc_assert (stmt == old_stmt);
+
+  return changed;
+}
 
 /* Convert EXPR into a GIMPLE value suitable for substitution on the
    RHS of an assignment.  Insert the necessary statements before