LLVM assertion error on release-0.6 while building docs

[vchuravy]

Travis is triggering an LLVM assertions on release-0.6 while building the docs: https://travis-ci.org/JuliaLang/julia/jobs/309198066

julia: /home/travis/build/JuliaLang/julia/deps/srccache/llvm-3.9.1/lib/IR/Instruction.cpp:30: llvm::Instruction::Instruction(llvm::Type*, unsigned int, llvm::Use*, unsigned int, llvm::Instruction*): Assertion `BB && "Instruction to insert before is not in a basic block!"' failed.
signal (6): Aborted
while loading /home/travis/build/JuliaLang/julia/doc/make.jl, in expression starting on line 5
gsignal at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)
abort at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)
unknown function (ip: 0x2b1b157f0bf5)
__assert_fail at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)
_ZN4llvm11InstructionC2EPNS_4TypeEjPNS_3UseEjPS0_ at /home/travis/build/JuliaLang/julia/usr/bin/../lib/libLLVM-3.9.so (unknown line)
_ZN4llvm8LoadInstC2EPNS_4TypeEPNS_5ValueERKNS_5TwineEbjNS_14AtomicOrderingENS_20SynchronizationScopeEPNS_11InstructionE at /home/travis/build/JuliaLang/julia/usr/bin/../lib/libLLVM-3.9.so (unknown line)
_ZN4llvm8LoadInstC1EPNS_4TypeEPNS_5ValueERKNS_5TwineEbjPNS_11InstructionE at /home/travis/build/JuliaLang/julia/usr/bin/../lib/libLLVM-3.9.so (unknown line)
unknown function (ip: 0x2b1b1674541f)
unknown function (ip: 0x2b1b16748d28)
_ZN4llvm15PromoteMemToRegENS_8ArrayRefIPNS_10AllocaInstEEERNS_13DominatorTreeEPNS_15AliasSetTrackerEPNS_15AssumptionCacheE at /home/travis/build/JuliaLang/julia/usr/bin/../lib/libLLVM-3.9.so (unknown line)
unknown function (ip: 0x2b1b16733bd8)
_ZN4llvm13FPPassManager13runOnFunctionERNS_8FunctionE at /home/travis/build/JuliaLang/julia/usr/bin/../lib/libLLVM-3.9.so (unknown line)
_ZN4llvm13FPPassManager11runOnModuleERNS_6ModuleE at /home/travis/build/JuliaLang/julia/usr/bin/../lib/libLLVM-3.9.so (unknown line)
_ZN4llvm6legacy15PassManagerImpl3runERNS_6ModuleE at /home/travis/build/JuliaLang/julia/usr/bin/../lib/libLLVM-3.9.so (unknown line)
operator() at /home/travis/build/JuliaLang/julia/src/jitlayers.cpp:460 [inlined]
_M_invoke at /usr/include/c++/5/functional:1857
operator() at /usr/include/c++/5/functional:2267 [inlined]
addModuleSet<llvm::SmallVector<std::unique_ptr<llvm::Module>, 1u>, llvm::RTDyldMemoryManager*, std::unique_ptr<llvm::orc::LambdaResolver<JuliaOJIT::addModule(std::unique_ptr<llvm::Module>)::<lambda(const string&)>, JuliaOJIT::addModule(std::unique_ptr<llvm::Module>)::<lambda(const string&)> >, std::default_delete<llvm::orc::LambdaResolver<JuliaOJIT::addModule(std::unique_ptr<llvm::Module>)::<lambda(const string&)>, JuliaOJIT::addModule(std::unique_ptr<llvm::Module>)::<lambda(const string&)> > > > > at /home/travis/build/JuliaLang/julia/usr/include/llvm/ExecutionEngine/Orc/IRCompileLayer.h:73 [inlined]
addModule at /home/travis/build/JuliaLang/julia/src/jitlayers.cpp:587
jl_add_to_ee at /home/travis/build/JuliaLang/julia/src/jitlayers.cpp:810 [inlined]
jl_finalize_function at /home/travis/build/JuliaLang/julia/src/jitlayers.cpp:821
getAddressForFunction at /home/travis/build/JuliaLang/julia/src/codegen.cpp:1411
