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, 8 insertions, 15 deletions

diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index ce63cc1..5c26592 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -635,15 +635,11 @@ tree
 ao_ref_base (ao_ref *ref)
 {
   bool reverse;
-  HOST_WIDE_INT offset, size, max_size;
 
   if (ref->base)
     return ref->base;
-  ref->base = get_ref_base_and_extent (ref->ref, &offset, &size,
-				       &max_size, &reverse);
-  ref->offset = offset;
-  ref->size = size;
-  ref->max_size = max_size;
+  ref->base = get_ref_base_and_extent (ref->ref, &ref->offset, &ref->size,
+				       &ref->max_size, &reverse);
   return ref->base;
 }
 
@@ -823,7 +819,7 @@ aliasing_component_refs_p (tree ref1,
     return true;
   else if (same_p == 1)
     {
-      HOST_WIDE_INT offadj, sztmp, msztmp;
+      poly_int64 offadj, sztmp, msztmp;
       bool reverse;
       get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp, &reverse);
       offset2 -= offadj;
@@ -842,7 +838,7 @@ aliasing_component_refs_p (tree ref1,
     return true;
   else if (same_p == 1)
     {
-      HOST_WIDE_INT offadj, sztmp, msztmp;
+      poly_int64 offadj, sztmp, msztmp;
       bool reverse;
       get_ref_base_and_extent (*refp, &offadj, &sztmp, &msztmp, &reverse);
       offset1 -= offadj;
@@ -2448,15 +2444,12 @@ stmt_kills_ref_p (gimple *stmt, ao_ref *ref)
 	 the access properly.  */
       if (!ref->max_size_known_p ())
 	return false;
-      HOST_WIDE_INT size, max_size, const_offset;
-      poly_int64 ref_offset = ref->offset;
+      poly_int64 size, offset, max_size, ref_offset = ref->offset;
       bool reverse;
-      tree base
-	= get_ref_base_and_extent (lhs, &const_offset, &size, &max_size,
-				   &reverse);
+      tree base = get_ref_base_and_extent (lhs, &offset, &size, &max_size,
+					   &reverse);
       /* We can get MEM[symbol: sZ, index: D.8862_1] here,
 	 so base == ref->base does not always hold.  */
-      poly_int64 offset = const_offset;
       if (base != ref->base)
 	{
 	  /* Try using points-to info.  */
@@ -2488,7 +2481,7 @@ stmt_kills_ref_p (gimple *stmt, ao_ref *ref)
 	}
       /* For a must-alias check we need to be able to constrain
 	 the access properly.  */
-      if (size == max_size
+      if (known_eq (size, max_size)
 	  && known_subrange_p (ref_offset, ref->max_size, offset, size))
 	return true;
     }