backport PR61929 fix to 5 branch

[Tom de Vries <Tom_deVries at mentor dot com>]

[was: Re: [PATCH] [graphite] fix pr61929]

On 17/07/15 06:31, Tobias Grosser wrote:
> On 07/17/2015 12:23 AM, Sebastian Pop wrote:
> > This fixes bootstrap of GCC with BOOT_CFLAGS="-g -O2 -fgraphite-identity
> > -floop-nest-optimize -floop-block -floop-interchange -floop-strip-mine".
> > It passes regstrap on amd64-linux.
> >
> > Ok to commit to trunk?
>
> Very nice.
>
> this but  seems to include multiple fixes and refactorings at the same
> time. I personally would prefer to at least separate the functional and
> non-functional changes, such that the actual bug fixed becomes clear.
> If splitting the patch is difficult, can you at least point out in the
> commit message, which of your changes now actually fixed the bootstrap?

Hi,

We've run into this PR on the gcc-5-branch (PR71506).

I've applied the fix ( 
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=225942 ) locally 
on top of gcc-5-branch (which applied cleanly), and bootstrapped and 
reg-tested it on x86_64, no issues found.

OK to backport gcc-5-branch, or should I try to strip it down?

Thanks,
- Tom

[ r225942 patch attached. ]

    [graphite] fix pr61929
    
    This fixes bootstrap of GCC with BOOT_CFLAGS="-g -O2 -fgraphite-identity
    -floop-nest-optimize -floop-block -floop-interchange -floop-strip-mine".  It
    passes regstrap on amd64-linux.  A previous change
    (https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=213816), replaced
    isl_int with isl_val because isl_int would be deprecated. Since isl_val has
    stricter checks, it exposed the bug.  In the test case (isl_set_max_val) would
    return infinity which would remain unchecked.  We now check if the value
    returned is an integer or not, and bail out if it isn't.  The other problem was
    that we were allowing all kinds of data-refs in a scop.  Now we discard a scop
    if it has any date-ref other than (ARRAY_REF, MEM_REF, COMPONENT_REF).
    
    	PR middle-end/61929
    	* graphite-dependences.c (add_pdr_constraints): Renamed
    	pdr->extent to pdr->subscript_sizes.
    	* graphite-interchange.c (build_linearized_memory_access): Add
    	back all gcc_assert's that the "isl_int to isl_val conversion"
    	patch has removed.  Refactored.
    	(pdr_stride_in_loop): Renamed pdr->extent to pdr->subscript_sizes.
    	* graphite-poly.c (new_poly_dr): Same.
    	(free_poly_dr): Same.
    	* graphite-poly.h (struct poly_dr): Same.
    	* graphite-scop-detection.c (stmt_has_simple_data_refs_p): Ignore
    	all data references other than ARRAY_REF, MEM_REF, and COMPONENT_REF.
    	* graphite-scop-detection.h: Fix space.
    	* graphite-sese-to-poly.c (build_pbb_scattering_polyhedrons): Add
    	back all gcc_assert's removed by a previous patch.
    	(wrap): Remove the_isl_ctx global variable that the same patch has
    	added.
    	(build_loop_iteration_domains): Same.
    	(add_param_constraints): Same.
    	(pdr_add_data_dimensions): Same.  Refactored.
    	(build_poly_dr): Renamed extent to subscript_sizes.
    
    testsuite/
    	PR middle-end/61929
    	* gcc.dg/graphite/pr61929.c: New.
    
    git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@225942 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/graphite-dependences.c b/gcc/graphite-dependences.c
index 50fe73e..af18ecb 100644
--- a/gcc/graphite-dependences.c
+++ b/gcc/graphite-dependences.c
@@ -88,13 +88,13 @@ constrain_domain (isl_map *map, isl_set *s)
   return isl_map_intersect_domain (map, s);
 }
 
-/* Constrain pdr->accesses with pdr->extent and pbb->domain.  */
+/* Constrain pdr->accesses with pdr->subscript_sizes and pbb->domain.  */
 
 static isl_map *
 add_pdr_constraints (poly_dr_p pdr, poly_bb_p pbb)
 {
   isl_map *x = isl_map_intersect_range (isl_map_copy (pdr->accesses),
-					isl_set_copy (pdr->extent));
+					isl_set_copy (pdr->subscript_sizes));
   x = constrain_domain (x, isl_set_copy (pbb->domain));
   return x;
 }
diff --git a/gcc/graphite-interchange.c b/gcc/graphite-interchange.c
index aee51a8..03c2c63 100644
--- a/gcc/graphite-interchange.c
+++ b/gcc/graphite-interchange.c
@@ -79,37 +79,40 @@ extern "C" {
 static isl_constraint *
 build_linearized_memory_access (isl_map *map, poly_dr_p pdr)
 {
-  isl_constraint *res;
   isl_local_space *ls = isl_local_space_from_space (isl_map_get_space (map));
-  unsigned offset, nsubs;
-  int i;
-  isl_ctx *ctx;
+  isl_constraint *res = isl_equality_alloc (ls);
+  isl_val *size = isl_val_int_from_ui (isl_map_get_ctx (map), 1);
 
