+/* The regular frag_offset_fixed_p doesn't work for rs_align_test
+ frags. */
+
+static bfd_boolean
+align_test_frag_offset_fixed_p (const fragS *frag1, const fragS *frag2,
+ bfd_vma *offset)
+{
+ const fragS *frag;
+ bfd_vma off;
+
+ /* Start with offset initialised to difference between the two frags.
+ Prior to assigning frag addresses this will be zero. */
+ off = frag1->fr_address - frag2->fr_address;
+ if (frag1 == frag2)
+ {
+ *offset = off;
+ return TRUE;
+ }
+
+ /* Maybe frag2 is after frag1. */
+ frag = frag1;
+ while (frag->fr_type == rs_fill
+ || frag->fr_type == rs_align_test)
+ {
+ if (frag->fr_type == rs_fill)
+ off += frag->fr_fix + frag->fr_offset * frag->fr_var;
+ else
+ off += frag->fr_fix;
+ frag = frag->fr_next;
+ if (frag == NULL)
+ break;
+ if (frag == frag2)
+ {
+ *offset = off;
+ return TRUE;
+ }
+ }
+
+ /* Maybe frag1 is after frag2. */
+ off = frag1->fr_address - frag2->fr_address;
+ frag = frag2;
+ while (frag->fr_type == rs_fill
+ || frag->fr_type == rs_align_test)
+ {
+ if (frag->fr_type == rs_fill)
+ off -= frag->fr_fix + frag->fr_offset * frag->fr_var;
+ else
+ off -= frag->fr_fix;
+ frag = frag->fr_next;
+ if (frag == NULL)
+ break;
+ if (frag == frag1)
+ {
+ *offset = off;
+ return TRUE;
+ }
+ }
+
+ return FALSE;
+}
+
+/* Optimize a difference of symbols which have rs_align_test frag if
+ possible. */
+
+int
+sh_optimize_expr (expressionS *l, operatorT op, expressionS *r)
+{
+ bfd_vma frag_off;
+
+ if (op == O_subtract
+ && l->X_op == O_symbol
+ && r->X_op == O_symbol
+ && S_GET_SEGMENT (l->X_add_symbol) == S_GET_SEGMENT (r->X_add_symbol)
+ && (SEG_NORMAL (S_GET_SEGMENT (l->X_add_symbol))
+ || r->X_add_symbol == l->X_add_symbol)
+ && align_test_frag_offset_fixed_p (symbol_get_frag (l->X_add_symbol),
+ symbol_get_frag (r->X_add_symbol),
+ &frag_off))
+ {
+ offsetT symval_diff = S_GET_VALUE (l->X_add_symbol)
+ - S_GET_VALUE (r->X_add_symbol);
+ subtract_from_result (l, r->X_add_number, r->X_extrabit);
+ subtract_from_result (l, frag_off / OCTETS_PER_BYTE, 0);
+ add_to_result (l, symval_diff, symval_diff < 0);
+ l->X_op = O_constant;
+ l->X_add_symbol = 0;
+ return 1;
+ }
+ return 0;
+}
+#endif /* OBJ_ELF */