Launchpad has imported 10 comments from the remote bug at https://bugzilla.opensuse.org/show_bug.cgi?id=1204267.
If you reply to an imported comment from within Launchpad, your comment will be sent to the remote bug automatically. Read more about Launchpad's inter-bugtracker facilities at https://help.launchpad.net/InterBugTracking. ------------------------------------------------------------------------ On 2022-10-13T09:20:11+00:00 Guillaume Gardet wrote: Created attachment 862142 journal.log Plasmashell crashes on armv7 since snapshot 20221006. Oct 13 04:54:05 localhost.localdomain plasmashell[2046]: QFont::setPointSizeF: Point size <= 0 (0.000000), must be greater than 0 Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: LLVM ERROR: Cannot select: 0x3003d38: v4i32 = ARMISD::VCMPZ 0x2f64940, Constant:i32<2> Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: 0x2f64940: v4i32,ch = ARMISD::VLD1DUP<(load (s32) from %ir.326)> 0x2fcdea8, 0x2fb0848, Constant:i32<4> Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: 0x2fb0848: i32 = add 0x3006648, Constant:i32<64> Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: 0x3006648: i32,ch = CopyFromReg 0x2e4bf5c, Register:i32 %35 Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: 0x2fed080: i32 = Register %35 Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: 0x2e65f08: i32 = Constant<64> Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: 0x2fd93c0: i32 = Constant<4> Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: 0x2fd9690: i32 = Constant<2> Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: In function: fs_variant_partial Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: KCrash: Application 'plasmashell' crashing... Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: KCrash: Attempting to start /usr/libexec/drkonqi Oct 13 04:54:06 localhost.localdomain plasmashell[2077]: libEGL warning: DRI2: failed to authenticate Oct 13 04:54:06 localhost.localdomain kded5[1600]: Service "org.kde.StatusNotifierHost-2046" unregistered Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: Unable to start Dr. Konqi Oct 13 04:54:06 localhost.localdomain plasmashell[2046]: Re-raising signal for core dump handling. Oct 13 04:54:06 localhost.localdomain systemd[1284]: plasma-plasmashell.service: Main process exited, code=dumped, status=6/ABRT Reply at: https://bugs.launchpad.net/ubuntu/+source/llvm- toolchain-15/+bug/1993800/comments/0 ------------------------------------------------------------------------ On 2022-10-13T09:44:07+00:00 Fvogt-a wrote: It was probably introduced in 20221003, which didn't reach openQA for ARM. Unfortunately that contained both Mesa and llvm updates, so hard to tell what caused that. Reassigning. Reply at: https://bugs.launchpad.net/ubuntu/+source/llvm- toolchain-15/+bug/1993800/comments/1 ------------------------------------------------------------------------ On 2022-10-13T12:47:27+00:00 Sndirsch-u wrote: Honestly. No clue ... We switched to Mesa 22.2 and llvm15 lately. Reply at: https://bugs.launchpad.net/ubuntu/+source/llvm- toolchain-15/+bug/1993800/comments/2 ------------------------------------------------------------------------ On 2022-10-17T12:25:23+00:00 3-christophe wrote: The issue can be reproduced with one pyside test on armv7l: [ 3286s] 460/478 Test #461: QtDataVisualization_datavisualization_test ......Subprocess aborted***Exception: 0.82 sec [ 3286s] .LLVM ERROR: Cannot select: 0x1e6a2c0: v4i32 = ARMISD::VCMPZ 0x1d68a08, Constant:i32<2> [ 3286s] 0x1d68a08: v4i32,ch = ARMISD::VLD1DUP<(load (s32) from %ir.235)> 0x11ebd5c, 0x1d68660:1, Constant:i32<4> [ 3286s] 0x1d68660: i32,i32,ch = load<(load (s32) from %ir.232, align 8), <post-inc>> 0x11ebd5c, 0x1d52518, Constant:i32<64> [ 3286s] 0x1d52518: i32,ch = CopyFromReg 0x11ebd5c, Register:i32 %30 [ 3286s] 0x1d68858: i32 = Register %30 [ 3286s] 0x1d67100: i32 = Constant<64> [ 3286s] 0x1afd1a8: i32 = Constant<4> [ 3286s] 0x1d66ec0: i32 = Constant<2> [ 3286s] In function: fs_variant_partial Reply at: https://bugs.launchpad.net/ubuntu/+source/llvm- toolchain-15/+bug/1993800/comments/3 ------------------------------------------------------------------------ On 2022-10-18T21:04:21+00:00 Aaronpuchert wrote: In my understanding, "Cannot select" is always an LLVM bug, specifically in the backend. Early stages of the backend should "legalize" data types and instructions, sending to instruction selection only what the target supports. So I can have a look, but it would be appreciated if someone could extract the IR that Mesa sends to LLVM. Otherwise I'll have to reverse- engineer a reproducer. Nevertheless, some initial remarks: ARMISD::VCMPZ is a "Vector compare to zero." [1] It should correspond to "vcmpe" in assembly [2]. The first argument being a v4i32 is slightly suspicious. I would have expected a v4f32, but since they live in the same registers maybe the backend doesn't care. The second is a Constant:i32<2> = ARMCC::CondCodes::HS, corresponding to conditional execution only if the carry flag is set, if I understand this correctly. [3,4] Inside we have ARMISD::VLD1DUP, which is a "Vector load N-element structure to all lanes" (same file as [1], different line), and seems to correspond to "vld1.N" in assembly. [5] The Constant:i32<4> could be an alignment, but I'm not sure. [1] https://github.com/llvm/llvm-project/blob/llvmorg-15.0.2/llvm/lib/Target/ARM/ARMISelLowering.h#L148 [2] https://developer.arm.com/documentation/ddi0406/c/Application-Level-Architecture/Instruction-Details/Alphabetical-list-of-instructions/VCMP--VCMPE [3] https://developer.arm.com/documentation/ddi0406/c/Application-Level-Architecture/Instruction-Details/Conditional-execution [4] https://github.com/llvm/llvm-project/blob/llvmorg-15.0.2/llvm/lib/Target/ARM/Utils/ARMBaseInfo.h#L33 [5] https://developer.arm.com/documentation/ddi0406/c/Application-Level-Architecture/Instruction-Details/Alphabetical-list-of-instructions/VLD1--single-element-to-all-lanes- Reply at: https://bugs.launchpad.net/ubuntu/+source/llvm- toolchain-15/+bug/1993800/comments/4 ------------------------------------------------------------------------ On 2022-10-19T12:32:52+00:00 Fvogt-a wrote: Created attachment 862276 Various IR dumps of LLVM failure It can be reproduced by running /usr/lib/qt6/examples/datavisualization/bars/bars from the qt6-datavis3d-examples package as well. That has a slightly more complex shader though. I attached the full output of running it inside xvfb-run with GALLIVM_DEBUG=tgsi,ir,asm LP_DEBUG=fs, which dumps all kind of info, including LLVM IR. Reply at: https://bugs.launchpad.net/ubuntu/+source/llvm- toolchain-15/+bug/1993800/comments/5 ------------------------------------------------------------------------ On 2022-10-19T21:34:01+00:00 Aaronpuchert wrote: Thanks, that should help. This isn't my area of expertise, but at least we can use this to file a bug upstream. (In reply to Aaron Puchert from comment #4) > Nevertheless, some initial remarks: ARMISD::VCMPZ is a "Vector compare to > zero." [1] It should correspond to "vcmpe" in assembly [2]. The first > argument being a v4i32 is slightly suspicious. I would have expected a > v4f32, but since they live in the same registers maybe the backend doesn't > care. The second is a Constant:i32<2> = ARMCC::CondCodes::HS, corresponding > to conditional execution only if the carry flag is set, if I understand this > correctly. [3,4] Seems I was misreading that, the condition code is for the comparison itself. For floating-point ARMCC::CondCodes::HS means ">, ==, or unordered", so we're doing a !(... < 0.0f) comparison. Likely corresponds to one of the fcmp ..., zeroinitializer in the IR. Reply at: https://bugs.launchpad.net/ubuntu/+source/llvm- toolchain-15/+bug/1993800/comments/6 ------------------------------------------------------------------------ On 2022-10-20T08:17:13+00:00 Fvogt-a wrote: (In reply to Aaron Puchert from comment #6) > Thanks, that should help. This isn't my area of expertise, but at least we > can use this to file a bug upstream. Will you do that or should one of us take care of that? Reply at: https://bugs.launchpad.net/ubuntu/+source/llvm- toolchain-15/+bug/1993800/comments/7 ------------------------------------------------------------------------ On 2022-10-21T02:32:58+00:00 Aaronpuchert wrote: Since I'm not sure what the precise target machine is, I've used flags similar to how we build LLVM itself (see the specfile): llc -march=arm --float-abi=hard -mattr=+armv7-a,+vfp3d16 This reproduces the crash, just with a slightly different message: LLVM ERROR: Cannot select: t933: v4i32 = ARMISD::VCMPZ t1307, Constant:i32<2> t1307: v4i32,ch = ARMISD::VLD1DUP<(load (s32) from %ir.584)> t0, t1429:1, Constant:i32<4> t1429: i32,i32,ch = load<(load (s32) from %ir."&context.constants_ptr[]5618", align 8), <post-inc>> t0, t2, Constant:i32<64> t2: i32,ch = CopyFromReg t0, Register:i32 %45 t1: i32 = Register %45 t212: i32 = Constant<64> t49: i32 = Constant<4> t28: i32 = Constant<2> What's different is the added IR names, but they're not immediately helpful: there is a "&context.constants_ptr[]56" in the source, maybe there was disambiguation. The crash is reproducible on the current main branch, so it's still not fixed. With bugpoint --run-llc <input-file> --tool-args <options as above> we can reduce it to this: define void @fs_variant_partial() { entry: %output = alloca <4 x float>, align 16 br label %loop_begin loop_begin: ; preds = %skip, %entry br i1 undef, label %skip, label %0 0: ; preds = %loop_begin %1 = icmp uge <4 x i32> zeroinitializer, undef %2 = sext <4 x i1> %1 to <4 x i32> %3 = load i32, i32* undef, align 4 %4 = insertelement <4 x i32> undef, i32 %3, i32 3 %5 = trunc <4 x i32> %2 to <4 x i1> %6 = select <4 x i1> %5, <4 x i32> zeroinitializer, <4 x i32> %4 %7 = insertvalue [4 x <4 x i32>] undef, <4 x i32> %6, 0 %8 = insertvalue [4 x <4 x i32>] %7, <4 x i32> undef, 1 %9 = insertvalue [4 x <4 x i32>] %8, <4 x i32> undef, 2 %10 = insertvalue [4 x <4 x i32>] %9, <4 x i32> undef, 3 %11 = extractvalue [4 x <4 x i32>] %10, 0 %12 = bitcast <4 x i32> %11 to <4 x float> %13 = fmul <4 x float> zeroinitializer, %12 %14 = fadd <4 x float> %13, zeroinitializer %15 = fadd <4 x float> %14, zeroinitializer %16 = bitcast <4 x float> %15 to <4 x i32> %17 = insertvalue [4 x <4 x i32>] undef, <4 x i32> %16, 0 %18 = insertvalue [4 x <4 x i32>] %17, <4 x i32> undef, 1 %19 = insertvalue [4 x <4 x i32>] %18, <4 x i32> undef, 2 %20 = insertvalue [4 x <4 x i32>] %19, <4 x i32> undef, 3 %21 = extractvalue [4 x <4 x i32>] %20, 0 %22 = bitcast <4 x i32> %21 to <4 x float> store <4 x float> %22, <4 x float>* %output, align 16 br label %skip skip: ; preds = %0, %loop_begin br label %loop_begin } Crash is slightly different now: LLVM ERROR: Cannot select: t48: v4i32 = ARMISD::VCMPZ undef:v4i32, Constant:i32<2> t3: v4i32 = undef t47: i32 = Constant<2> This obviously corresponds to the %1 = icmp uge <4 x i32> zeroinitializer, undef With that knowledge we can reduce further: define <4 x i32> @fs_variant_partial() { %1 = icmp uge <4 x i32> zeroinitializer, undef %2 = sext <4 x i1> %1 to <4 x i32> ret <4 x i32> %2 } or define <4 x i32> @fs_variant_partial(<4 x i32> %0) { %2 = icmp uge <4 x i32> zeroinitializer, %0 %3 = sext <4 x i1> %2 to <4 x i32> ret <4 x i32> %3 } I'll see if I can spot where we're missing something, but likely I'll just file a bug and let the ARM people figure it where this should be fixed. From the looks of it we're simply not able to lower "icmp uge <4 x i32> zeroinitializer, ...", and the nested instructions have nothing to do with it. Reply at: https://bugs.launchpad.net/ubuntu/+source/llvm- toolchain-15/+bug/1993800/comments/8 ------------------------------------------------------------------------ On 2022-10-21T09:11:33+00:00 Fvogt-a wrote: The rabbit hole is deep! I noticed two oddities: The bitcode triggers the error in llc-{13,14,15}, so it's not a change in LLVM. I built Mesa 22.2.1 with LLVM14 (building old Mesa with LLVM15 does not work) and the bitcode produced also triggers the error in llc-{13, 14, 15}. I built Mesa 22.1.7 with LLVM14 as well and the bitcode also triggers the error! So the difference has to be somewhere in how Mesa invokes LLVM. I added LLVMPassBuilderOptionsSetDebugLogging(opts, true); to print the passes. Output with Mesa 22.2.1 + LLVM 15: ir_fs322_variant0.bc written Invoke as "opt -sroa -early-cse -simplifycfg -reassociate -mem2reg -constprop -instcombine -gvn ir_fs322_variant0.bc | llc -O2 [-mcpu=<-mcpu option>] [-mattr=<-mattr option(s)>]" Running pass: AlwaysInlinerPass on [module] Running analysis: InnerAnalysisManagerProxy<llvm::FunctionAnalysisManager, llvm::Module> on [module] Running analysis: ProfileSummaryAnalysis on [module] Running pass: CoroConditionalWrapper on [module] Running pass: AnnotationRemarksPass on fs_variant_partial (1387 instructions) Running analysis: TargetLibraryAnalysis on fs_variant_partial LLVM ERROR: Cannot select: 0x10505b0: v4i32 = ARMISD::VCMPZ 0x1287c98, Constant:i32<2> Mesa with LLVM 14 did not output that at all, which was caused by this conditional: #if LLVM_VERSION_MAJOR >= 15 #define GALLIVM_HAVE_CORO 0 #define GALLIVM_USE_NEW_PASS 1 #elif LLVM_VERSION_MAJOR >= 8 #define GALLIVM_HAVE_CORO 1 #define GALLIVM_USE_NEW_PASS 0 #else #define GALLIVM_HAVE_CORO 0 #define GALLIVM_USE_NEW_PASS 0 #endif So with LLVM >= 15 it uses the new pass manager and everything is different. Some experiments with opt + llc proved to be very helpful: opt -passes=always-inline,instcombine ir_fs322_variant0.bc | llc -mcpu=generic -> works opt -passes=always-inline ir_fs322_variant0.bc | llc -mcpu=generic -> fails! So the "instcombine" pass makes all the difference here to avoid the "Cannot select" error. Question is, why is the instcombine pass not used? Mesa hardcodes it in the list of passes after all: if (!