introduce a new computation (that might also need casting the
variable to unsigned and back). */
if (cand->pos == IP_ORIGINAL
- && TREE_CODE (use->stmt) == MODIFY_EXPR
- && TREE_OPERAND (use->stmt, 0) == cand->var_after)
+ && cand->incremented_at == use->stmt)
{
+ tree step, ctype, utype;
+ enum tree_code incr_code = PLUS_EXPR;
+
+ gcc_assert (TREE_CODE (use->stmt) == MODIFY_EXPR);
+ gcc_assert (TREE_OPERAND (use->stmt, 0) == cand->var_after);
+
+ step = cand->iv->step;
+ ctype = TREE_TYPE (step);
+ utype = TREE_TYPE (cand->var_after);
+ if (TREE_CODE (step) == NEGATE_EXPR)
+ {
+ incr_code = MINUS_EXPR;
+ step = TREE_OPERAND (step, 0);
+ }
+
+ /* Check whether we may leave the computation unchanged.
+ This is the case only if it does not rely on other
+ computations in the loop -- otherwise, the computation
+ we rely upon may be removed in remove_unused_ivs,
+ thus leading to ICE. */
op = TREE_OPERAND (use->stmt, 1);
+ if (TREE_CODE (op) == PLUS_EXPR
+ || TREE_CODE (op) == MINUS_EXPR)
+ {
+ if (TREE_OPERAND (op, 0) == cand->var_before)
+ op = TREE_OPERAND (op, 1);
+ else if (TREE_CODE (op) == PLUS_EXPR
+ && TREE_OPERAND (op, 1) == cand->var_before)
+ op = TREE_OPERAND (op, 0);
+ else
+ op = NULL_TREE;
+ }
+ else
+ op = NULL_TREE;
- /* Be a bit careful. In case variable is expressed in some
- complicated way, rewrite it so that we may get rid of this
- complicated expression. */
- if ((TREE_CODE (op) == PLUS_EXPR
- || TREE_CODE (op) == MINUS_EXPR)
- && TREE_OPERAND (op, 0) == cand->var_before
- && TREE_CODE (TREE_OPERAND (op, 1)) == INTEGER_CST)
+ if (op
+ && (TREE_CODE (op) == INTEGER_CST
+ || operand_equal_p (op, step, 0)))
return;
+
+ /* Otherwise, add the necessary computations to express
+ the iv. */
+ op = fold_convert (ctype, cand->var_before);
+ comp = fold_convert (utype,
+ build2 (incr_code, ctype, op,
+ unshare_expr (step)));
}
+ else
+ comp = get_computation (data->current_loop, use, cand);
- comp = get_computation (data->current_loop, use, cand);
switch (TREE_CODE (use->stmt))
{
case PHI_NODE: