<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/139060>139060</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang] Crash at -O2: Assertion `(BestFactor.Width == LegacyVF.Width ... failed
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          cardigan1008
      </td>
    </tr>
</table>

<pre>
    This code crashes at `-O2`:

```c
int *a;
int b;
void c(int d, int *g) {
 int e, f = g[0];
  e = 0;
  for (; e < d; e++) {
    a[e] = f + g[e + 1] - g[e];
    g[e] = f + g[e + 1];
  }
}
void h(int d, int g) { c(d, &g); }
void i() {
  int j = 0;
  if (b)
    j = 1;
  h(j + 2, 4);
}
void main() {}
```

Compiler Explorer: https://godbolt.org/z/b1aTErPW1

Bisected to https://github.com/llvm/llvm-project/commit/673a4671f3e8b7158d990f6456428175a6eac38c, which was committed by @nikic 

Crash:

```console
clang: /root/llvm-project/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:7667: llvm::VectorizationFactor llvm::LoopVectorizationPlanner::computeBestVF(): Assertion `(BestFactor.Width == LegacyVF.Width || BestPlan.hasEarlyExit() || planContainsAdditionalSimplifications(getPlanFor(BestFactor.Width), CostCtx, OrigLoop) || planContainsAdditionalSimplifications(getPlanFor(LegacyVF.Width), CostCtx, OrigLoop)) && " VPlan cost model and legacy cost model disagreed"' failed.
```