-  isl_val *size, *subsize, *size1;
-
-  res = isl_equality_alloc (ls);
-  ctx = isl_local_space_get_ctx (ls);
-  size = isl_val_int_from_ui (ctx, 1);
-
-  nsubs = isl_set_dim (pdr->extent, isl_dim_set);
+  unsigned nsubs = isl_set_dim (pdr->subscript_sizes, isl_dim_set);
   /* -1 for the already included L dimension.  */
-  offset = isl_map_dim (map, isl_dim_out) - 1 - nsubs;
+  unsigned offset = isl_map_dim (map, isl_dim_out) - 1 - nsubs;
   res = isl_constraint_set_coefficient_si (res, isl_dim_out, offset + nsubs, -1);
-  /* Go through all subscripts from last to first.  First dimension
+  /* Go through all subscripts from last to first.  The dimension "i=0"
      is the alias set, ignore it.  */
-  for (i = nsubs - 1; i >= 1; i--)
+  for (int i = nsubs - 1; i >= 1; i--)
     {
-      isl_space *dc;
-      isl_aff *aff;
-
-      size1 = isl_val_copy (size);
-      res = isl_constraint_set_coefficient_val (res, isl_dim_out, offset + i, size);
-      dc = isl_set_get_space (pdr->extent);
-      aff = isl_aff_zero_on_domain (isl_local_space_from_space (dc));
-      aff = isl_aff_set_coefficient_si (aff, isl_dim_in, i, 1);
-      subsize = isl_set_max_val (pdr->extent, aff);
-      isl_aff_free (aff);
-      size = isl_val_mul (size1, subsize);
+      isl_aff *extract_dim;
+      res = isl_constraint_set_coefficient_val (res, isl_dim_out, offset + i,
+						isl_val_copy (size));
+      isl_space *dc = isl_set_get_space (pdr->subscript_sizes);
+      extract_dim = isl_aff_zero_on_domain (isl_local_space_from_space (dc));
+      extract_dim = isl_aff_set_coefficient_si (extract_dim, isl_dim_in, i, 1);
+      isl_val *max = isl_set_max_val (pdr->subscript_sizes, extract_dim);
+      isl_aff_free (extract_dim);
+
+      /* The result is NULL in case of an error, the optimal value in case there
+	 is one, negative infinity or infinity if the problem is unbounded and
+	 NaN if the problem is empty.  */
+      gcc_assert (max);
+
+      /* When one of the dimensions cannot be computed, we cannot build the size
+	 of the array for any outer dimensions.  */
+      if (!isl_val_is_int (max))
+	{
+	  isl_val_free (max);
+	  break;
+	}
+      size = isl_val_mul (size, max);
     }
 
   isl_val_free (size);
@@ -176,7 +179,7 @@ pdr_stride_in_loop (mpz_t stride, graphite_dim_t depth, poly_dr_p pdr)
 
   /* pdr->accesses:    [P1..nb_param,I1..nb_domain]->[a,S1..nb_subscript]
           ??? [P] not used for PDRs?
-     pdr->extent:      [a,S1..nb_subscript]
+     pdr->subscript_sizes:      [a,S1..nb_subscript]
      pbb->domain:      [P1..nb_param,I1..nb_domain]
      pbb->transformed: [P1..nb_param,I1..nb_domain]->[T1..Tnb_sctr]
           [T] includes local vars (currently unused)
diff --git a/gcc/graphite-poly.c b/gcc/graphite-poly.c
index bcd08d8..2eff5a5a 100644
--- a/gcc/graphite-poly.c
+++ b/gcc/graphite-poly.c
@@ -270,7 +270,7 @@ apply_poly_transforms (scop_p scop)
 void
 new_poly_dr (poly_bb_p pbb, int dr_base_object_set,
 	     enum poly_dr_type type, void *cdr, graphite_dim_t nb_subscripts,
-	     isl_map *acc, isl_set *extent)
+	     isl_map *acc, isl_set *subscript_sizes)
 {
   static int id = 0;
   poly_dr_p pdr = XNEW (struct poly_dr);
@@ -280,7 +280,7 @@ new_poly_dr (poly_bb_p pbb, int dr_base_object_set,
   PDR_NB_REFS (pdr) = 1;
   PDR_PBB (pdr) = pbb;
   pdr->accesses = acc;
-  pdr->extent = extent;
+  pdr->subscript_sizes = subscript_sizes;
   PDR_TYPE (pdr) = type;
   PDR_CDR (pdr) = cdr;
   PDR_NB_SUBSCRIPTS (pdr) = nb_subscripts;
@@ -293,7 +293,7 @@ void
 free_poly_dr (poly_dr_p pdr)
 {
   isl_map_free (pdr->accesses);
-  isl_set_free (pdr->extent);
+  isl_set_free (pdr->subscript_sizes);
   XDELETE (pdr);
 }
 