(gallivm_perf & GALLIVM_PERF_NO_OPT)) strcpy(passes, "sroa,early-cse,simplifycfg,reassociate,mem2reg,constprop,instcombine,"); else strcpy(passes, "mem2reg"); LLVMRunPasses(gallivm->module, passes, LLVMGetExecutionEngineTargetMachine(gallivm->engine), opts); opt can actually answer that quickly: e06e5d2ccf7e:~/mesa/build # opt-15.0.2 -passes=sroa,early-cse,simplifycfg,reassociate,mem2reg,constprop,instcombine, ir_fs322_variant0.bc | llc-14.0.6 -mcpu=generic opt-15.0.2: unknown function pass 'constprop' (failure) Next try: e06e5d2ccf7e:~/mesa/build # opt-15.0.2 -passes=sroa,early-cse,simplifycfg,reassociate,mem2reg,instcombine, ir_fs322_variant0.bc | llc-14.0.6 -mcpu=generic opt-15.0.2: unknown function pass '' (failure) Next try: e06e5d2ccf7e:~/mesa/build # opt-15.0.2 -passes=sroa,early-cse,simplifycfg,reassociate,mem2reg,instcombine ir_fs322_variant0.bc | llc-14.0.6 -mcpu=generic .text .syntax unified (success!) So the missing "instcombine" pass causes the "Cannot select" error and the pass is missing because Mesa passes an invalid list of passes to LLVMRunPasses and ignores the error. This means that if Mesa was built with LLVM >= 15, only the "default<O2>" passes were actually run, so the code was not really optimized... With this patch, the "Cannot select" error is gone: if (!(gallivm_perf & GALLIVM_PERF_NO_OPT)) - strcpy(passes, "sroa,early-cse,simplifycfg,reassociate,mem2reg,constprop,instcombine,"); + strcpy(passes, "sroa,early-cse,simplifycfg,reassociate,mem2reg,instsimplify,instcombine"); else strcpy(passes, "mem2reg"); I'll send that to mesa upstream. Reply at: https://bugs.launchpad.net/ubuntu/+source/llvm- toolchain-15/+bug/1993800/comments/9 ** Changed in: llvm-toolchain-15 (openSUSE) Importance: Unknown => Medium -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to mesa in Ubuntu. https://bugs.launchpad.net/bugs/1993800 Title: LLVM ERROR: Cannot select: 0x2f689c8: v4i32 = ARMISD::VCMPZ 0x2f696b8, Constant:i32<2> Status in LLVM: Unknown Status in llvm-toolchain-15 package in Ubuntu: Confirmed Status in mesa package in Ubuntu: Confirmed Status in llvm-toolchain-15 package in openSUSE: Unknown Bug description: LLVM ERROR: Cannot select: 0x2f689c8: v4i32 = ARMISD::VCMPZ 0x2f696b8, Constant:i32<2> 0x2f696b8: v4i32,ch = ARMISD::VLD1DUP<(load (s32) from %ir.212)> 0x2aad434, 0x2f84090:1, Constant:i32<4> 0x2f84090: i32,i32,ch = load<(load (s32) from %ir.209, align 8), <post-inc>> 0x2aad434, 0x2f63a30, Constant:i32<64> 0x2f63a30: i32,ch = CopyFromReg 0x2aad434, Register:i32 %23 0x2f51c10: i32 = Register %23 0x2f82500: i32 = Constant<64> 0x2f81b28: i32 = Constant<4> 0x2f81e40: i32 = Constant<2> In function: fs_variant_partial [https://launchpadlibrarian.net/629171689/buildlog_ubuntu-kinetic- armhf.mutter_43.0-1ubuntu3_BUILDING.txt.gz] Although "LLVM ERROR: Cannot select" seems to be from LLVM, I can't determine what project "fs_variant_partial" is in. Sounds like it might be in some old version of Mesa? The start of the log suggests it's running on focal. To manage notifications about this bug go to: https://bugs.launchpad.net/llvm/+bug/1993800/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