Backtrace:

```console
Stack dump:
0.      Program arguments: /opt/compiler-explorer/clang-assertions-trunk/bin/clang -gdwarf-4 -g -o /app/output.s -mllvm --x86-asm-syntax=intel -fno-verbose-asm -S --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics -O2 <source>
1.      <eof> parser at end of file
2.      Optimizer
3.      Running pass "function<eager-inv>(float2int,lower-constant-intrinsics,loop(loop-rotate<header-duplication;no-prepare-for-lto>,loop-deletion),loop-distribute,inject-tli-mappings,loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>,infer-alignment,loop-load-elim,instcombine<max-iterations=1;no-verify-fixpoint>,simplifycfg<bonus-inst-threshold=1;forward-switch-cond;switch-range-to-icmp;switch-to-lookup;no-keep-loops;hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,slp-vectorizer,vector-combine,instcombine<max-iterations=1;no-verify-fixpoint>,loop-unroll<O2>,transform-warning,sroa<preserve-cfg>,infer-alignment,instcombine<max-iterations=1;no-verify-fixpoint>,loop-mssa(licm<allowspeculation>),alignment-from-assumptions,loop-sink,instsimplify,div-rem-pairs,tailcallelim,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;speculate-unpredictables>)" on module "<source>"
4.      Running pass "loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>" on function "i"
 #0 0x0000000003f7c0a8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3f7c0a8)
 #1 0x0000000003f79d34 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3f79d34)
 #2 0x0000000003ebebf8 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x0000769685242520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007696852969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x0000769685242476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007696852287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x000076968522871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x0000769685239e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x0000000005af0736 llvm::LoopVectorizationPlanner::computeBestVF() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5af0736)
#10 0x0000000005b066aa llvm::LoopVectorizePass::processLoop(llvm::Loop*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5b066aa)
#11 0x0000000005b09280 llvm::LoopVectorizePass::runImpl(llvm::Function&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5b09280)
#12 0x0000000005b098d3 llvm::LoopVectorizePass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5b098d3)
#13 0x0000000005669c1e llvm::detail::PassModel<llvm::Function, llvm::LoopVectorizePass, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x5669c1e)
#14 0x000000000391d5f0 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x391d5f0)
#15 0x0000000001200d3e llvm::detail::PassModel<llvm::Function, llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x1200d3e)
#16 0x000000000391bec3 llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x391bec3)
#17 0x00000000011ffb8e llvm::detail::PassModel<llvm::Module, llvm::ModuleToFunctionPassAdaptor, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x11ffb8e)
#18 0x000000000391b8d0 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x391b8d0)
#19 0x00000000042309de (anonymous namespace)::EmitAssemblyHelper::RunOptimizationPipeline(clang::BackendAction, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>&, std::unique_ptr<llvm::ToolOutputFile, std::default_delete<llvm::ToolOutputFile>>&, clang::BackendConsumer*) BackendUtil.cpp:0:0
#20 0x0000000004233a61 clang::emitBackendOutput(clang::CompilerInstance&, clang::CodeGenOptions&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>, clang::BackendConsumer*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4233a61)
#21 0x000000000491e800 clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x491e800)
#22 0x00000000065f0c0c clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x65f0c0c)
#23 0x000000000491ebe8 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x491ebe8)
#24 0x0000000004c11f15 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4c11f15)
#25 0x0000000004b9131e clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4b9131e)
