Fix PR47653: do not handle loops using wrapping semantics in graphite

2011-07-26  Sebastian Pop  <sebastian.pop@amd.com>

	PR middle-end/47653
	* graphite-scop-detection.c (graphite_can_represent_loop): Discard
	loops using wrapping semantics.

	* gcc.dg/graphite/run-id-pr47653.c: New.
	* gcc.dg/graphite/interchange-3.c: Do not use unsigned types for
	induction variables.
	* gcc.dg/graphite/scop-16.c: Same.
	* gcc.dg/graphite/scop-17.c: Same.
	* gcc.dg/graphite/scop-21.c: Same.

From-SVN: r176802

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2011-07-26  Sebastian Pop  <sebastian.pop@amd.com>
+
+	PR middle-end/47653
+	* graphite-scop-detection.c (graphite_can_represent_loop): Discard
+	loops using wrapping semantics.
+
 2011-07-26  Sebastian Pop  <sebastian.pop@amd.com>
 
 	PR middle-end/48805

gcc/graphite-scop-detection.c

@@ -378,17 +378,17 @@ harmful_stmt_in_bb (basic_block scop_entry, loop_p outer_loop, basic_block bb)
 static bool
 graphite_can_represent_loop (basic_block scop_entry, loop_p loop)
 {
-  tree niter = number_of_latch_executions (loop);
+  tree niter;
+  struct tree_niter_desc niter_desc;
 
-  /* Number of iterations unknown.  */
-  if (chrec_contains_undetermined (niter))
-    return false;
+  /* FIXME: For the moment, graphite cannot be used on loops that
+     iterate using induction variables that wrap.  */
 
-  /* Number of iterations not affine.  */
-  if (!graphite_can_represent_expr (scop_entry, loop, niter))
-    return false;
-
-  return true;
+  return number_of_iterations_exit (loop, single_exit (loop), &niter_desc, false)
+    && niter_desc.control.no_overflow
+    && (niter = number_of_latch_executions (loop))
+    && !chrec_contains_undetermined (niter)
+    && graphite_can_represent_expr (scop_entry, loop, niter);
 }
 
 /* Store information needed by scopdet_* functions.  */

gcc/testsuite/ChangeLog

@@ -1,3 +1,13 @@
+2011-07-26  Sebastian Pop  <sebastian.pop@amd.com>
+
+	PR middle-end/47653
+	* gcc.dg/graphite/run-id-pr47653.c: New.
+	* gcc.dg/graphite/interchange-3.c: Do not use unsigned types for
+	induction variables.
+	* gcc.dg/graphite/scop-16.c: Same.
+	* gcc.dg/graphite/scop-17.c: Same.
+	* gcc.dg/graphite/scop-21.c: Same.
+
 2011-07-26  Sebastian Pop  <sebastian.pop@amd.com>
 
 	PR middle-end/48805

gcc/testsuite/gcc.dg/graphite/interchange-3.c

@@ -12,7 +12,7 @@ double u[1782225];
 static void __attribute__((noinline))
 foo (int N, int *res)
 {
-  unsigned int i, j;
+  int i, j;
   double sum = 0;
   for (i = 0; i < N; i++)
     {

gcc/testsuite/gcc.dg/graphite/run-id-pr47653.c

@@ -0,0 +1,17 @@
+/* { dg-options "-O -fstack-check=generic -ftree-pre -fgraphite-identity" } */
+
+int main ()
+{
+  int i, j;
+  int x[8][8];
+  for (i = 0; i < 8; i++)
+    for (j = i; j < 8; j++)
+      x[i][j] = 4;
+
+  for (i = 0; i < 8; i++)
+    for (j = i; j < 8; j++)
+      if (x[i][j] != 4)
+	__builtin_abort ();
+
+  return 0;
+}

gcc/testsuite/gcc.dg/graphite/scop-16.c

@@ -6,7 +6,7 @@ int test ()
 {
   int a[N][N];
   int b[N][N];
-  unsigned i, j;
+  int i, j;
 
   for (i = 0; i < N; i++) 
     for (j = 0; j < N; j++)

gcc/testsuite/gcc.dg/graphite/scop-17.c

@@ -5,7 +5,7 @@ void foo (int);
 int test ()
 {
   int a[N][N];
-  unsigned i, j;
+  int i, j;
 
   for (i = 0; i < N; i++) 
     for (j = 0; j < N; j++)

gcc/testsuite/gcc.dg/graphite/scop-21.c

@@ -3,7 +3,7 @@ void foo (int);
 int test ()
 {
   int a[N+6];
-  unsigned i;
+  int i;
 
   for (i = 0; i < N; i++)
     {

libgomp/testsuite/libgomp.graphite/force-parallel-1.c

@@ -23,7 +23,7 @@ int main(void)
 }
 
 /* Check that parallel code generation part make the right answer.  */
-/* { dg-final { scan-tree-dump-times "1 loops carried no dependency" 2 "graphite" } } */
+/* { dg-final { scan-tree-dump-times "1 loops carried no dependency" 2 "graphite" { xfail *-*-* } } } */
 /* { dg-final { cleanup-tree-dump "graphite" } } */
 /* { dg-final { scan-tree-dump-times "loopfn" 5 "optimized" } } */
 /* { dg-final { cleanup-tree-dump "parloops" } } */