correctly handle non affine data references

2015-10-01  Sebastian Pop  <s.pop@samsung.com>
            Aditya Kumar  <aditya.k7@samsung.com>
        PR tree-optimization/66980
        * graphite-scop-detection.c (stmt_has_simple_data_refs_p): Return false
        when data reference analysis has failed.

Co-Authored-By: Aditya Kumar <aditya.k7@samsung.com>

From-SVN: r228357

gcc/ChangeLog

 2015-10-01  Sebastian Pop  <s.pop@samsung.com>
 	    Aditya Kumar  <aditya.k7@samsung.com>
 
+	PR tree-optimization/66980
+	* graphite-scop-detection.c (stmt_has_simple_data_refs_p): Return false
+	when data reference analysis has failed.
+
+2015-10-01  Sebastian Pop  <s.pop@samsung.com>
+	    Aditya Kumar  <aditya.k7@samsung.com>
+
 	PR tree-optimization/67754
 	* graphite-scop-detection.c (stmt_has_simple_data_refs_p): Call
 	scev analysis on the same loop nest as analyze_drs_in_stmts.

gcc/graphite-scop-detection.c

@@ -274,6 +274,13 @@ stmt_has_simple_data_refs_p (sese_l scop, gimple *stmt)
   FOR_EACH_VEC_ELT (drs, j, dr)
     {
       int nb_subscripts = DR_NUM_DIMENSIONS (dr);
+
+      if (nb_subscripts < 1)
+	{
+	  free_data_refs (drs);
+	  return false;
+	}
+
       tree ref = DR_REF (dr);
 
       for (int i = nb_subscripts - 1; i >= 0; i--)

gcc/testsuite/gcc.dg/graphite/scop-pr66980.c

+void foo(unsigned char *in, unsigned char *out, int w, int h)
+{
+  unsigned int i, j;
+  for (i = 0; i < 3*w*h; i++)
+    for (j = 0; j < 3*w*h; j++)
+      out[i * w + j] = in[(i * w + j)*3] + in[(i * w + j)*3 + 1] + in[(i * w + j)*3 + 2];
+}
+
+/* Requires delinearization to be able to represent "i*w".  */
+/* { dg-final { scan-tree-dump-times "number of SCoPs: 1" 1 "graphite" { xfail *-*-* } } } */