On 07/20/2016 11:51 AM, James Greenhalgh wrote:
2016-07-20 James Greenhalgh <[email protected]>
* target.def (max_noce_ifcvt_seq_cost): New.
* doc/tm.texi.in (TARGET_MAX_NOCE_IFCVT_SEQ_COST): Document it.
* doc/tm.texi: Regenerate.
* targhooks.h (default_max_noce_ifcvt_seq_cost): New.
* targhooks.c (default_max_noce_ifcvt_seq_cost): New.
* params.def (PARAM_MAX_RTL_IF_CONVERSION_PREDICTABLE_COST): New.
(PARAM_MAX_RTL_IF_CONVERSION_UNPREDICTABLE_COST): Likewise.
* doc/invoke.texi: Document new params.
I think this is starting to look like a clear improvement, so I'll ack
patches 1-3 with a few minor comments, and with the expectation that
you'll address performance regressions on other targets if they occur.
Number 4 I still need to figure out.
Minor details:
+ if (!speed_p)
+ {
+ return cost <= if_info->original_cost;
+ }
No braces around single statements in ifs. There's an instance of this
in patch 4 as well.
+ if (global_options_set.x_param_values[param])
+ return PARAM_VALUE (param);
How about wrapping the param value into COSTS_N_INSNS, to make the value
of the param less dependent on compiler internals?
In patch 4:
+ /* Check that our new insn isn't going to clobber ORIG_OTHER_DEST. */
+ bool modified_in_x = (set_tmp != NULL_RTX)
+ && modified_in_p (orig_other_dest, set_tmp);
Watch line wrapping. No parens around the first subexpression (there are
other examples of unnecessary ones in invocations of noce_arith_helper),
but around the full one.
Bernd
