From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from [87.239.111.99] (localhost [127.0.0.1]) by dev.tarantool.org (Postfix) with ESMTP id 5A3226ECCD; Wed, 29 Jul 2026 10:32:08 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 dev.tarantool.org 5A3226ECCD DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tarantool.org; s=dev; t=1785310328; bh=xI0nJQPZyJqwNnfJVt0O+iu6ossjFoVUV+CV4wxljqU=; h=Date:To:References:In-Reply-To:Subject:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=KZ1o9PwjRZhKNQ8baRVkGBg9qAjuC07qBEXgdrCLpN4WbUIXedH9Vw7AoNPhOYkqS kCG5bby/XBMHodFbbUf9KycoYF8nBsdOP9cSNA3xCrlE9fNOzCV3kf0/9Cv46TYpiX CfhkA7P5PgdMFXF4dx7H22QGVQ/3yOFeJa5oEbNs= Received: from send217.i.mail.ru (send217.i.mail.ru [95.163.59.56]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 608FD6ECCD for ; Wed, 29 Jul 2026 10:32:06 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 dev.tarantool.org 608FD6ECCD Received: by exim-smtp-6c76488b9f-8fmhw with esmtpa (envelope-from ) id 1woylp-00000000Xts-1nHv; Wed, 29 Jul 2026 10:32:05 +0300 Date: Wed, 29 Jul 2026 10:31:49 +0300 To: Evgeniy Temirgaleev Message-ID: References: <1785262820.423211546@f512.i.mail.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1785262820.423211546@f512.i.mail.ru> X-Mailru-Src: smtp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eAau8CL7WIMRKs4sN3D3tLDjz0dLbV79QFUyzQ2Ujvy7cMT6pYYqY16iZVKkSc3dCLJ7zSJH7+u4VD18S7Vl4ZUrpaVfd2+vE6kuoey4m4VkSEu53w8ahmwBjZKM/YPHZyZHvz5uv+WouB9+ObcCpyrx6l7KImUglyhkEat/+ysWwi0gdhEs0JGjl6ggRWTy1haxBpVdbIX1nthFXMZebaIdHP2ghjoIc/363UZI6Kf1ptIMVczkDsfooUjfejjTfG+LL7Y= X-Mailru-Sender: 520A125C2F17F0B17094CDC02B85F11BE3D6B630C49E41A83DE06ABAFEAF6705829A72EBDC1A69A5B7CBEF92542CD7C88B0A2698F12F5C9EC77752E0C033A69E86920BD37369036789A8C6A0E60D2BB63A5DB60FBEB33A8A0DA7A0AF5A3A8387 X-Mras: Ok Subject: Re: [Tarantool-patches] [PATCH luajit 1/2] ARM64: Make tobit conversions match JIT backend behavior. X-BeenThere: tarantool-patches@dev.tarantool.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Sergey Kaplun via Tarantool-patches Reply-To: Sergey Kaplun Cc: tarantool-patches@dev.tarantool.org Errors-To: tarantool-patches-bounces@dev.tarantool.org Sender: "Tarantool-patches" Hi, Evgeniy! Thanks for the review. Please consider my answers below. On 28.07.26, Evgeniy Temirgaleev wrote: > Hi, Sergey! Thanks for the patch! > > LGTM with a comment, please see below. > > -- > Best regards, > Evgeniy Temirgaleev > > > > > From: Sergey Kaplun > > To: Sergey Bronnikov , Evgeniy Temirgaleev > > > > Cc: tarantool-patches@dev.tarantool.org, Sergey Kaplun > > > > Date: Tuesday, July 21, 2026 5:53 PM +03:00 > > From: Mike Pall > > > > Thanks to Peter Cawley. > > > > (cherry picked from commit cdc2db3aeac442e139c3b1fda715fdfa78da8791) > > > > On the aarch64 architecture, the `tobit()` function incorrectly > > truncates instead of rounding to the nearest integer. This leads to > > inconsistency between various VMs (comparing to x86/x64, for example) > > and between the arm64 VM and JIT. > > > > This patch uses an addition of 2^52 + 2^51 constant to the given > > argument to convert it to the nearest integer value. After reading the > > lowest 32 bits of the register, we get the expected result. > > > > Sergey Kaplun: > > * added the description and the test for the problem > > > > Part of tarantool/tarantool#12880 > > --- > > src/vm_arm64.dasc | 20 ++++--------- > > .../lj-1253-tobit-conversion.test.lua | 28 +++++++++++++++++++ > > 2 files changed, 34 insertions(+), 14 deletions(-) > > create mode 100644 test/tarantool-tests/lj-1253-tobit-conversion.test.lua > > > > diff --git a/src/vm_arm64.dasc b/src/vm_arm64.dasc > > index 57131140..4ffd7378 100644 > > --- a/src/vm_arm64.dasc > > +++ b/src/vm_arm64.dasc > > diff --git a/test/tarantool-tests/lj-1253-tobit-conversion.test.lua > > b/test/tarantool-tests/lj-1253-tobit-conversion.test.lua > > new file mode 100644 > > index 00000000..31cf97ca > > --- /dev/null > > +++ b/test/tarantool-tests/lj-1253-tobit-conversion.test.lua > > @@ -0,0 +1,28 @@ > > +local tap = require('tap') > > + > > +-- Test file to demonstrate LuaJIT's incorrect bit.tobit > > +-- behaviour for arm64. > > +-- See also: https://github.com/LuaJIT/LuaJIT/issues/1253. > > + > > +local test = tap.test('lj-1253-tobit-conversion') > > + > > +test:plan(2) > > + > > +test:is(bit.tobit(1.7), 2, 'correct bit.tobit rounding') > > > > I suppose, what Sergey Bronnikov proposes adding parentheses in the messages also. Here, Maybe, but we use parentheses only in the comments AFAICS: | grep "test:\(ok\|is\|match\|samevalues\).*'.*\`" -R test/tarantool-tests/ | wc -l | 0 And there are examples of mentioning the functions in the test names: | test/tarantool-tests/lj-928-int-min-negation.test.lua:test:is(tonumber('-0x80000000'), INT32_MIN, 'no UB during strscan_hex') | test/tarantool-tests/lj-928-int-min-negation.test.lua:test:is(tonumber('-0b10000000000000000000000000000000'), INT32_MIN, | test/tarantool-tests/lj-928-int-min-negation.test.lua:test:is(tonumber('-2147483648'), INT32_MIN, 'no UB during strscan_scan') So, this part is ignored. > > > > + > > +test:skipcond({ > > + ['Test requires JIT enabled'] = not jit.status(), > > +}) > > + > > +local results = {} > > + > > +jit.opt.start('hotloop=1') > > + > > +for i = 1, 4 do > > + -- Use constants on trace. > > + results[i] = bit.tobit(1.7) > > +end > > + > > +test:samevalues(results, 'consistent JIT and VM behaviour for bit.tobit') > > > > > > and here. Ditto. > > > > > + > > +test:done(true) > > -- > > 2.55.0 > > -- Best regards, Sergey Kaplun