diff options
Diffstat (limited to 'gcc/tree-ssa-loop-ivopts.c')
| -rw-r--r-- | gcc/tree-ssa-loop-ivopts.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c index 436e6ce..74dadf7 100644 --- a/gcc/tree-ssa-loop-ivopts.c +++ b/gcc/tree-ssa-loop-ivopts.c @@ -4089,6 +4089,7 @@ determine_use_iv_cost_condition (struct ivopts_data *data, bitmap depends_on_elim = NULL, depends_on_express = NULL, depends_on; comp_cost elim_cost, express_cost, cost; bool ok; + tree *control_var, *bound_cst; /* Only consider real candidates. */ if (!cand->iv) @@ -4110,9 +4111,21 @@ determine_use_iv_cost_condition (struct ivopts_data *data, /* Try expressing the original giv. If it is compared with an invariant, note that we cannot get rid of it. */ - ok = extract_cond_operands (data, use->stmt, NULL, NULL, NULL, &cmp_iv); + ok = extract_cond_operands (data, use->stmt, &control_var, &bound_cst, + NULL, &cmp_iv); gcc_assert (ok); + /* When the condition is a comparison of the candidate IV against + zero, prefer this IV. + + TODO: The constant that we're substracting from the cost should + be target-dependent. This information should be added to the + target costs for each backend. */ + if (integer_zerop (*bound_cst) + && (operand_equal_p (*control_var, cand->var_after, 0) + || operand_equal_p (*control_var, cand->var_before, 0))) + elim_cost.cost -= 1; + express_cost = get_computation_cost (data, use, cand, false, &depends_on_express, NULL); fd_ivopts_data = data; |