jl_generate_fptr at /home/travis/build/JuliaLang/julia/src/codegen.cpp:1508
jl_compile_method_internal at /home/travis/build/JuliaLang/julia/src/julia_internal.h:326 [inlined]
jl_call_method_internal at /home/travis/build/JuliaLang/julia/src/julia_internal.h:354 [inlined]
jl_apply_generic at /home/travis/build/JuliaLang/julia/src/gf.c:1926
#cd#1 at ./pkg/dir.jl:32
jl_call_fptr_internal at /home/travis/build/JuliaLang/julia/src/julia_internal.h:339 [inlined]
jl_call_method_internal at /home/travis/build/JuliaLang/julia/src/julia_internal.h:358 [inlined]
jl_apply_generic at /home/travis/build/JuliaLang/julia/src/gf.c:1926
jl_apply at /home/travis/build/JuliaLang/julia/src/julia.h:1424 [inlined]
jl_invoke at /home/travis/build/JuliaLang/julia/src/gf.c:51
update at ./pkg/pkg.jl:228
jl_call_fptr_internal at /home/travis/build/JuliaLang/julia/src/julia_internal.h:339 [inlined]
jl_call_method_internal at /home/travis/build/JuliaLang/julia/src/julia_internal.h:358 [inlined]
jl_apply_generic at /home/travis/build/JuliaLang/julia/src/gf.c:1926
do_call at /home/travis/build/JuliaLang/julia/src/interpreter.c:75
eval at /home/travis/build/JuliaLang/julia/src/interpreter.c:242
jl_interpret_toplevel_expr at /home/travis/build/JuliaLang/julia/src/interpreter.c:34
jl_toplevel_eval_flex at /home/travis/build/JuliaLang/julia/src/toplevel.c:577
jl_parse_eval_all at /home/travis/build/JuliaLang/julia/src/ast.c:873
jl_load at /home/travis/build/JuliaLang/julia/src/toplevel.c:616
include_from_node1 at ./loading.jl:576
unknown function (ip: 0x2b1b19c916bb)
jl_call_fptr_internal at /home/travis/build/JuliaLang/julia/src/julia_internal.h:339 [inlined]
jl_call_method_internal at /home/travis/build/JuliaLang/julia/src/julia_internal.h:358 [inlined]
jl_apply_generic at /home/travis/build/JuliaLang/julia/src/gf.c:1926
include at ./sysimg.jl:14
unknown function (ip: 0x2b1b19b2394b)
jl_call_fptr_internal at /home/travis/build/JuliaLang/julia/src/julia_internal.h:339 [inlined]
jl_call_method_internal at /home/travis/build/JuliaLang/julia/src/julia_internal.h:358 [inlined]
jl_apply_generic at /home/travis/build/JuliaLang/julia/src/gf.c:1926
process_options at ./client.jl:305
_start at ./client.jl:371
unknown function (ip: 0x2b1b19ca04b8)
jl_call_fptr_internal at /home/travis/build/JuliaLang/julia/src/julia_internal.h:339 [inlined]
jl_call_method_internal at /home/travis/build/JuliaLang/julia/src/julia_internal.h:358 [inlined]
jl_apply_generic at /home/travis/build/JuliaLang/julia/src/gf.c:1926
jl_apply at /home/travis/build/JuliaLang/julia/ui/../src/julia.h:1424 [inlined]
true_main at /home/travis/build/JuliaLang/julia/ui/repl.c:127
main at /home/travis/build/JuliaLang/julia/ui/repl.c:264
__libc_start_main at /lib/x86_64-linux-gnu/libc.so.6 (unknown line)
unknown function (ip: 0x40160e)
Allocations: 6081730 (Pool: 6080128; Big: 1602); GC: 11
make[2]: *** [html] Aborted (core dumped)
263.939448 make[2]: Leaving directory `/home/travis/build/JuliaLang/julia/doc'
make[1]: *** [docs] Error 2
make: *** [/home/travis/build/JuliaLang/julia/doc/_build/html/en/index.html] Error 2
263.939900 make[1]: Leaving directory `/home/travis/build/JuliaLang/julia

