return changed;
}
+/* If OPCODE is BIT_IOR_EXPR or BIT_AND_EXPR and CURR is a comparison
+ expression, examine the other OPS to see if any of them are comparisons
+ of the same values, which we may be able to combine or eliminate.
+ For example, we can rewrite (a < b) | (a == b) as (a <= b). */
+
+static bool
+eliminate_redundant_comparison (enum tree_code opcode,
+ VEC (operand_entry_t, heap) **ops,
+ unsigned int currindex,
+ operand_entry_t curr)
+{
+ tree op1, op2;
+ enum tree_code lcode, rcode;
+ gimple def1, def2;
+ int i;
+ operand_entry_t oe;
+
+ if (opcode != BIT_IOR_EXPR && opcode != BIT_AND_EXPR)
+ return false;
+
+ /* Check that CURR is a comparison. */
+ if (TREE_CODE (curr->op) != SSA_NAME)
+ return false;
+ def1 = SSA_NAME_DEF_STMT (curr->op);
+ if (!is_gimple_assign (def1))
+ return false;
+ lcode = gimple_assign_rhs_code (def1);
+ if (TREE_CODE_CLASS (lcode) != tcc_comparison)
+ return false;
+ op1 = gimple_assign_rhs1 (def1);
+ op2 = gimple_assign_rhs2 (def1);
+
+ /* Now look for a similar comparison in the remaining OPS. */
+ for (i = currindex + 1;
+ VEC_iterate (operand_entry_t, *ops, i, oe);
+ i++)
+ {
+ tree t;
+
+ if (TREE_CODE (oe->op) != SSA_NAME)
+ continue;
+ def2 = SSA_NAME_DEF_STMT (oe->op);
+ if (!is_gimple_assign (def2))
+ continue;
+ rcode = gimple_assign_rhs_code (def2);
+ if (TREE_CODE_CLASS (rcode) != tcc_comparison)
+ continue;
+ if (operand_equal_p (op1, gimple_assign_rhs1 (def2), 0)
+ && operand_equal_p (op2, gimple_assign_rhs2 (def2), 0))
+ ;
+ else if (operand_equal_p (op1, gimple_assign_rhs2 (def2), 0)
+ && operand_equal_p (op2, gimple_assign_rhs1 (def2), 0))
+ rcode = swap_tree_comparison (rcode);
+ else
+ continue;
+
+ /* If we got here, we have a match. See if we can combine the
+ two comparisons. */
+ t = combine_comparisons (UNKNOWN_LOCATION,
+ (opcode == BIT_IOR_EXPR
+ ? TRUTH_OR_EXPR : TRUTH_AND_EXPR),
+ lcode, rcode, TREE_TYPE (curr->op), op1, op2);
+ if (!t)
+ continue;
+ if (dump_file && (dump_flags & TDF_DETAILS))
+ {
+ fprintf (dump_file, "Equivalence: ");
+ print_generic_expr (dump_file, curr->op, 0);
+ fprintf (dump_file, " %s ", op_symbol_code (opcode));
+ print_generic_expr (dump_file, oe->op, 0);
+ fprintf (dump_file, " -> ");
+ print_generic_expr (dump_file, t, 0);
+ fprintf (dump_file, "\n");
+ }
+
+ /* Now we can delete oe, as it has been subsumed by the new combined
+ expression t. */
+ VEC_ordered_remove (operand_entry_t, *ops, i);
+ reassociate_stats.ops_eliminated ++;
+
+ /* If t is the same as curr->op, we're done. Otherwise we must
+ replace curr->op with t. Special case is if we got a constant
+ back, in which case we add it to the end instead of in place of
+ the current entry. */
+ if (TREE_CODE (t) == INTEGER_CST)
+ {
+ VEC_ordered_remove (operand_entry_t, *ops, currindex);
+ add_to_ops_vec (ops, t);
+ }
+ else if (TREE_CODE (t) != lcode)
+ {
+ tree tmpvar;
+ gimple sum;
+ enum tree_code subcode;
+ tree newop1;
+ tree newop2;
+ tmpvar = create_tmp_var (TREE_TYPE (t), NULL);
+ add_referenced_var (tmpvar);
+ extract_ops_from_tree (t, &subcode, &newop1, &newop2);
+ sum = build_and_add_sum (tmpvar, newop1, newop2, subcode);
+ curr->op = gimple_get_lhs (sum);
+ }
+ return true;
+ }
+
+ return false;
+}
/* Perform various identities and other optimizations on the list of
operand entries, stored in OPS. The tree code for the binary
if (eliminate_not_pairs (opcode, ops, i, oe))
return;
if (eliminate_duplicate_pair (opcode, ops, &done, i, oe, oelast)
- || (!done && eliminate_plus_minus_pair (opcode, ops, i, oe)))
+ || (!done && eliminate_plus_minus_pair (opcode, ops, i, oe))
+ || (!done && eliminate_redundant_comparison (opcode, ops, i, oe)))
{
if (done)
return;
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