<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/71183>71183</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Memcpyopt crashes with simple IR
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          gbaraldi
      </td>
    </tr>
</table>

<pre>
    ```llvm-ir
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128-ni:10:11:12:13"
target triple = "x86_64-unknown-linux-gnu"

define void @"julia_#36#f_439"() {
top:
  call void @llvm.memcpy.p0.p11.i64(ptr null, ptr addrspace(11) null, i64 0, i1 false), !tbaa !0
  ret void
}

; Function Attrs: nocallback nofree nounwind willreturn memory(argmem: readwrite)
declare void @llvm.memcpy.p0.p11.i64(ptr noalias nocapture writeonly, ptr addrspace(11) noalias nocapture readonly, i64, i1 immarg) #0

attributes #0 = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }

!0 = !{!1, !1, i64 0, i64 1}
!1 = !{!"jtbaa_const", !2, i64 0}
!2 = !{!"jtbaa", !3, i64 0}
!3 = !{!"jtbaa"}
```
```c
opt: /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/include/llvm/Support/Casting.h:663: decltype(auto) llvm::dyn_cast(From*) [with To = llvm::MemoryUse; From = const llvm::MemoryUseOrDef]: Assertion `detail::isPresent(Val) && "dyn_cast on a non-existent value"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: ./opt reduced.ll --passes=memcpyopt -S
 #0 0x00007ff07cfaf7d4 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/lib/Support/Unix/Signals.inc:567:22
 #1 0x00007ff07cfafbaa PrintStackTraceSignalHandler(void*) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/lib/Support/Unix/Signals.inc:641:1
 #2 0x00007ff07cfad3c7 llvm::sys::RunSignalHandlers() /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/lib/Support/Signals.cpp:104:20
 #3 0x00007ff07cfaf0ec SignalHandler(int) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/lib/Support/Unix/Signals.inc:412:1
 #4 0x00007ff07ba42520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #5 0x00007ff07ba969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #6 0x00007ff07ba42476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #7 0x00007ff07ba287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #8 0x00007ff07ba2871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #9 0x00007ff07ba39e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
#10 0x00007ff07d6f1599 decltype(auto) llvm::dyn_cast<llvm::MemoryUse, llvm::MemoryUseOrDef const>(llvm::MemoryUseOrDef const*) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/include/llvm/Support/Casting.h:664:48
#11 0x00007ff07d6f1619 llvm::OperandTraits<llvm::MemoryUseOrDef>::operands(llvm::MemoryUseOrDef const*) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/include/llvm/Analysis/MemorySSA.h:440:45