diff --git a/gcc/graphite-poly.h b/gcc/graphite-poly.h
index 7ffd18e..82e1217 100644
--- a/gcc/graphite-poly.h
+++ b/gcc/graphite-poly.h
@@ -177,7 +177,7 @@ struct poly_dr
 
      In the example, the vector "R C O I L P" is "7 7 3 2 0 1".  */
   isl_map *accesses;
-  isl_set *extent;
+  isl_set *subscript_sizes;
 
   /* Data reference's base object set number, we must assure 2 pdrs are in the
      same base object set before dependency checking.  */
diff --git a/gcc/graphite-scop-detection.c b/gcc/graphite-scop-detection.c
index 4fb4e02..28de4ab 100644
--- a/gcc/graphite-scop-detection.c
+++ b/gcc/graphite-scop-detection.c
@@ -289,7 +289,6 @@ stmt_has_simple_data_refs_p (loop_p outermost_loop ATTRIBUTE_UNUSED,
 			     gimple stmt)
 {
   data_reference_p dr;
-  unsigned i;
   int j;
   bool res = true;
   vec<data_reference_p> drs = vNULL;
@@ -302,18 +301,29 @@ stmt_has_simple_data_refs_p (loop_p outermost_loop ATTRIBUTE_UNUSED,
 					     stmt, &drs);
 
       FOR_EACH_VEC_ELT (drs, j, dr)
-	for (i = 0; i < DR_NUM_DIMENSIONS (dr); i++)
-	  if (!graphite_can_represent_scev (DR_ACCESS_FN (dr, i)))
+	{
+	  int nb_subscripts = DR_NUM_DIMENSIONS (dr);
+	  tree ref = DR_REF (dr);
+
+	  for (int i = nb_subscripts - 1; i >= 0; i--)
 	    {
-	      res = false;
-	      goto done;
+	      if (!graphite_can_represent_scev (DR_ACCESS_FN (dr, i))
+		  || (TREE_CODE (ref) != ARRAY_REF
+		      && TREE_CODE (ref) != MEM_REF
+		      && TREE_CODE (ref) != COMPONENT_REF))
+		{
+		  free_data_refs (drs);
+		  return false;
+		}
+
+	      ref = TREE_OPERAND (ref, 0);
 	    }
+	}
 
       free_data_refs (drs);
       drs.create (0);
     }
 
- done:
   free_data_refs (drs);
   return res;
 }
diff --git a/gcc/graphite-scop-detection.h b/gcc/graphite-scop-detection.h
index 8e794c3..4511796 100644
--- a/gcc/graphite-scop-detection.h
+++ b/gcc/graphite-scop-detection.h
@@ -23,7 +23,7 @@ along with GCC; see the file COPYING3.  If not see
 #define GCC_GRAPHITE_SCOP_DETECTION_H
 
 extern void build_scops (vec<scop_p> *);
-extern void dot_all_scops (vec<scop_p> );
+extern void dot_all_scops (vec<scop_p>);
 extern void dot_scop (scop_p);
 
 #endif /* GCC_GRAPHITE_SCOP_DETECTION_H */
diff --git a/gcc/graphite-sese-to-poly.c b/gcc/graphite-sese-to-poly.c
index aaecab4..1e234fe 100644
--- a/gcc/graphite-sese-to-poly.c
+++ b/gcc/graphite-sese-to-poly.c
@@ -497,6 +497,7 @@ build_pbb_scattering_polyhedrons (isl_aff *static_sched,
 	      (isl_local_space_from_space (isl_map_get_space (pbb->schedule)));
 
 	  val = isl_aff_get_coefficient_val (static_sched, isl_dim_in, i / 2);
+	  gcc_assert (val && isl_val_is_int (val));
 
 	  val = isl_val_neg (val);
 	  c = isl_constraint_set_constant_val (c, val);
@@ -719,14 +720,12 @@ extract_affine_int (tree e, __isl_take isl_space *space)
 
