[PATCH] Add XINSN macro and use it within NEXT_INSN/PREV_INSN (was Re: [PATCH] Force rtl templates to be inlined)
Fri Sep 5 18:45:00 GMT 2014
On 09/04/14 14:04, David Malcolm wrote:
> On Tue, 2014-09-02 at 19:50 +0200, Andi Kleen wrote:
>>> I suspect the bulk of them currently are coming from the safe_as_a
>>> <rtx_insn *> calls within NEXT_INSN and PREV_INSN; do you happen to have
>>> information handy on that?
>> Yes that's right:
>> - 1.03% lto1 [.] bool is_a_helper<rtx_insn*>::test<rtx_def>(rtx_def*) â
>> - bool is_a_helper<rtx_insn*>::test<rtx_def>(rtx_def*) â
>> - 92.20% bool is_a<rtx_insn*, rtx_def>(rtx_def*) â
>> - 98.53% rtx_insn* safe_as_a<rtx_insn*, rtx_def>(rtx_def*) â
>> - 73.28% NEXT_INSN(rtx_insn const*) â
> The is_a_helper for rtx_insn * is non-trivial, so it may be worth
> avoiding it, even when inlined.
> The attached patch rewrites the inline NEXT_INSN/PREV_INSN to avoid
> doing the safe_as_a, instead tightening up the interface so that one can
> only set them to an insn, and introducing a new XINSN access macro and
> corresponding rt_insn member of the union.
> Bootstrapped on x86_64-unknown-linux-gnu (Fedora 20), and has been
> rebuilt as part of a config-list.mk build for all working configurations
> (albeit with other patches for the latter case).
> OK for trunk?
So is this just to deal with the overhead in the safe_as_a helper until
we can strengthen more code? And is that overhead significant in an
Would an alternate approach be to make the checking in safe_as_a
conditionalized on ENABLE_CHECKING?
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