#12 0x00007ff07d6f1669 llvm::MemoryUseOrDef::getOperand(unsigned int) const /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/include/llvm/Analysis/MemorySSA.h:445:1
#13 0x00007ff07d6f12af llvm::MemoryUseOrDef::getDefiningAccess() const /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/include/llvm/Analysis/MemorySSA.h:262:67
#14 0x00007ff07eed4ac7 llvm::MemCpyOptPass::processMemCpy(llvm::MemCpyInst*, llvm::ilist_iterator<llvm::ilist_detail::node_options<llvm::Instruction, true, false, void>, false, false>&) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp:1481:51
#15 0x00007ff07eed5bb8 llvm::MemCpyOptPass::iterateOnFunction(llvm::Function&) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp:1672:42
#16 0x00007ff07eed5fae llvm::MemCpyOptPass::runImpl(llvm::Function&, llvm::TargetLibraryInfo*, llvm::AAResults*, llvm::AssumptionCache*, llvm::DominatorTree*, llvm::MemorySSA*) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp:1723:9
#17 0x00007ff07eed5e29 llvm::MemCpyOptPass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/lib/Transforms/Scalar/MemCpyOptimizer.cpp:1700:28
#18 0x00007ff081b656e5 llvm::detail::PassModel<llvm::Function, llvm::MemCpyOptPass, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/include/llvm/IR/PassManagerInternal.h:90:3
#19 0x00007ff07d35c5c5 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/include/llvm/IR/PassManager.h:521:32
#20 0x00007ff080a86983 llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/include/llvm/IR/PassManagerInternal.h:90:3
#21 0x00007ff07d35b85a llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/lib/IR/PassManager.cpp:125:22
#22 0x00007ff080a868b3 llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::PreservedAnalyses, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/include/llvm/IR/PassManagerInternal.h:90:3
#23 0x00007ff07d35c281 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/include/llvm/IR/PassManager.h:521:32
#24 0x0000556a90e6bd9a llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::PassPlugin>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool) /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/tools/opt/NewPMDriver.cpp:518:10
#25 0x0000556a90e9d2d8 main /home/gabrielbaraldi/julia3/deps/srccache/llvm-julia-16.0.6-0/llvm/tools/opt/opt.cpp:719:27
#26 0x00007ff07ba29d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#27 0x00007ff07ba29e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#28 0x0000556a90e64b05 _start (./opt+0x1db05)
```
It seems memcpyop does `MSSA->getMemoryAccess(M)` which returns a null pointer which isn't guarded.