 /* Compute pwaff mod 2^width.  */
 
-extern isl_ctx *the_isl_ctx;
-
 static isl_pw_aff *
 wrap (isl_pw_aff *pwaff, unsigned width)
 {
   isl_val *mod;
 
-  mod = isl_val_int_from_ui(the_isl_ctx, width);
+  mod = isl_val_int_from_ui (isl_pw_aff_get_ctx (pwaff), width);
   mod = isl_val_2exp (mod);
   pwaff = isl_pw_aff_mod_val (pwaff, mod);
 
@@ -1012,7 +1011,7 @@ build_loop_iteration_domains (scop_p scop, struct loop *loop,
 	  (isl_local_space_from_space (isl_space_copy (space)));
       c = isl_constraint_set_coefficient_si (c, isl_dim_set, pos, -1);
       tree_int_to_gmp (nb_iters, g);
-      v = isl_val_int_from_gmp (the_isl_ctx, g);
+      v = isl_val_int_from_gmp (scop->ctx, g);
       c = isl_constraint_set_constant_val (c, v);
       inner = isl_set_add_constraint (inner, c);
     }
@@ -1067,7 +1066,7 @@ build_loop_iteration_domains (scop_p scop, struct loop *loop,
 	  c = isl_inequality_alloc
 	      (isl_local_space_from_space (isl_space_copy (space)));
 	  c = isl_constraint_set_coefficient_si (c, isl_dim_set, pos, -1);
-	  v = isl_val_int_from_gmp (the_isl_ctx, g);
+	  v = isl_val_int_from_gmp (scop->ctx, g);
 	  mpz_clear (g);
 	  c = isl_constraint_set_constant_val (c, v);
 	  inner = isl_set_add_constraint (inner, c);
@@ -1335,7 +1334,7 @@ add_param_constraints (scop_p scop, graphite_dim_t p)
       c = isl_inequality_alloc (isl_local_space_from_space (space));
       mpz_init (g);
       tree_int_to_gmp (lb, g);
-      v = isl_val_int_from_gmp (the_isl_ctx, g);
+      v = isl_val_int_from_gmp (scop->ctx, g);
       v = isl_val_neg (v);
       mpz_clear (g);
       c = isl_constraint_set_constant_val (c, v);
@@ -1355,7 +1354,7 @@ add_param_constraints (scop_p scop, graphite_dim_t p)
 
       mpz_init (g);
       tree_int_to_gmp (ub, g);
-      v = isl_val_int_from_gmp (the_isl_ctx, g);
+      v = isl_val_int_from_gmp (scop->ctx, g);
       mpz_clear (g);
       c = isl_constraint_set_constant_val (c, v);
       c = isl_constraint_set_coefficient_si (c, isl_dim_param, p, -1);
@@ -1491,20 +1490,19 @@ pdr_add_memory_accesses (isl_map *acc, data_reference_p dr, poly_bb_p pbb)
    domain.  */
 
 static isl_set *
-pdr_add_data_dimensions (isl_set *extent, scop_p scop, data_reference_p dr)
+pdr_add_data_dimensions (isl_set *subscript_sizes, scop_p scop,
+			 data_reference_p dr)
 {
   tree ref = DR_REF (dr);
-  int i, nb_subscripts = DR_NUM_DIMENSIONS (dr);
 
-  for (i = nb_subscripts - 1; i >= 0; i--, ref = TREE_OPERAND (ref, 0))
+  int nb_subscripts = DR_NUM_DIMENSIONS (dr);
+  for (int i = nb_subscripts - 1; i >= 0; i--, ref = TREE_OPERAND (ref, 0))
     {
-      tree low, high;
-
       if (TREE_CODE (ref) != ARRAY_REF)
-	break;
+	return subscript_sizes;
 
-      low = array_ref_low_bound (ref);
-      high = array_ref_up_bound (ref);
+      tree low = array_ref_low_bound (ref);
+      tree high = array_ref_up_bound (ref);
 
