poly_int: get_ref_base_and_extent

This patch changes the types of the bit offsets and sizes returned
by get_ref_base_and_extent to poly_int64.

There are some callers that can't sensibly operate on polynomial
offsets or handle cases where the offset and size aren't known
exactly.  This includes the IPA devirtualisation code (since
there's no defined way of having vtables at variable offsets)
and some parts of the DWARF code.  The patch therefore adds
a helper function get_ref_base_and_extent_hwi that either returns
exact HOST_WIDE_INT bit positions and sizes or returns a null
base to indicate failure.

2017-12-20  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* tree-dfa.h (get_ref_base_and_extent): Return the base, size and
	max_size as poly_int64_pods rather than HOST_WIDE_INTs.
	(get_ref_base_and_extent_hwi): Declare.
	* tree-dfa.c (get_ref_base_and_extent): Return the base, size and
	max_size as poly_int64_pods rather than HOST_WIDE_INTs.
	(get_ref_base_and_extent_hwi): New function.
	* cfgexpand.c (expand_debug_expr): Update call to
	get_ref_base_and_extent.
	* dwarf2out.c (add_var_loc_to_decl): Likewise.
	* gimple-fold.c (get_base_constructor): Return the offset as a
	poly_int64_pod rather than a HOST_WIDE_INT.
	(fold_const_aggregate_ref_1): Track polynomial sizes and offsets.
	* ipa-polymorphic-call.c
	(ipa_polymorphic_call_context::set_by_invariant)
	(extr_type_from_vtbl_ptr_store): Track polynomial offsets.
	(ipa_polymorphic_call_context::ipa_polymorphic_call_context)
	(check_stmt_for_type_change): Use get_ref_base_and_extent_hwi
	rather than get_ref_base_and_extent.
	(ipa_polymorphic_call_context::get_dynamic_type): Likewise.
	* ipa-prop.c (ipa_load_from_parm_agg, compute_complex_assign_jump_func)
	(get_ancestor_addr_info, determine_locally_known_aggregate_parts):
	Likewise.
	* ipa-param-manipulation.c (ipa_get_adjustment_candidate): Update
	call to get_ref_base_and_extent.
	* tree-sra.c (create_access, get_access_for_expr): Likewise.
	* tree-ssa-alias.c (ao_ref_base, aliasing_component_refs_p)
	(stmt_kills_ref_p): Likewise.
	* tree-ssa-dce.c (mark_aliased_reaching_defs_necessary_1): Likewise.
	* tree-ssa-scopedtables.c (avail_expr_hash, equal_mem_array_ref_p):
	Likewise.
	* tree-ssa-sccvn.c (vn_reference_lookup_3): Likewise.
	Use get_ref_base_and_extent_hwi rather than get_ref_base_and_extent
	when calling native_encode_expr.
	* tree-ssa-structalias.c (get_constraint_for_component_ref): Update
	call to get_ref_base_and_extent.
	(do_structure_copy): Use get_ref_base_and_extent_hwi rather than
	get_ref_base_and_extent.
	* var-tracking.c (track_expr_p): Likewise.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r255886

1 files changed, 11 insertions, 11 deletions

diff --git a/gcc/tree-ssa-scopedtables.c b/gcc/tree-ssa-scopedtables.c
index 27e0c68..5177511 100644
--- a/gcc/tree-ssa-scopedtables.c
+++ b/gcc/tree-ssa-scopedtables.c
@@ -480,13 +480,13 @@ avail_expr_hash (class expr_hash_elt *p)
 	     Dealing with both MEM_REF and ARRAY_REF allows us not to care
 	     about equivalence with other statements not considered here.  */
 	  bool reverse;
-	  HOST_WIDE_INT offset, size, max_size;
+	  poly_int64 offset, size, max_size;
 	  tree base = get_ref_base_and_extent (t, &offset, &size, &max_size,
 					       &reverse);
 	  /* Strictly, we could try to normalize variable-sized accesses too,
 	    but here we just deal with the common case.  */
-	  if (size != -1
-	      && size == max_size)
+	  if (known_size_p (max_size)
+	      && known_eq (size, max_size))
 	    {
 	      enum tree_code code = MEM_REF;
 	      hstate.add_object (code);
@@ -520,26 +520,26 @@ equal_mem_array_ref_p (tree t0, tree t1)
   if (!types_compatible_p (TREE_TYPE (t0), TREE_TYPE (t1)))
     return false;
   bool rev0;
-  HOST_WIDE_INT off0, sz0, max0;
+  poly_int64 off0, sz0, max0;
   tree base0 = get_ref_base_and_extent (t0, &off0, &sz0, &max0, &rev0);
-  if (sz0 == -1
-      || sz0 != max0)
+  if (!known_size_p (max0)
+      || maybe_ne (sz0, max0))
     return false;
 
   bool rev1;
-  HOST_WIDE_INT off1, sz1, max1;
+  poly_int64 off1, sz1, max1;
   tree base1 = get_ref_base_and_extent (t1, &off1, &sz1, &max1, &rev1);
-  if (sz1 == -1
-      || sz1 != max1)
+  if (!known_size_p (max1)
+      || maybe_ne (sz1, max1))
     return false;
 
   if (rev0 != rev1)
     return false;
 
   /* Types were compatible, so this is a sanity check.  */
-  gcc_assert (sz0 == sz1);
+  gcc_assert (known_eq (sz0, sz1));
 
-  return (off0 == off1) && operand_equal_p (base0, base1, 0);
+  return known_eq (off0, off1) && operand_equal_p (base0, base1, 0);
 }
 
 /* Compare two hashable_expr structures for equivalence.  They are