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzsWl9v2zgS_zTMC2FDov4_5MFJalxwm2vQZPfVoMSxzS1FCiTVxPfpD6SkWFKcNtk2aA-7ReHIJGc485u_pEyN4TsJcI6SC5RcndHW7pU-35VUU8H4WanY4RylQfdfiC_1gmsUXKFgZanegcWMWiroQbUWo-gKI0JgUaNoBYuGZAGKVhHxH-5rOP3qntLYfyz48LDNHVFI8oXM3UM60KTx4s4PczfsF4V-pfuIECETsazmjYBBpMc83aTxopWfpXqQC8Fl-7jYyfaJqvtksOUS8BfFGUZxgAj5sxWcbhCJohSRaLuJo8LRkByRAqPsot9TNSjqeWBcUSGeeDjIljXUVXNYNsGyCcOlU5XkjdVYtkIgcondM2VMm4ZWgEgeho79MMvTGAf-IcRbKgwgUriviIS2pNT9DYa9NVi_da9VdjVWD0UXeN3KynIl8cpabVC0wlI5gUtafcZSbTUAlqqVD1wy_MCF0GBbLXENtdIHRHKqdzU4A2MNlD1obr08PX6VoBpeqbyiglPj929sqwF7ZkqKw1cweUbkpBhoPHOPE69rqnfeSCQKxiBQazUvWwvGT3Uekl38GBjwHHES9juQ0HkLcVp4y4VTy6YxDo-0JAynVM4Tna03lZLGeg_0XMiRy4iYnCY-kkUnyaKXyZ5WDZlg9rXqvqvGOkQQWe9VDYisd7TUHESfTRBZ-3iKEFkzaAwia6OrilZ7t9YnFz-_CNNlsEwXQT-KyJrLSrQMjgN3bdMobRFZX1Jjudwt9y5HpJETwPmhPTTObWhrlTOMJ4tWKFqxg9xU1KGYr7WqEVl5wyUXD9zu8b3yKByX33iL_27AR49WtZ_3dji16qO-gi1KrpwYK2NA-2BDacDAUi661dzcajAgnQx_UNG5aYpI6nLVIB9WElMslVzAIzcWpMVfqGjBmzHDW8oFsGUH_O1vH1Z3H7Bpy5pbTHHZ7rAGBxC2Cu-tbVyoI7J2NuF235bLyqk-oOmxb7T6EyoHKTemBWceTCXDPfbY7gFXmpo9dlFiNa2g3_7OurBhbX1Mg8ES-3-3Wu00rTHVu7YGaX3KWSKyVo3FGlhbAVsKgReLhhoDBkVXXcJw84u7Pq_5SA0egyAIsu02yKot3WYsHhnAHEz3cKu5tF6ge91ljuMiTR82ylgNtPZ4X2LubFC8h8cKXk7c9HfJH90A30kqzJLLCkWrJM1QtBqKkFMznKvpMvxMp47Hv6hkAjQiuU_4vRv_JEXS2Nfiox5kpgeLquyUuT61cqKOGWrr-ysyaFA1je8oXANCgqMK0dwUAVR4jv1PdqC4a3-OQsdjoUsak4QE2GPaM-xboVEL5CaqpVHLFJGL4NGTPJV0xzOZ8izSYlvhxu5d5dt85kK8bQNPP9kgnQsdZyneGa_pW4WPs3TCO5vyJnm2jTAtXWp8E2dPOOGcP-Mclm_mGZYTnsWUZ1RAkb6Npyd54ukyyiRzsnQbJkXxyhIZXZ4qhOTyxcrXFUYUfZjk3ZNr3i1hvbpXcAEf50egwjlQaThG5WMDmkp2ryl3ZewUNF31jz50w6ojML8SFitJxcFwx6OT5O5u5eGIY3ekipMjHOQZHGnxcsvjx3Zge5QQyVvpz5ZsKLJdz_STlUyO6dLpGM11JHT7bR2v3DmRy92qqsAMFesXUI-k_qCcHfWblAMAFtNJGb6B-rI5fGzsLTV9QW60ckp1M3PPvWwO14O_jpMAF9zYDbegqVV6Ehvd1Lj7lYrBRjWuMZ6GkWOtW388deytbn2u6c-8l93B1qWW0Vj34AbTd63D95pKs1W6dqR3FRVUd_B3-PGa_xf00ErEueuGkpGfJTM7JGWZf90OHZjwUQ4n9oktjoO_kNqpv9GJyVHtdK72lsLX1datvK4b8bKyY7e793c9v_FSU324llv1zDFXq09gWmHN8xlj2to74WUHx2z-StVcOm--1_B89inu3rvvfpMBMuKOv6PSn83xB1J8E__XYT8koRsq6Q6mMf9E9IvFZRa4GkdGJX_cw-VhmSYpJONGaJS2HEY3ioE4rercPUbATqb8yV9_AdYBCOavwTr0GP8_9npWxq4_IbL2qHYiXUsLWlLhS1nhr46Phpo0xixKqqQaG2rE5hXm-RuD7MFNSH8TP8BLxmeEPKB5WuTRD4iDdzPLPyH13SFFwllIlXlCxzlMsVbAvRo0cWxXjDa-wTuFU0fwJpR6kvcvE8_CoK8IJBndvzlQyDwQ8vJtgTCgcPlKKH-UJx-hfMmPf037fJ8PR_OyQPLwFfnnlJH-luC-UA6GY2OSpLQIIC1ZMU4NuvUufMsbEFxO79jvrOZy9wm2p0LghQ7-hlZ7z2f1jf6-OxrMVyklPra2ae2aixNMvmv6BXVWWtODGx0b1GMi2h2Xz0qUauzGKtVnjm6_f3PJvrbqD9B8y0EP60o38-q_7-JPTjjTvbxBZP0feLi9udL8y1M-TcK8ezn_5EnJ1JMKRliOa8rl-4unGtuLlYWFS_PHexEyu3EmBSveeE3uScb3rGR-01xAHODNxpFtjKXabnq937QLxNNd8lloxmWQ4I6_Y70c1L8IHkNWBsmRePru9tpiA1AbPLxuw0yBwSgNbu7uVgsUfXCB6Y-5T9dcN45ZGuCHPa_2uHslbjD1v1TAjeIuU_eT3EhEMot3LdUM2PKMnUesiAp6BudhWhRBWEQFOduf0wKCbVhVeQmMpWFUlEBpRLckyBLGoDrj5yQgURgGURjFRUKWBYnDLEogzMuUsihFcQA15WLpvGCp9O7Mv788z8Iwj84ELUEY__sWQiQ8YD-JCEHJ1Zk-9_5UtjuD4kBwY82Ri-VWwPnN09tI_-4TDPbviQ2vGwH4-tNZq8X5X3_D6oX8XwAAAP__IyrddQ">