       /* XXX The PPL code dealt separately with
          subscript - low >= 0 and high - subscript >= 0 in case one of
@@ -1522,10 +1520,10 @@ pdr_add_data_dimensions (isl_set *extent, scop_p scop, data_reference_p dr)
 	  isl_aff *aff;
 	  isl_set *univ, *lbs, *ubs;
 	  isl_pw_aff *index;
-	  isl_space *space;
 	  isl_set *valid;
-	  isl_pw_aff *lb = extract_affine_int (low, isl_set_get_space (extent));
-	  isl_pw_aff *ub = extract_affine_int (high, isl_set_get_space (extent));
+	  isl_space *space = isl_set_get_space (subscript_sizes);
+	  isl_pw_aff *lb = extract_affine_int (low, isl_space_copy (space));
+	  isl_pw_aff *ub = extract_affine_int (high, isl_space_copy (space));
 
 	  /* high >= 0 */
 	  valid = isl_pw_aff_nonneg_set (isl_pw_aff_copy (ub));
@@ -1533,25 +1531,24 @@ pdr_add_data_dimensions (isl_set *extent, scop_p scop, data_reference_p dr)
 				       isl_set_dim (valid, isl_dim_set));
 	  scop->context = isl_set_intersect (scop->context, valid);
 
-	  space = isl_set_get_space (extent);
 	  aff = isl_aff_zero_on_domain (isl_local_space_from_space (space));
 	  aff = isl_aff_add_coefficient_si (aff, isl_dim_in, i + 1, 1);
 	  univ = isl_set_universe (isl_space_domain (isl_aff_get_space (aff)));
 	  index = isl_pw_aff_alloc (univ, aff);
 
-	  id = isl_set_get_tuple_id (extent);
+	  id = isl_set_get_tuple_id (subscript_sizes);
 	  lb = isl_pw_aff_set_tuple_id (lb, isl_dim_in, isl_id_copy (id));
 	  ub = isl_pw_aff_set_tuple_id (ub, isl_dim_in, id);
 
 	  /* low <= sub_i <= high */
 	  lbs = isl_pw_aff_ge_set (isl_pw_aff_copy (index), lb);
 	  ubs = isl_pw_aff_le_set (index, ub);
-	  extent = isl_set_intersect (extent, lbs);
-	  extent = isl_set_intersect (extent, ubs);
+	  subscript_sizes = isl_set_intersect (subscript_sizes, lbs);
+	  subscript_sizes = isl_set_intersect (subscript_sizes, ubs);
 	}
     }
 
-  return extent;
+  return subscript_sizes;
 }
 
 /* Build data accesses for DR in PBB.  */
@@ -1561,7 +1558,7 @@ build_poly_dr (data_reference_p dr, poly_bb_p pbb)
 {
   int dr_base_object_set;
   isl_map *acc;
-  isl_set *extent;
+  isl_set *subscript_sizes;
   scop_p scop = PBB_SCOP (pbb);
 
   {
@@ -1588,9 +1585,10 @@ build_poly_dr (data_reference_p dr, poly_bb_p pbb)
       alias_set_num = *(bap->alias_set);
 
     space = isl_space_set_tuple_id (space, isl_dim_set, id);
-    extent = isl_set_nat_universe (space);
-    extent = isl_set_fix_si (extent, isl_dim_set, 0, alias_set_num);
-    extent = pdr_add_data_dimensions (extent, scop, dr);
+    subscript_sizes = isl_set_nat_universe (space);
+    subscript_sizes = isl_set_fix_si (subscript_sizes, isl_dim_set, 0,
+				      alias_set_num);
+    subscript_sizes = pdr_add_data_dimensions (subscript_sizes, scop, dr);
   }
 
   gcc_assert (dr->aux);
@@ -1598,7 +1596,7 @@ build_poly_dr (data_reference_p dr, poly_bb_p pbb)
 
   new_poly_dr (pbb, dr_base_object_set,
 	       DR_IS_READ (dr) ? PDR_READ : PDR_WRITE,
-	       dr, DR_NUM_DIMENSIONS (dr), acc, extent);
+	       dr, DR_NUM_DIMENSIONS (dr), acc, subscript_sizes);
 }
 
 /* Write to FILE the alias graph of data references in DIMACS format.  */
diff --git a/gcc/testsuite/gcc.dg/graphite/pr61929.c b/gcc/testsuite/gcc.dg/graphite/pr61929.c
new file mode 100644
index 0000000..9999ebf
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/graphite/pr61929.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-loop-linear -floop-strip-mine" } */
+
+typedef struct m {
+  char *A;
+  char *B;
+} mystruct;
+mystruct arr[52];
+
+void main () {}
+void generateICE (void)
+{
+  int i;
+  for (i=0; i<52; i++)
+    {
+      arr[i].A = "";
+      arr[i].B = 0;
+    }
+}