armv7l SIMD errors

[staticfloat]

Buildbots are showing the following:

Error in testset vecelement:
Error During Test at /buildworker/worker/package_linuxarmv7l/build/test/vecelement.jl:39
  Test threw an exception of type StackOverflowError
  Expression: unpeel(Bunch{2, Float64}((Base.VecElement(5.0), Base.VecElement(4.0)))) === 5.0
  StackOverflowError:
Error in testset vecelement:
Error During Test at /buildworker/worker/package_linuxarmv7l/build/test/testdefs.jl:19
  Got an exception of type LoadError outside of a @test
  LoadError: StackOverflowError:
  in expression starting at /buildworker/worker/package_linuxarmv7l/build/test/vecelement.jl:60

@yuyichao

[yuyichao]

This is just #21918

[staticfloat]

That issue says it's fixed; this issue is happening on current master.

[yuyichao]

It's basically only fixed for x86 but the alignment is still wrong on arm. I know it's closed which is why I didn't close as dup even though it is a dup...

[yuyichao]

Also, iirc, the misaligned load/store happens on sret slot so it's a segfault on stack and therefore being detectetd as a stackoverflow.

[staticfloat]

Just checking in to say that armv7l has been fixed enough for this issue to be the breaking point again. @yuyichao can you help us track down what the proper fix might be? Do we just need to change an alignment value somewhere?

Example failing test run is here, with the relevant portion copied out:

Worker 3 failed running test vecelement:
Some tests did not pass: 382 passed, 0 failed, 2 errored, 0 broken.vecelement: Error During Test at /buildworker/worker/tester_linuxarmv7l/build/share/julia/test/vecelement.jl:39
  Test threw exception
  Expression: unpeel(Bunch{2, Float64}((Base.VecElement(5.0), Base.VecElement(4.0)))) === 5.0
  StackOverflowError:
  
vecelement: Error During Test at /buildworker/worker/tester_linuxarmv7l/build/share/julia/test/testdefs.jl:20
  Got exception outside of a @test
  LoadError: StackOverflowError:
  Stacktrace:
   [1] Main.Test22Main_vecelement.Herd{4,Int32}(::NTuple{4,Int32}) at ./ntuple.jl:18
   [2] top-level scope at /buildworker/worker/tester_linuxarmv7l/build/share/julia/test/vecelement.jl:60
   [3] include at ./boot.jl:328 [inlined]
   [4] include_relative(::Module, ::String) at ./loading.jl:1094
   [5] include at ./Base.jl:31 [inlined]
   [6] include(::String) at /buildworker/worker/tester_linuxarmv7l/build/share/julia/test/testdefs.jl:13
   [7] top-level scope at /buildworker/worker/tester_linuxarmv7l/build/share/julia/test/testdefs.jl:23
   [8] top-level scope at /buildworker/worker/package_linuxarmv7l/build/usr/share/julia/stdlib/v1.3/Test/src/Test.jl:1113
   [9] top-level scope at /buildworker/worker/tester_linuxarmv7l/build/share/julia/test/testdefs.jl:22
   [10] top-level scope at util.jl:289
   [11] top-level scope at /buildworker/worker/tester_linuxarmv7l/build/share/julia/test/testdefs.jl:20
   [12] eval at ./boot.jl:330 [inlined]
   [13] #runtests#3(::UInt128, ::typeof(runtests), ::String, ::String, ::Bool) at /buildworker/worker/tester_linuxarmv7l/build/share/julia/test/testdefs.jl:26
   [14] #runtests at ./none:0 [inlined] (repeats 2 times)
   [15] (::getfield(Distributed, Symbol("##112#114")){Distributed.CallMsg{:call_fetch}})() at /buildworker/worker/package_linuxarmv7l/build/usr/share/julia/stdlib/v1.3/Distributed/src/process_messages.jl:294
   [16] run_work_thunk(::getfield(Distributed, Symbol("##112#114")){Distributed.CallMsg{:call_fetch}}, ::Bool) at /buildworker/worker/package_linuxarmv7l/build/usr/share/julia/stdlib/v1.3/Distributed/src/process_messages.jl:79
   [17] macro expansion at /buildworker/worker/package_linuxarmv7l/build/usr/share/julia/stdlib/v1.3/Distributed/src/process_messages.jl:294 [inlined]
   [18] (::getfield(Distributed, Symbol("##111#113")){Distributed.CallMsg{:call_fetch},Distributed.MsgHeader,Sockets.TCPSocket})() at ./task.jl:270
  in expression starting at /buildworker/worker/tester_linuxarmv7l/build/share/julia/test/vecelement.jl:60

[vtjnash]

That looks likely to be #21959