From: Maksim Kokryashkin via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: tarantool-patches@dev.tarantool.org, imun@tarantool.org, skaplun@tarantool.org Subject: [Tarantool-patches] [PATCH luajit v2] Fix narrowing of unary minus. Date: Tue, 20 Sep 2022 14:16:45 +0300 [thread overview] Message-ID: <20220920111649.86190-1-max.kokryashkin@gmail.com> (raw) In-Reply-To: <YyJQZUUa41uwJcL1@root> From: Mike Pall <mike> (cherry picked from commit 1e6e8aaa20626ac94cf907c69b0452f76e9f5fa5) LuaJIT narrowing optimization during BC_UNM recording may ignore information about sign of zero for integer types of IR. So far the resulting value on a trace is not the same as for the interpreter. However, in DUALNUM mode with using of TValues containing integers the -0 value is represented in the same way as the 0 value and there is no difference between them. This patch fixes the non-DUALNUM mode behaviour. When the zero value is identified during recording it should be cast to number so IR_CONV is emitted. Also, this patch adds assertion guard checking that value on which operation of unary minus is performed isn't zero. Maxim Kokryashkin: * added the description and the test for the problem Resolves tarantool/tarantool#6976 Part of tarantool/tarantool#7230 --- Changes in v2: - Fixed test and commit message as per review by Sergey Branch and PR are updated. src/lj_opt_narrow.c | 9 +++- .../gh-6976-narrowing-of-unary-minus.test.lua | 51 +++++++++++++++++++ 2 files changed, 58 insertions(+), 2 deletions(-) create mode 100644 test/tarantool-tests/gh-6976-narrowing-of-unary-minus.test.lua diff --git a/src/lj_opt_narrow.c b/src/lj_opt_narrow.c index cd96ca4b..bb61f97b 100644 --- a/src/lj_opt_narrow.c +++ b/src/lj_opt_narrow.c @@ -551,8 +551,13 @@ TRef lj_opt_narrow_unm(jit_State *J, TRef rc, TValue *vc) { rc = conv_str_tonum(J, rc, vc); if (tref_isinteger(rc)) { - if ((uint32_t)numberVint(vc) != 0x80000000u) - return emitir(IRTGI(IR_SUBOV), lj_ir_kint(J, 0), rc); + uint32_t k = (uint32_t)numberVint(vc); + if ((LJ_DUALNUM || k != 0) && k != 0x80000000u) { + TRef zero = lj_ir_kint(J, 0); + if (!LJ_DUALNUM) + emitir(IRTGI(IR_NE), rc, zero); + return emitir(IRTGI(IR_SUBOV), zero, rc); + } rc = emitir(IRTN(IR_CONV), rc, IRCONV_NUM_INT); } return emitir(IRTN(IR_NEG), rc, lj_ir_ksimd(J, LJ_KSIMD_NEG)); diff --git a/test/tarantool-tests/gh-6976-narrowing-of-unary-minus.test.lua b/test/tarantool-tests/gh-6976-narrowing-of-unary-minus.test.lua new file mode 100644 index 00000000..18778a55 --- /dev/null +++ b/test/tarantool-tests/gh-6976-narrowing-of-unary-minus.test.lua @@ -0,0 +1,51 @@ +local tap = require('tap') +local test = tap.test('gh-6976-narrowing-of-unary-minus') +test:plan(2) + +jit.opt.start('hotloop=1', 'hotexit=1') + +local function check(routine) + jit.off() + jit.flush() + local interp_res = routine() + jit.on() + local jit_res = routine() + + for i = 1, #interp_res do + if interp_res[i] ~= jit_res[i] then + return false + end + end + + return true +end + +test:ok( + check( + function() + local res = require('table.new')(3, 0) + for _ = 1, 3 do + local zero = 0 + zero = -zero + table.insert(res, tostring(zero)) + end + return res + end + ), + 'incorrect recording for zero' +) + +test:ok( + check( + function() + local res = require('table.new')(3, 0) + for i = 2, 0, -1 do + table.insert(res, tostring(-i)) + end + return res + end + ), + 'assertion guard fail' +) + +os.exit(test:check() and 0 or 1) -- 2.32.1 (Apple Git-133)
next prev parent reply other threads:[~2022-09-20 11:17 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-09-09 12:15 [Tarantool-patches] [PATCH luajit] " Maksim Kokryashkin via Tarantool-patches 2022-09-14 22:06 ` Sergey Kaplun via Tarantool-patches 2022-09-20 11:16 ` Maksim Kokryashkin via Tarantool-patches [this message] 2022-09-21 8:48 ` [Tarantool-patches] [PATCH luajit v2] " Sergey Kaplun via Tarantool-patches 2022-09-25 21:31 ` sergos via Tarantool-patches 2022-09-29 9:58 ` Maxim Kokryashkin via Tarantool-patches 2022-09-29 13:08 ` Sergey Kaplun via Tarantool-patches 2022-10-03 9:57 ` Maxim Kokryashkin via Tarantool-patches 2022-11-30 10:40 ` sergos via Tarantool-patches 2022-12-12 9:42 ` [Tarantool-patches] [PATCH luajit] " Igor Munkin via Tarantool-patches
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