I haven't managed to reproduce that locally. cc: @ararslan

[vtjnash]

Possibly caused by

julia/src/cgutils.cpp

Lines 2092 to 2093 in 3835d80

	if (skip) // copy dest -> dest to simulate an undef value / conditional copy
	src_ptr = builder.CreateSelect(skip, dest, src_ptr);

This code is intended to trigger runtime UB, but according to Keno, it also triggers LLVM bugs, so on master, he replaced it with a large performance regression (https://github.com/JuliaLang/julia/blame/c1cf539c6cf6915f2870fcddbbe7aeb47a0e11ba/src/cgutils.cpp#L2214 - the comment on that line is wrong now btw).

[ararslan]

I can't reproduce with a stock build nor with a build with these options:

LLVM_DEBUG=1
LLVM_ASSERTIONS=1
FORCE_ASSERTIONS=1

But it happens on every Travis Linux build on release-0.6. :/

[ararslan]

I assume this is blocking the release of 0.6.2, so any help would be much appreciated.

[vtjnash]

Did the release-0.6 branch get any patches applied to lllvm in the cache at some point? Maybe reset that and try again?

[ararslan]

I'm not sure how to do that. Do you have any pointers, @vtjnash?

[vtjnash]

Just click the trash can icon https://travis-ci.org/JuliaLang/julia/caches

[ararslan]

It looks like I don't have the necessary permissions to do that.

[Keno]

@ararslan should be tied to the commit bit, are you signed in on Travis?

[ararslan]

Ah yeah, I was getting confused by redirects. I've deleted the cache and restarted the most recent build on release-0.6, so we'll see what happens.

[ararslan]

Seems not to have helped: https://travis-ci.org/JuliaLang/julia/builds/309339079. Same error.

[maleadt]

Had a quick look with the archive @ararslan put on anubis. A better backtrace:

INFO: Initializing package repository doc/deps/v0.6
INFO: Package directory doc/deps/v0.6 is already initialized.
julia: deps/srccache/llvm-3.9.1/lib/IR/Instruction.cpp:30: llvm::Instruction::Instruction(llvm::Type*, unsigned int, llvm::Use*, unsigned int, llvm::Instruction*): Assertion `BB && "Instruction to insert before is not in a basic block!"' failed.

