poly_int: MEM_OFFSET and MEM_SIZE

This patch changes the MEM_OFFSET and MEM_SIZE memory attributes
from HOST_WIDE_INT to poly_int64.  Most of it is mechanical,
but there is one nonbovious change in widen_memory_access.
Previously the main while loop broke with:

      /* Similarly for the decl.  */
      else if (DECL_P (attrs.expr)
               && DECL_SIZE_UNIT (attrs.expr)
               && TREE_CODE (DECL_SIZE_UNIT (attrs.expr)) == INTEGER_CST
               && compare_tree_int (DECL_SIZE_UNIT (attrs.expr), size) >= 0
               && (! attrs.offset_known_p || attrs.offset >= 0))
        break;

but it seemed wrong to optimistically assume the best case
when the offset isn't known (and thus might be negative).
As it happens, the "! attrs.offset_known_p" condition was
always false, because we'd already nullified attrs.expr in
that case:

  /* If we don't know what offset we were at within the expression, then
     we can't know if we've overstepped the bounds.  */
  if (! attrs.offset_known_p)
    attrs.expr = NULL_TREE;

The patch therefore drops "! attrs.offset_known_p ||" when
converting the offset check to the may/must interface.

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

gcc/
	* rtl.h (mem_attrs): Add a default constructor.  Change size and
	offset from HOST_WIDE_INT to poly_int64.
	* emit-rtl.h (set_mem_offset, set_mem_size, adjust_address_1)
	(adjust_automodify_address_1, set_mem_attributes_minus_bitpos)
	(widen_memory_access): Take the sizes and offsets as poly_int64s
	rather than HOST_WIDE_INTs.
	* alias.c (ao_ref_from_mem): Handle the new form of MEM_OFFSET.
	(offset_overlap_p): Take poly_int64s rather than HOST_WIDE_INTs
	and ints.
	(adjust_offset_for_component_ref): Change the offset from a
	HOST_WIDE_INT to a poly_int64.
	(nonoverlapping_memrefs_p): Track polynomial offsets and sizes.
	* cfgcleanup.c (merge_memattrs): Update after mem_attrs changes.
	* dce.c (find_call_stack_args): Likewise.
	* dse.c (record_store): Likewise.
	* dwarf2out.c (tls_mem_loc_descriptor, dw_sra_loc_expr): Likewise.
	* print-rtl.c (rtx_writer::print_rtx): Likewise.
	* read-rtl-function.c (test_loading_mem): Likewise.
	* rtlanal.c (may_trap_p_1): Likewise.
	* simplify-rtx.c (delegitimize_mem_from_attrs): Likewise.
	* var-tracking.c (int_mem_offset, track_expr_p): Likewise.
	* emit-rtl.c (mem_attrs_eq_p, get_mem_align_offset): Likewise.
	(mem_attrs::mem_attrs): New function.
	(set_mem_attributes_minus_bitpos): Change bitpos from a
	HOST_WIDE_INT to poly_int64.
	(set_mem_alias_set, set_mem_addr_space, set_mem_align, set_mem_expr)
	(clear_mem_offset, clear_mem_size, change_address)
	(get_spill_slot_decl, set_mem_attrs_for_spill): Directly
	initialize mem_attrs.
	(set_mem_offset, set_mem_size, adjust_address_1)
	(adjust_automodify_address_1, offset_address, widen_memory_access):
	Likewise.  Take poly_int64s rather than HOST_WIDE_INT.

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

From-SVN: r255875

1 files changed, 4 insertions, 2 deletions

diff --git a/gcc/rtl.h b/gcc/rtl.h
index ed944a4..408298a 100644
--- a/gcc/rtl.h
+++ b/gcc/rtl.h
@@ -147,6 +147,8 @@ struct addr_diff_vec_flags
    they cannot be modified in place.  */
 struct GTY(()) mem_attrs
 {
+  mem_attrs ();
+
   /* The expression that the MEM accesses, or null if not known.
      This expression might be larger than the memory reference itself.
      (In other words, the MEM might access only part of the object.)  */
@@ -154,11 +156,11 @@ struct GTY(()) mem_attrs
 
   /* The offset of the memory reference from the start of EXPR.
      Only valid if OFFSET_KNOWN_P.  */
-  HOST_WIDE_INT offset;
+  poly_int64 offset;
 
   /* The size of the memory reference in bytes.  Only valid if
      SIZE_KNOWN_P.  */
-  HOST_WIDE_INT size;
+  poly_int64 size;
 
   /* The alias set of the memory reference.  */
   alias_set_type alias;