Hi!
> This is just an initial patch and tries to optimize integer type power 2
> constants. I wanted to get feedback on this . I bootstrapped and reg
> tested on aarch64-none-linux-gnu .
Thanks for working on it.
ChangeLog entry for the patch is missing, probably also some testcases.
> @@ -90,6 +94,7 @@ static vect_recog_func_ptr
> vect_vect_recog_func_ptrs[NUM_PATTERNS] = {
> vect_recog_rotate_pattern,
> vect_recog_vector_vector_shift_pattern,
> vect_recog_divmod_pattern,
> + vect_recog_multconst_pattern,
> vect_recog_mixed_size_cond_pattern,
> vect_recog_bool_pattern};
Please watch formatting, the other lines are tab indented, so please use a
tab rather than 8 spaces.
> @@ -2147,6 +2152,87 @@ vect_recog_vector_vector_shift_pattern (vec<gimple>
> *stmts,
> return pattern_stmt;
> }
>
Function comment is missing here.
> +static gimple
> +vect_recog_multconst_pattern (vec<gimple> *stmts,
> + tree *type_in, tree *type_out)
About the function name, wonder if just vect_recog_mult_pattern wouldn't be
enough.
> + rhs_code = gimple_assign_rhs_code (last_stmt);
> + switch (rhs_code)
> + {
> + case MULT_EXPR:
> + break;
> + default:
> + return NULL;
> + }
This looks too weird, I'd just do
if (gimple_assign_rhs_code (last_stmt) != MULT_EXPR)
return NULL;
(you handle just one pattern).
> + /* If the target can handle vectorized multiplication natively,
> + don't attempt to optimize this. */
> + optab = optab_for_tree_code (rhs_code, vectype, optab_default);
Supposedly you can use MULT_EXPR directly here.
> + /* If target cannot handle vector left shift then we cannot
> + optimize and bail out. */
> + optab = optab_for_tree_code (LSHIFT_EXPR, vectype, optab_vector);
> + if (!optab
> + || optab_handler (optab, TYPE_MODE (vectype)) == CODE_FOR_nothing)
> + return NULL;
> +
> + if (integer_pow2p (oprnd1))
> + {
> + /* Pattern detected. */
> + if (dump_enabled_p ())
> + dump_printf_loc (MSG_NOTE, vect_location,
> + "vect_recog_multconst_pattern: detected:\n");
> +
> + tree shift;
> + shift = build_int_cst (itype, tree_log2 (oprnd1));
> + pattern_stmt = gimple_build_assign (vect_recog_temp_ssa_var (itype,
> NULL),
> + LSHIFT_EXPR, oprnd0, shift);
> + if (dump_enabled_p ())
> + dump_gimple_stmt_loc (MSG_NOTE, vect_location, TDF_SLIM, pattern_stmt,
> + 0);
> + stmts->safe_push (last_stmt);
> + *type_in = vectype;
> + *type_out = vectype;
> + return pattern_stmt;
> + }
Trailing whitespace.
The integer_pow2p case (have you checked signed multiply by INT_MIN?)
is only one of the cases you can actually handle, you can look at
expand_mult for many other cases - e.g. multiplication by negated powers of
2, or call choose_mult_variant and handle whatever it returns.
Jakub