Thread 1 "julia" received signal SIGABRT, Aborted.
__GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:58
58      ../sysdeps/unix/sysv/linux/raise.c: No such file or directory.
(gdb) bt
#0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:58
#1  0x00007ffff6ce83ea in __GI_abort () at abort.c:89
#2  0x00007ffff6cdebb7 in __assert_fail_base (fmt=<optimized out>, assertion=assertion@entry=0x7ffff5d32b20 "BB && \"Instruction to insert before is not in a basic block!\"", 
    file=file@entry=0x7ffff5d32a90 "deps/srccache/llvm-3.9.1/lib/IR/Instruction.cpp", line=line@entry=30, 
    function=function@entry=0x7ffff5d36720 <llvm::Instruction::Instruction(llvm::Type*, unsigned int, llvm::Use*, unsigned int, llvm::Instruction*)::__PRETTY_FUNCTION__> "llvm::Instruction::Instruction(llvm::Type*, unsigned int, llvm::Use*, unsigned int, llvm::Instruction*)") at assert.c:92
#3  0x00007ffff6cdec62 in __GI___assert_fail (assertion=0x7ffff5d32b20 "BB && \"Instruction to insert before is not in a basic block!\"", 
    file=0x7ffff5d32a90 "deps/srccache/llvm-3.9.1/lib/IR/Instruction.cpp", line=30, 
    function=0x7ffff5d36720 <llvm::Instruction::Instruction(llvm::Type*, unsigned int, llvm::Use*, unsigned int, llvm::Instruction*)::__PRETTY_FUNCTION__> "llvm::Instruction::Instruction(llvm::Type*, unsigned int, llvm::Use*, unsigned int, llvm::Instruction*)") at assert.c:101
#4  0x00007ffff4bec454 in llvm::Instruction::Instruction(llvm::Type*, unsigned int, llvm::Use*, unsigned int, llvm::Instruction*) () from usr/bin/../lib/libLLVM-3.9.so
#5  0x00007ffff4bf809d in llvm::LoadInst::LoadInst(llvm::Type*, llvm::Value*, llvm::Twine const&, bool, unsigned int, llvm::AtomicOrdering, llvm::SynchronizationScope, llvm::Instruction*) ()
   from usr/bin/../lib/libLLVM-3.9.so
#6  0x00007ffff4bf81e5 in llvm::LoadInst::LoadInst(llvm::Type*, llvm::Value*, llvm::Twine const&, bool, unsigned int, llvm::Instruction*) () from usr/bin/../lib/libLLVM-3.9.so
#7  0x00007ffff5284420 in doMemCpySplit((anonymous namespace)::LargeBlockInfo&, llvm::MemCpyInst*, llvm::AllocaInst*) [clone .constprop.437] () from usr/bin/../lib/libLLVM-3.9.so
#8  0x00007ffff5287d29 in (anonymous namespace)::PromoteMem2Reg::run() [clone .constprop.419] () from usr/bin/../lib/libLLVM-3.9.so
#9  0x00007ffff528a012 in llvm::PromoteMemToReg(llvm::ArrayRef<llvm::AllocaInst*>, llvm::DominatorTree&, llvm::AliasSetTracker*, llvm::AssumptionCache*) () from usr/bin/../lib/libLLVM-3.9.so
#10 0x00007ffff5272bd9 in promoteMemoryToRegister(llvm::Function&, llvm::DominatorTree&, llvm::AssumptionCache&) [clone .constprop.79] () from usr/bin/../lib/libLLVM-3.9.so
#11 0x00007ffff4c1cfc3 in llvm::FPPassManager::runOnFunction(llvm::Function&) () from usr/bin/../lib/libLLVM-3.9.so
#12 0x00007ffff4c1d35b in llvm::FPPassManager::runOnModule(llvm::Module&) () from usr/bin/../lib/libLLVM-3.9.so
#13 0x00007ffff4c1cb5a in llvm::legacy::PassManagerImpl::run(llvm::Module&) () from usr/bin/../lib/libLLVM-3.9.so
