Re: [PATCH, PR69110] Don't return NULL access_fns in dr_analyze_indices

[Tom de Vries]

On 23/01/16 18:39, Sebastian Pop wrote:
diff --git a/gcc/tree-data-ref.c b/gcc/tree-data-ref.c
index a40f40d..7ff5db7 100644
--- a/gcc/tree-data-ref.c
+++ b/gcc/tree-data-ref.c
@@ -1023,6 +1023,10 @@ dr_analyze_indices (struct data_reference *dr,
loop_p nest, loop_p loop)
      build_int_cst (reference_alias_ptr_type (ref), 0));
      }
+  /* Ensure that DR_NUM_DIMENSIONS (dr) != 0.  */
+  if (access_fns == vNULL)
+    access_fns.safe_push (integer_zero_node);
+
    DR_BASE_OBJECT (dr) = ref;
    DR_ACCESS_FNS (dr) = access_fns;
  }

This code adds a data reference with an access function 0 for all data
references
that cannot be analyzed by the data reference analysis.  Let's move
this check under
the check for DECL_P (ref) and this fixes the check in graphite:

diff --git a/gcc/tree-data-ref.c b/gcc/tree-data-ref.c
index a40f40d..862589b 100644
--- a/gcc/tree-data-ref.c
+++ b/gcc/tree-data-ref.c
@@ -1018,12 +1018,15 @@ dr_analyze_indices (struct data_reference *dr,
loop_p nest, loop_p loop)
    else if (DECL_P (ref))
      {
        /* Canonicalize DR_BASE_OBJECT to MEM_REF form.  */
        ref = build2 (MEM_REF, TREE_TYPE (ref),
                     build_fold_addr_expr (ref),
                     build_int_cst (reference_alias_ptr_type (ref), 0));
+
+      if (access_fns == vNULL)
+       access_fns.safe_push (integer_zero_node);
      }

    DR_BASE_OBJECT (dr) = ref;
    DR_ACCESS_FNS (dr) = access_fns;
  }

Ok with this change.


Hi Sebastian,

That was my original patch, and Richard commented: 'I think avoiding a 
NULL access_fns is ok but it should be done unconditionally, not only 
for the DECL_P case'. In order words, he asked me to do the exact 
opposite of the change you now propose.

Thanks,
- Tom