diff options
Diffstat (limited to 'gcc/tree-ssa-loop-ivopts.c')
| -rw-r--r-- | gcc/tree-ssa-loop-ivopts.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/gcc/tree-ssa-loop-ivopts.c b/gcc/tree-ssa-loop-ivopts.c index bde68e7..a701636 100644 --- a/gcc/tree-ssa-loop-ivopts.c +++ b/gcc/tree-ssa-loop-ivopts.c @@ -3597,22 +3597,26 @@ get_shiftadd_cost (tree expr, machine_mode mode, comp_cost cost0, tree multop = TREE_OPERAND (mult, 0); int m = exact_log2 (int_cst_value (cst)); int maxm = MIN (BITS_PER_WORD, GET_MODE_BITSIZE (mode)); - int sa_cost; - bool equal_p = false; + int as_cost, sa_cost; + bool mult_in_op1; if (!(m >= 0 && m < maxm)) return false; - if (operand_equal_p (op1, mult, 0)) - equal_p = true; + mult_in_op1 = operand_equal_p (op1, mult, 0); + as_cost = add_cost (speed, mode) + shift_cost (speed, mode, m); + + /* If the target has a cheap shift-and-add or shift-and-sub instruction, + use that in preference to a shift insn followed by an add insn. */ sa_cost = (TREE_CODE (expr) != MINUS_EXPR ? shiftadd_cost (speed, mode, m) - : (equal_p + : (mult_in_op1 ? shiftsub1_cost (speed, mode, m) : shiftsub0_cost (speed, mode, m))); - res = new_cost (sa_cost, 0); - res = add_costs (res, equal_p ? cost0 : cost1); + + res = new_cost (MIN (as_cost, sa_cost), 0); + res = add_costs (res, mult_in_op1 ? cost0 : cost1); STRIP_NOPS (multop); if (!is_gimple_val (multop)) |