#14 0x00007ffff7798dce in JuliaOJIT::<lambda(llvm::Module&)>::operator() (M=..., __closure=0x70a508) at src/jitlayers.cpp:460
#15 std::_Function_handler<llvm::object::OwningBinary<llvm::object::ObjectFile>(llvm::Module&), JuliaOJIT::JuliaOJIT(llvm::TargetMachine&)::<lambda(llvm::Module&)> >::_M_invoke(const std::_Any_data &, llvm::Module &) (__functor=..., 
    __args#0=...) at /usr/include/c++/5/functional:1857
#16 0x00007ffff779b879 in std::function<llvm::object::OwningBinary<llvm::object::ObjectFile> (llvm::Module&)>::operator()(llvm::Module&) const (__args#0=..., this=<optimized out>) at /usr/include/c++/5/functional:2267
#17 llvm::orc::IRCompileLayer<llvm::orc::ObjectLinkingLayer<JuliaOJIT::DebugObjectRegistrar> >::addModuleSet<llvm::SmallVector<std::unique_ptr<llvm::Module>, 1u>, llvm::RTDyldMemoryManager*, std::unique_ptr<llvm::orc::LambdaResolver<JuliaOJIT::addModule(std::unique_ptr<llvm::Module>)::<lambda(const string&)>, JuliaOJIT::addModule(std::unique_ptr<llvm::Module>)::<lambda(const string&)> >, std::default_delete<llvm::orc::LambdaResolver<JuliaOJIT::addModule(std::unique_ptr<llvm::Module>)::<lambda(const string&)>, JuliaOJIT::addModule(std::unique_ptr<llvm::Module>)::<lambda(const string&)> > > > > (Resolver=..., MemMgr=0x717300, Ms=..., this=<optimized out>)
    at usr/include/llvm/ExecutionEngine/Orc/IRCompileLayer.h:73
#18 JuliaOJIT::addModule (this=<optimized out>, M=std::unique_ptr<llvm::Module> containing 0x0) at src/jitlayers.cpp:587
#19 0x00007ffff779c4ee in jl_add_to_ee (m=...) at src/jitlayers.cpp:810
#20 jl_finalize_function (F=F@entry=0x275d298) at src/jitlayers.cpp:821
#21 0x00007ffff774be73 in getAddressForFunction (llvmf=llvmf@entry=0x275d298) at src/codegen.cpp:1411
#22 0x00007ffff7795dfa in jl_generate_fptr (li=0x7fffbae2a290, _F=<optimized out>, world=world@entry=21833) at src/codegen.cpp:1508
#23 0x00007ffff76df4f8 in jl_compile_method_internal (meth=0x7fffbae2a290, fptr=<synthetic pointer>) at src/julia_internal.h:326
#24 jl_call_method_internal (nargs=3, args=0x7fffffffcbc8, meth=<optimized out>) at src/julia_internal.h:354
#25 jl_apply_generic (args=0x7fffffffcbc8, nargs=<optimized out>) at src/gf.c:1926
#26 0x00007fffbee94cc3 in japi1_#cd#1_62782 () at pkg/dir.jl:32
#27 0x00007ffff76df527 in jl_call_fptr_internal (fptr=<synthetic pointer>, fptr=<synthetic pointer>, nargs=6, args=0x7fffffffcd98, meth=<optimized out>) at src/julia_internal.h:339
#28 jl_call_method_internal (nargs=6, args=0x7fffffffcd98, meth=<optimized out>) at src/julia_internal.h:358
#29 jl_apply_generic (args=args@entry=0x7fffffffcd98, nargs=nargs@entry=6) at src/gf.c:1926
#30 0x00007ffff76df6f7 in jl_apply (nargs=6, args=0x7fffffffcd98) at src/julia.h:1424
#31 jl_invoke (meth=<optimized out>, args=0x7fffffffcd98, nargs=6) at src/gf.c:51
#32 0x00007fffbee93fdf in japi1_update_62776 () at pkg/pkg.jl:228
