[patch] In Graphite, don't compute the new IV type based on the old_iv type

[Sebastian Pop <sebpop at gmail dot com>]

Hi,

The attached patch is one step forward in eliminating the need
to canonicalize the IVs in loops handled by graphite.  The patch
eliminates one use of the loop->single_iv in the computation of
the type of the new induction variable.

I committed this patch to the graphite branch for a full test.
I will commit this to trunk once that passes.

Sebastian Pop
--
AMD / Open Source Compiler Engineering / GNU Tools

From b1030d21297bb4d019dee3ca606880e9e165105f Mon Sep 17 00:00:00 2001
From: Sebastian Pop <sebpop@gmail.com>
Date: Fri, 11 Jun 2010 13:05:37 -0500
Subject: [PATCH] Don't call pbb_to_depth_to_oldiv from compute_type_for_level.

2010-06-11  Sebastian Pop  <sebastian.pop@amd.com>

	* graphite-clast-to-gimple.c (gcc_type_for_interval): Do not pass
	old_type in parameter.
	(gcc_type_for_value): Update call to gcc_type_for_interval.
	(compute_type_for_level_1): Renamed compute_type_for_level.
	Update call to gcc_type_for_interval.
---
 gcc/ChangeLog.graphite         |    8 +++++++
 gcc/graphite-clast-to-gimple.c |   46 +++++++---------------------------------
 2 files changed, 16 insertions(+), 38 deletions(-)

diff --git a/gcc/ChangeLog.graphite b/gcc/ChangeLog.graphite
index 18adc7a..6df816b 100644
--- a/gcc/ChangeLog.graphite
+++ b/gcc/ChangeLog.graphite
@@ -1,3 +1,11 @@
+2010-06-11  Sebastian Pop  <sebastian.pop@amd.com>
+
+	* graphite-clast-to-gimple.c (gcc_type_for_interval): Do not pass
+	old_type in parameter.
+	(gcc_type_for_value): Update call to gcc_type_for_interval.
+	(compute_type_for_level_1): Renamed compute_type_for_level.
+	Update call to gcc_type_for_interval.
+
 2010-06-09  Sebastian Pop  <sebastian.pop@amd.com>
 
 	* tree-scalar-evolution.c (instantiate_scev_name): Do not fail
diff --git a/gcc/graphite-clast-to-gimple.c b/gcc/graphite-clast-to-gimple.c
index ee00ed3..a363f5d 100644
--- a/gcc/graphite-clast-to-gimple.c
+++ b/gcc/graphite-clast-to-gimple.c
@@ -469,11 +469,10 @@ precision_for_interval (mpz_t low, mpz_t up)
   return precision;
 }
 
-/* Return a type that could represent the integer value VAL, or
-   otherwise return NULL_TREE.  */
+/* Return a type that could represent the integer value VAL.  */
 
 static tree
-gcc_type_for_interval (mpz_t low, mpz_t up, tree old_type)
+gcc_type_for_interval (mpz_t low, mpz_t up)
 {
   bool unsigned_p = true;
   int precision, prec_up, prec_int;
@@ -482,14 +481,12 @@ gcc_type_for_interval (mpz_t low, mpz_t up, tree old_type)
 
   gcc_assert (value_le (low, up));
 
-  /* Preserve the signedness of the old IV.  */
-  if ((old_type && !TYPE_UNSIGNED (old_type))
-      || value_neg_p (low))
+  if (value_neg_p (low))
     unsigned_p = false;
 
   prec_up = precision_for_value (up);
   prec_int = precision_for_interval (low, up);
-  precision = prec_up > prec_int ? prec_up : prec_int;
+  precision = MAX (prec_up, prec_int);
 
   if (precision > BITS_PER_WORD)
     {
@@ -516,7 +513,7 @@ gcc_type_for_interval (mpz_t low, mpz_t up, tree old_type)
 static tree
 gcc_type_for_value (mpz_t val)
 {
-  return gcc_type_for_interval (val, val, NULL_TREE);
+  return gcc_type_for_interval (val, val);
 }
 
 /* Return the type for the clast_term T used in STMT.  */
@@ -726,11 +723,10 @@ compute_bounds_for_level (poly_bb_p pbb, int level, mpz_t low, mpz_t up)
 }
 
 /* Compute the type for the induction variable at LEVEL for the
-   statement PBB, based on the transformed schedule of PBB.  OLD_TYPE
-   is the type of the old induction variable for that loop.  */
+   statement PBB, based on the transformed schedule of PBB.  */
 
 static tree
-compute_type_for_level_1 (poly_bb_p pbb, int level, tree old_type)
+compute_type_for_level (poly_bb_p pbb, int level)
 {
   mpz_t low, up;
   tree type;
@@ -739,39 +735,13 @@ compute_type_for_level_1 (poly_bb_p pbb, int level, tree old_type)
   value_init (up);
 
   compute_bounds_for_level (pbb, level, low, up);
-  type = gcc_type_for_interval (low, up, old_type);
+  type = gcc_type_for_interval (low, up);
 
   value_clear (low);
   value_clear (up);
   return type;
 }
 
-/* Compute the type for the induction variable at LEVEL for the
-   statement PBB, based on the transformed schedule of PBB.  */
-
-static tree
-compute_type_for_level (poly_bb_p pbb, int level)
-{
-  tree oldiv = pbb_to_depth_to_oldiv (pbb, level);
-  tree type = TREE_TYPE (oldiv);
-
-  if (type && POINTER_TYPE_P (type))
-    {
-#ifdef ENABLE_CHECKING
-      tree ctype = compute_type_for_level_1 (pbb, level, type);
-
-      /* In the case of a pointer type, check that after the loop
-	 transform, the lower and the upper bounds of the type fit the
-	 oldiv pointer type.  */
-      gcc_assert (TYPE_PRECISION (type) >= TYPE_PRECISION (ctype)
-		  && integer_zerop (lower_bound_in_type (ctype, ctype)));
-#endif
-      return type;
-    }
-
-  return compute_type_for_level_1 (pbb, level, type);
-}
-
 /* Walks a CLAST and returns the first statement in the body of a
    loop.  */
 
-- 
1.7.0.4