tree-ssa-loop-niter.c (number_of_iterations_cond): Split into several functions.

	* tree-ssa-loop-niter.c (number_of_iterations_cond): Split into several
	functions.
	(number_of_iterations_ne, number_of_iterations_lt_to_ne,
	assert_no_overflow_lt, assert_loop_rolls_lt, number_of_iterations_lt,
	number_of_iterations_le): New functions.
	(number_of_iterations_special): Removed.
	(number_of_iterations_exit): Do not use number_of_iterations_special.
	* tree.c (unsigned_type_for): Always return integer type.

	* gcc.dg/tree-ssa/pr19210-1.c: Update outcome.  Add new test loop.
	* gcc.dg/tree-ssa/pr19210-2.c: Ditto.

From-SVN: r109702

gcc/ChangeLog

+2006-01-14  Zdenek Dvorak <dvorakz@suse.cz>
+
+	* tree-ssa-loop-niter.c (number_of_iterations_cond): Split into several
+	functions.
+	(number_of_iterations_ne, number_of_iterations_lt_to_ne,
+	assert_no_overflow_lt, assert_loop_rolls_lt, number_of_iterations_lt,
+	number_of_iterations_le): New functions.
+	(number_of_iterations_special): Removed.
+	(number_of_iterations_exit): Do not use number_of_iterations_special.
+	* tree.c (unsigned_type_for): Always return integer type.
+
 2006-01-14  Steven Bosscher  <stevenb.gcc@gmail.com>
 	Richard Guenther  <rguenther@suse.de>
 

gcc/testsuite/ChangeLog

+2005-01-14  Zdenek Dvorak <dvorakz@suse.cz>
+
+	* gcc.dg/tree-ssa/pr19210-1.c: Update outcome.  Add new test loop.
+	* gcc.dg/tree-ssa/pr19210-2.c: Ditto.
+
 2006-01-14  Steven Bosscher  <stevenb.gcc@gmail.com>
 	Richard Guenther  <rguenther@suse.de>
 

gcc/testsuite/gcc.dg/tree-ssa/pr19210-1.c

@@ -12,9 +12,18 @@ f (unsigned n)
   for(k = 0;k <= n;k += 4) /* { dg-warning "cannot optimize.*overflow" } */
     g();
 
-  for(k = 5;k <= n;k += 5) /* { dg-warning "cannot optimize.*overflow" } */
+  /* We used to get warning for this loop.  However, since then # of iterations
+     analysis improved, and we can now prove that this loop does not verflow.
+     This is because the only case when it would overflow is if n = ~0 (since
+     ~0 is divisible by 5), and this cannot be the case, since when we got
+     here, the previous loop exited, thus there exists k > n.  */
+  for(k = 5;k <= n;k += 5)
     g();
 
+  /* So we need the following loop, instead.  */
+  for(k = 4;k <= n;k += 5) /* { dg-warning "cannot optimize.*overflow" } */
+    g();
+  
   for(k = 15;k >= n;k--) /* { dg-warning "cannot optimize.*infinite" } */
     g();
 }

gcc/testsuite/gcc.dg/tree-ssa/pr19210-2.c

@@ -12,7 +12,15 @@ f (unsigned n)
   for(k = 5;k <= n;k += 4) /* { dg-warning "assuming.*not overflow" } */
     g();
 
-  for(k = 5;k <= n;k += 5) /* { dg-warning "assuming.*not overflow" } */
+  /* We used to get warning for this loop.  However, since then # of iterations
+     analysis improved, and we can now prove that this loop does not verflow.
+     This is because the only case when it would overflow is if n = ~0 (since
+     ~0 is divisible by 5), and this cannot be the case, since when we got
+     here, the previous loop exited, thus there exists k > n.  */
+  for(k = 5;k <= n;k += 5)
+    g();
+
+  for(k = 4;k <= n;k += 5) /* { dg-warning "assuming.*not overflow" } */
     g();
 
   for(k = 15;k >= n;k--) /* { dg-warning "assuming.*not infinite" } */

gcc/tree.c

@@ -6809,6 +6809,8 @@ tree_fold_gcd (tree a, tree b)
 tree
 unsigned_type_for (tree type)
 {
+  if (POINTER_TYPE_P (type))
+    return size_type_node;
   return lang_hooks.types.unsigned_type (type);
 }