#33 0x00007ffff76df527 in jl_call_fptr_internal (fptr=<synthetic pointer>, fptr=<synthetic pointer>, nargs=1, args=0x7fffffffcee0, meth=<optimized out>) at src/julia_internal.h:339
#34 jl_call_method_internal (nargs=1, args=0x7fffffffcee0, meth=<optimized out>) at src/julia_internal.h:358
#35 jl_apply_generic (args=args@entry=0x7fffffffcee0, nargs=nargs@entry=1) at src/gf.c:1926
#36 0x00007ffff76f599e in do_call (args=args@entry=0x7fffbafafc50, nargs=nargs@entry=1, s=s@entry=0x0) at src/interpreter.c:75
#37 0x00007ffff76f4663 in eval (e=e@entry=0x7fffbafb5150, s=s@entry=0x0) at src/interpreter.c:242
#38 0x00007ffff76f58d4 in jl_interpret_toplevel_expr (e=0x7fffbafb5150) at src/interpreter.c:34
#39 0x00007ffff770f737 in jl_toplevel_eval_flex (e=<optimized out>, fast=fast@entry=1, expanded=expanded@entry=1) at src/toplevel.c:577
#40 0x00007ffff76e9917 in jl_parse_eval_all (fname=fname@entry=0x7ffff00b2fe8 "doc/make.jl", content=content@entry=0x0, contentlen=contentlen@entry=0) at src/ast.c:873
#41 0x00007ffff770fd74 in jl_load (fname=0x7ffff00b2fe8 "doc/make.jl") at src/toplevel.c:616
#42 0x00007ffff11989d6 in julia_include_from_node1_18743 () at loading.jl:576
#43 0x00007ffff1198bac in jlcall_include_from_node1_18742 () from usr/lib/julia/sys.so
#44 0x00007ffff76df527 in jl_call_fptr_internal (fptr=<synthetic pointer>, fptr=<synthetic pointer>, nargs=2, args=0x7fffffffdad8, meth=<optimized out>) at src/julia_internal.h:339
#45 jl_call_method_internal (nargs=2, args=0x7fffffffdad8, meth=<optimized out>) at src/julia_internal.h:358
#46 jl_apply_generic (args=0x7fffffffdad8, nargs=<optimized out>) at src/gf.c:1926
#47 0x00007ffff1030c40 in julia_include_1023 () at sysimg.jl:14
#48 0x00007ffff1030cac in jlcall_include_1022 () from usr/lib/julia/sys.so
---Type <return> to continue, or q <return> to quit---
#49 0x00007ffff76df527 in jl_call_fptr_internal (fptr=<synthetic pointer>, fptr=<synthetic pointer>, nargs=2, args=0x7fffffffdcc0, meth=<optimized out>) at src/julia_internal.h:339
#50 jl_call_method_internal (nargs=2, args=0x7fffffffdcc0, meth=<optimized out>) at src/julia_internal.h:358
#51 jl_apply_generic (args=0x7fffffffdcc0, nargs=<optimized out>) at src/gf.c:1926
#52 0x00007ffff11a4587 in julia_process_options_18989 () at client.jl:305
#53 0x00007ffff11a6bab in julia__start_18982 () at client.jl:371
#54 0x00007ffff11a75f9 in jlcall.start_18981 () from usr/lib/julia/sys.so
#55 0x00007ffff76df527 in jl_call_fptr_internal (fptr=<synthetic pointer>, fptr=<synthetic pointer>, nargs=1, args=0x7fffffffe1f0, meth=<optimized out>) at src/julia_internal.h:339
#56 jl_call_method_internal (nargs=1, args=0x7fffffffe1f0, meth=<optimized out>) at src/julia_internal.h:358
#57 jl_apply_generic (args=args@entry=0x7fffffffe1f0, nargs=nargs@entry=1) at src/gf.c:1926
#58 0x0000000000401d52 in jl_apply (nargs=1, args=0x7fffffffe1f0) at ui/../src/julia.h:1424
#59 true_main (argc=<optimized out>, argv=0x7fffffffe560) at ui/repl.c:127
#60 0x0000000000401563 in main (argc=1, argv=0x7fffffffe560) at ui/repl.c:264

