* Building libgccjit with -fno-semantic-interposition? ( was Re: 1.76% performance loss in VRP due to inlining) [not found] ` <179E65E4-33E7-45F1-A7B3-755CA434D037@gmail.com> @ 2024-04-30 21:48 ` David Malcolm 2024-05-02 7:40 ` Andrea Corallo 0 siblings, 1 reply; 3+ messages in thread From: David Malcolm @ 2024-04-30 21:48 UTC (permalink / raw) To: Richard Biener, Jason Merrill Cc: Aldy Hernandez, GCC Mailing List, MacLeod, Andrew, Antoni Boucher, Andrea Corallo, jit On Tue, 2024-04-30 at 21:15 +0200, Richard Biener via Gcc wrote: > > > > Am 30.04.2024 um 21:11 schrieb Jason Merrill via Gcc > > <gcc@gcc.gnu.org>: > > > > On Fri, Apr 26, 2024 at 5:44 AM Aldy Hernandez via Gcc > > <gcc@gcc.gnu.org> wrote: > > > > > > In implementing prange (pointer ranges), I have found a 1.74% > > > slowdown > > > in VRP, even without any code path actually using the code. I > > > have > > > tracked this down to irange::get_bitmask() being compiled > > > differently > > > with and without the bare bones patch. With the patch, > > > irange::get_bitmask() has a lot of code inlined into it, > > > particularly > > > get_bitmask_from_range() and consequently the wide_int_storage > > > code. > > ... > > > +static irange_bitmask > > > +get_bitmask_from_range (tree type, > > > + const wide_int &min, const wide_int &max) > > ... > > > -irange_bitmask > > > -irange::get_bitmask_from_range () const > > > > My guess is that this is the relevant change: the old function has > > external linkage, and is therefore interposable, which inhibits > > inlining. The new function has internal linkage, which allows > > inlining. > > > > Relatedly, I wonder if we want to build GCC with -fno-semantic- > > interposition? > > I guess that’s a good idea, though it’s already implied when doing > LTO bootstrap and building cc1 and friends? (But not for libgccjit?) [CCing jit mailing list] FWIW I've no idea if any libgccjit users are using semantic interposition; I suspect the answer is "no one is using it". Antoyo, Andrea [also CCed]: are either of you using semantic interposition of symbols within libgccjit? If not, we *might* get a slightly faster libgccjit by building it with -fno-semantic-interposition. Or maybe not... Dave > > Richard > > > > > Jason > > > ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Building libgccjit with -fno-semantic-interposition? ( was Re: 1.76% performance loss in VRP due to inlining) 2024-04-30 21:48 ` Building libgccjit with -fno-semantic-interposition? ( was Re: 1.76% performance loss in VRP due to inlining) David Malcolm @ 2024-05-02 7:40 ` Andrea Corallo 2024-06-10 10:59 ` Sam James 0 siblings, 1 reply; 3+ messages in thread From: Andrea Corallo @ 2024-05-02 7:40 UTC (permalink / raw) To: David Malcolm, Richard Biener, Jason Merrill Cc: Aldy Hernandez, GCC Mailing List, MacLeod, Andrew, Antoni Boucher, jit > FWIW I've no idea if any libgccjit users are using semantic > interposition; I suspect the answer is "no one is using it". > > Antoyo, Andrea [also CCed]: are either of you using semantic > interposition of symbols within libgccjit? Hi David, AFAIU in Emacs we are not relying on interposition of symbols. Thanks Andrea ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Building libgccjit with -fno-semantic-interposition? ( was Re: 1.76% performance loss in VRP due to inlining) 2024-05-02 7:40 ` Andrea Corallo @ 2024-06-10 10:59 ` Sam James 0 siblings, 0 replies; 3+ messages in thread From: Sam James @ 2024-06-10 10:59 UTC (permalink / raw) To: Andrea Corallo via Gcc Cc: David Malcolm, Richard Biener, Jason Merrill, Andrea Corallo, Aldy Hernandez, MacLeod, Andrew, Antoni Boucher, jit Andrea Corallo via Gcc <gcc@gcc.gnu.org> writes: >> FWIW I've no idea if any libgccjit users are using semantic >> interposition; I suspect the answer is "no one is using it". >> >> Antoyo, Andrea [also CCed]: are either of you using semantic >> interposition of symbols within libgccjit? > > Hi David, > > AFAIU in Emacs we are not relying on interposition of symbols. FWIW, I've built GCC (inc. libgccjit for Emacs) with -fno-semantic-interposition for a few years now and had no issues. It's worth considering, I think, given the above. > > Thanks > > Andrea ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2024-06-10 10:59 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <CADzB+2=ptBaKFMj3zJgh-UM9Zuh0B8_RRmfVZhBESRFhkGQspA@mail.gmail.com> [not found] ` <179E65E4-33E7-45F1-A7B3-755CA434D037@gmail.com> 2024-04-30 21:48 ` Building libgccjit with -fno-semantic-interposition? ( was Re: 1.76% performance loss in VRP due to inlining) David Malcolm 2024-05-02 7:40 ` Andrea Corallo 2024-06-10 10:59 ` Sam James
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