* Makefile.in (OBJS-common): Add tree-chrec.o.

	(tree-chrec.o): New rule.
	(GTFILES): Add tree-chrec.h.
	* gengtype.c (open_base_files): Add tree-chrec.h.
	* tree-chrec.c: New file.
	* tree-chrec.h: New file.
	* tree.def (SCEV_KNOWN, SCEV_NOT_KNOWN, POLYNOMIAL_CHREC): New nodes.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@83909 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 206 insertions, 0 deletions

diff --git a/gcc/tree-chrec.h b/gcc/tree-chrec.h
new file mode 100644
index 00000000000..8e355f0ac35
--- /dev/null
+++ b/gcc/tree-chrec.h
@@ -0,0 +1,206 @@
+/* Chains of recurrences.
+   Copyright (C) 2003, 2004 Free Software Foundation, Inc.
+   Contributed by Sebastian Pop <s.pop@laposte.net>
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 2, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING.  If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA.  */
+
+#ifndef GCC_TREE_CHREC_H
+#define GCC_TREE_CHREC_H
+
+/* Accessors for the chains of recurrences.  */
+#define CHREC_VAR(NODE)           TREE_OPERAND (NODE, 0)
+#define CHREC_LEFT(NODE)          TREE_OPERAND (NODE, 1)
+#define CHREC_RIGHT(NODE)         TREE_OPERAND (NODE, 2)
+#define CHREC_VARIABLE(NODE)      TREE_INT_CST_LOW (CHREC_VAR (NODE))
+
+
+
+/* The following trees are unique elements.  Thus the comparison of another 
+   element to these elements should be done on the pointer to these trees, 
+   and not on their value.  */
+
+extern tree chrec_not_analyzed_yet;
+extern GTY(()) tree chrec_dont_know;
+extern GTY(()) tree chrec_known;
+
+/* After having added an automatically generated element, please
+   include it in the following function.  */
+
+static inline bool
+automatically_generated_chrec_p (tree chrec)
+{
+  return (chrec == chrec_not_analyzed_yet 
+	  || chrec == chrec_dont_know
+	  || chrec == chrec_known);
+}
+
+/* The tree nodes aka. CHRECs.  */
+
+static inline bool
+tree_is_chrec (tree expr)
+{
+  if (TREE_CODE (expr) == POLYNOMIAL_CHREC
+      || automatically_generated_chrec_p (expr))
+    return true;
+  else
+    return false;
+}
+
+
+
+/* Chrec folding functions.  */
+extern tree chrec_fold_plus (tree, tree, tree);
+extern tree chrec_fold_minus (tree, tree, tree);
+extern tree chrec_fold_multiply (tree, tree, tree);
+extern tree chrec_convert (tree, tree);
+extern tree count_ev_in_wider_type (tree, tree);
+extern tree chrec_type (tree);
+
+/* Operations.  */
+extern tree chrec_apply (unsigned, tree, tree);
+extern tree chrec_replace_initial_condition (tree, tree);
+extern tree update_initial_condition_to_origin (tree);
+extern tree initial_condition (tree);
+extern tree evolution_part_in_loop_num (tree, unsigned);
+extern tree hide_evolution_in_other_loops_than_loop (tree, unsigned);
+extern tree reset_evolution_in_loop (unsigned, tree, tree);
+extern tree chrec_merge (tree, tree);
+
+/* Observers.  */
+extern bool is_multivariate_chrec (tree);
+extern bool chrec_is_positive (tree, bool *);
+extern bool chrec_contains_symbols (tree);
+extern bool chrec_contains_symbols_defined_in_loop (tree, unsigned);
+extern bool chrec_contains_undetermined (tree);
+extern bool tree_contains_chrecs (tree);
+extern bool evolution_function_is_affine_multivariate_p (tree);
+extern bool evolution_function_is_univariate_p (tree);
+
+
+
+/* Build a polynomial chain of recurrence.  */
+
+static inline tree 
+build_polynomial_chrec (unsigned loop_num, 
+			tree left, 
+			tree right)
+{
+  if (left == chrec_dont_know
+      || right == chrec_dont_know)
+    return chrec_dont_know;
+
+  return build (POLYNOMIAL_CHREC, TREE_TYPE (left), 
+		build_int_2 (loop_num, 0), left, right);
+}
+
+
+
+/* Observers.  */
+
+/* Determines whether CHREC is equal to zero.  */
+
+static inline bool 
+chrec_zerop (tree chrec)
+{
+  if (chrec == NULL_TREE)
+    return false;
+  
+  if (TREE_CODE (chrec) == INTEGER_CST)
+    return integer_zerop (chrec);
+  
+  return false;
+}
+
+/* Determines whether the expression CHREC is a constant.  */
+
+static inline bool 
+evolution_function_is_constant_p (tree chrec)
+{
+  if (chrec == NULL_TREE)
+    return false;
+
+  switch (TREE_CODE (chrec))
+    {
+    case INTEGER_CST:
+    case REAL_CST:
+      return true;
+      
+    default:
+      return false;
+    }
+}
+
+/* Determine whether the given tree is an affine evolution function or not.  */
+
+static inline bool 
+evolution_function_is_affine_p (tree chrec)
+{
+  if (chrec == NULL_TREE)
+    return false;
+  
+  switch (TREE_CODE (chrec))
+    {
+    case POLYNOMIAL_CHREC:
+      if (evolution_function_is_constant_p (CHREC_LEFT (chrec))
+	  && evolution_function_is_constant_p (CHREC_RIGHT (chrec)))
+	return true;
+      else
+	return false;
+      
+    default:
+      return false;
+    }
+}
+
+/* Determine whether the given tree is an affine or constant evolution
+   function.  */
+
+static inline bool 
+evolution_function_is_affine_or_constant_p (tree chrec)
+{
+  return evolution_function_is_affine_p (chrec) 
+    || evolution_function_is_constant_p (chrec);
+}
+
+/* Determines whether EXPR does not contains chrec expressions.  */
+
+static inline bool
+tree_does_not_contain_chrecs (tree expr)
+{
+  return !tree_contains_chrecs (expr);
+}
+
+/* Determines whether CHREC is a loop invariant with respect to LOOP_NUM.  
+   Set the result in RES and return true when the property can be computed.  */
+
+static inline bool
+no_evolution_in_loop_p (tree chrec, unsigned loop_num, bool *res)
+{
+  tree scev;
+  
+  if (chrec == chrec_not_analyzed_yet
+      || chrec == chrec_dont_know
+      || chrec_contains_symbols_defined_in_loop (chrec, loop_num))
+    return false;
+
+  scev = hide_evolution_in_other_loops_than_loop (chrec, loop_num);
+  *res = !tree_is_chrec (scev);
+  return true;
+}
+
+#endif  /* GCC_TREE_CHREC_H  */