However, lacking julia-debug it's pretty anoying to debug. I managed to capture the IR submitted to the JIT: https://file.io/TvBSgZ (warning: 10MB IR), but haven't managed to reproduce the crash with opt. Somebody have an opt invocation mimicking our pass manager laying around?

EDIT: OK, managed to get a hold of the function that makes mem2reg crash (doing a manual call _ZN4llvm2cl23ParseEnvironmentOptionsEPKcS2_S2_("Julia", "JULIA_LLVM_ARGS") from jl_init_llvm): https://file.io/Trz3ul, run with opt -mem2reg.

[maleadt]

MWE after bugpoint:

; ModuleID = 'bugpoint-reduced-simplified.bc'
source_filename = "bugpoint-output-59d46bf.bc"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: argmemonly nounwind
declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture writeonly, i8* nocapture readonly, i32, i32, i1) #0

define void @julia_push() {
top:
  %item = alloca i8
  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %item, i8* %item, i32 1, i32 1, i1 false)
  unreachable
}

attributes #0 = { argmemonly nounwind }

$ ./usr/tools/opt -mem2reg bugpoint-reduced-simplified.ll
opt: /home/travis/build/JuliaLang/julia/deps/srccache/llvm-3.9.1/lib/IR/Instruction.cpp:30: llvm::Instruction::Instruction(llvm::Type*, unsigned int, llvm::Use*, unsigned int, llvm::Instruction*): Assertion `BB && "Instruction to insert before is not in a basic block!"' failed.
#0 0x00007f8b9365a935 llvm::sys::PrintStackTrace(llvm::raw_ostream&) (usr/tools/../lib/libLLVM-3.9.so+0x47a935)
#1 0x00007f8b936587de llvm::sys::RunSignalHandlers() (usr/tools/../lib/libLLVM-3.9.so+0x4787de)
#2 0x00007f8b93658942 SignalHandler(int) (usr/tools/../lib/libLLVM-3.9.so+0x478942)
#3 0x00007f8b92ac6860 (/lib/x86_64-linux-gnu/libc.so.6+0x35860)
#4 0x00007f8b92ac67ef gsignal /build/glibc-MECilU/glibc-2.24/signal/../sysdeps/unix/sysv/linux/raise.c:58:0
#5 0x00007f8b92ac83ea abort /build/glibc-MECilU/glibc-2.24/stdlib/abort.c:91:0
#6 0x00007f8b92abebb7 __assert_fail_base /build/glibc-MECilU/glibc-2.24/assert/assert.c:92:0
#7 0x00007f8b92abec62 (/lib/x86_64-linux-gnu/libc.so.6+0x2dc62)
#8 0x00007f8b93703454 llvm::Instruction::Instruction(llvm::Type*, unsigned int, llvm::Use*, unsigned int, llvm::Instruction*) (usr/tools/../lib/libLLVM-3.9.so+0x523454)
#9 0x00007f8b9370f09d llvm::LoadInst::LoadInst(llvm::Type*, llvm::Value*, llvm::Twine const&, bool, unsigned int, llvm::AtomicOrdering, llvm::SynchronizationScope, llvm::Instruction*) (usr/tools/../lib/libLLVM-3.9.so+0x52f09d)
#10 0x00007f8b9370f1e5 llvm::LoadInst::LoadInst(llvm::Type*, llvm::Value*, llvm::Twine const&, bool, unsigned int, llvm::Instruction*) (usr/tools/../lib/libLLVM-3.9.so+0x52f1e5)
#11 0x00007f8b93d9b420 doMemCpySplit((anonymous namespace)::LargeBlockInfo&, llvm::MemCpyInst*, llvm::AllocaInst*) [clone .constprop.437] (usr/tools/../lib/libLLVM-3.9.so+0xbbb420)
#12 0x00007f8b93d9ed29 (anonymous namespace)::PromoteMem2Reg::run() [clone .constprop.419] (usr/tools/../lib/libLLVM-3.9.so+0xbbed29)
#13 0x00007f8b93da1012 llvm::PromoteMemToReg(llvm::ArrayRef<llvm::AllocaInst*>, llvm::DominatorTree&, llvm::AliasSetTracker*, llvm::AssumptionCache*) (usr/tools/../lib/libLLVM-3.9.so+0xbc1012)
#14 0x00007f8b93d89bd9 promoteMemoryToRegister(llvm::Function&, llvm::DominatorTree&, llvm::AssumptionCache&) [clone .constprop.79] (usr/tools/../lib/libLLVM-3.9.so+0xba9bd9)
#15 0x00007f8b93733fc3 llvm::FPPassManager::runOnFunction(llvm::Function&) (usr/tools/../lib/libLLVM-3.9.so+0x553fc3)
#16 0x00007f8b9373435b llvm::FPPassManager::runOnModule(llvm::Module&) (usr/tools/../lib/libLLVM-3.9.so+0x55435b)
#17 0x00007f8b93733b5a llvm::legacy::PassManagerImpl::run(llvm::Module&) (usr/tools/../lib/libLLVM-3.9.so+0x553b5a)
#18 0x000000000041425f main (./usr/tools/opt+0x41425f)
#19 0x00007f8b92ab13f1 __libc_start_main /build/glibc-MECilU/glibc-2.24/csu/../csu/libc-start.c:325:0
#20 0x0000000000414acb _start (./usr/tools/opt+0x414acb)

Strangely only crashes on a build from master on my system; Travis cache issue?