#26 0x0000000004d05d39 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4d05d39)
#27 0x0000000000da788f cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xda788f)
#28 0x0000000000d9da5a ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#29 0x00000000049854a9 void llvm::function_ref<void ()>::callback_fn<clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const::'lambda'()>(long) Job.cpp:0:0
#30 0x0000000003ebf094 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3ebf094)
#31 0x0000000004985abf clang::driver::CC1Command::Execute(llvm::ArrayRef<std::optional<llvm::StringRef>>, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char>>*, bool*) const (.part.0) Job.cpp:0:0
#32 0x0000000004947f0d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4947f0d)
#33 0x0000000004948f9e clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4948f9e)
#34 0x0000000004950df5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4950df5)
#35 0x0000000000da37f8 clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xda37f8)
#36 0x0000000000c28b74 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xc28b74)
#37 0x0000769685229d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#38 0x0000769685229e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#39 0x0000000000d9d505 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xd9d505)
```
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJzkWt1y47aSfhr4BkUVCf6IvPCFTI_2JJXUTI19ci5dIAhKiEGAC4C2laffAkCKpCw79hnl1G42pYwl_HR__XWj0QCJtWY7Qek1SG9AenuFe7OX6ppgVbMdFlEY5leVrA_X93umIZE1hURhvacaYgNBFgZfEchCEG9A6D5Z6D8EhBsmDARog0F8M_yq_NcnyWpIAMptWw1QCYehO4AKCNZ2jGuitq-BIL6FO5DehCC99RIgpK41HH82UkGAchDfuJ4S1u4rQDfuc5QKIcQgvaEgvXUCGgjQjRNO3bfIdgS-YaYNHlvenDUOBetbS4T71xm6PzV0tNJR4FoBymyjhTybyKxBM-h27u9Ls5lFkld2rofp-6Ox3-r-3UFEVk_ilSzxtZiJmSYPf_Sjd2sp245xquCXl45LRRWIN3BvTKet59EWoO1O1pXkZiXVDqDtHwBtqwjff1Hf_hV5GTdMU2JoDY08ncrMvq9WRLYAbTl_Gv8EnZK_U2IA2hLZtsx-ydYxTrJ11MQ0r9ZRmtdFETZZkmYJyqN1ijOKSZwTa-3znpE9fMY2cO10q7w6QJCEgj0yAgfbbDyfCWAptOQUhBvCsdhZgwHaKinNa3QjZlYBtL1XWOhGqlYDtP2NEiMV-4MCtP1Fyu74e0W6DsSbdZatrWgnId6AeDOOwIZJscX2x6x3LsON-MaxEM4fIN4Q2Xa9oTdUm9-23qVW-EZrquxgu2ABym2_l7z6F6vN3oaMjZpf6A6Tw2_bsXVdgnUJ7WirZbXH-gtW_PDlxXpiiBc3pONYlFIYzITe1DWzujC_Y23HWcOIA6oBynfUSdpKdQaFBYtKWEptSvNiv35VbGcN_lFNS7ve1eNUoQygDAKE4G9WCCRSG9jKmnKIRQ25EzdvrZnGO0VpDRACaA0bzDitV6_X0Q0mj0ZhQt-LtzuDySOs-7bzo8IVCItvSu4UbiFWu76lwughIGU3LA-3PgM6rk-0dWEb4NH3OjCqF492Xdrl7rthsKufsWqCBAY7GEgrEXedldubrjcrDYPWRh8Mgpc8C7BuA30QBr-A-JYJQzkMGiGDJ6oqqanth8EdDIIdIYGRkpO9TS7x7btI7WAtcKf30sCgIZJLFdQM74TUhhHtdbh9Z9n8FdlUr2WvLKNfQLiJLFcgLqlsQPwFdlhpquxWRUUNZQMb5ihGdtjXzrCW_UEVCDexbfjeC8HEDnZYa-v-phfEUmfl4R1VARNPVg3KGy6xQUwYgEoun6kKrPsMFiZgwigmNCPa9dmoyu2fQEmDDQVxuae4piqo-44PEQviGyGDTtEOKxo0UgXcSKfJSQhqyqkb50LXNzFtFKt6Y7dIJmwiCgxnQYu7jondqDx4OiaguBTSoqOKU_zk1BBaB1Lwg9d_HHrS5YEw0VAVYM52wsbfKJ9LXAeUs9YN0YbItmLCamvxS8AMVcOajG-jUY1izSFo2EsnLYNOuvYr-ECaHYjLSopeB1ZcYPaK6r3k9SCgkeoZqzrQz8yQvaXdbvTDL4XFjgZGBozYxTM2GxlwKR_7zgN4pNTilnYHutlLpk1g9wcpnEbtB_l2a50OtJGK6uCZGa8waHDPDbObwo1m4vF0uu4o6Tk2NKi4JI-uabDPz68UFmTvFU2De9EpWjNicMWpHnjhMxcqgEr_Ixhp_iHSnQN7oSTnIC6_It9qxv0reMbKrgcLQ0kM4rJTVFP1RAPnpvNR8aN4Wq2xXTKMtCAuMefyeaTIrZQvfhEcVQaNkq1Nc33bDdnfC7KeGfCM7ANU1uwpULQNOsyUHWow4wRzPoTwh-NQyOBToWg9_ToaF6F4jLqTcPpoKFoVPxSN74ZiYfdDKeyO13Nb9aJF6kUIhJvkXBa9aBpyEMa8bKUzrxkCFIcwfAnH_-JmTUKcz0onfdD-yzfFhHGb7L3bilE-DVL4-UFqoyhuXRngCnZfFOQ_vNsCdBO-DMCGih2gODqBXdRxcg52ySkWffdV3LGdwBygvBfu8FZDLsXu0iAtjAkkWoCkFa2aHLrK-Tsl8omqg0f1DyxqbnXlA2-LMbZyoy9mqH1D97-XHw_y11mR5SlKUIrCwRxfVb_k2UOWBJyJ_iXYid53kJWWq8xBdlMmwMlSYJEVDYGdXcW4fnhknH9Oups_SU9P4SbrDO60o-CzsJN1NgnOloJRvm5iiCupzOfEuomT2PUrsVH1aYFRNQnMlwLjghbZ5wS6KZPAYh5gKW7CdZz9yLnncmthAOOh2vW6yDNpFWYZxm9Apd-wHpZvpyShWv8yVISL4QBtLgvZg5ogRyeQC5SHfw5Z9eKntuMLuNuxJrbZ8bKQLagJMjqFnNfxhyC_Dbeczd8IzA-a6V-xsKU9iMszk-yOc3kz8zqezIwXZmZZQSI6g1lTW6AM-xbW-ld73jwPdmHea3r-Levt5_8ErZ64idZksV8VUZ0284B3VL4H8W_N1sDHxFY6ZytCYVjHlwjCv4zlv7V3Bv4n72QnsVxRMs-Ev7qC_F6OkCzrmxp3RqrzBvsJnzJ3mPKXhKI1ZzJ2vQjFqGmq_HOhOFpXfpCif4ODtyLpfxOxA3UTsflpFOX1RzLiOTr_PiwNPEwsLcrQBMVhUduzbo6FFIdW9hoK3FLduXNj4dF9aZnZaE3bih_-QXk3VqXfezFcMfqKlXWUuzubfHyiAGJ3I0xFvTkmRG1q39ML9t89fejMkgt7Qu2eFTP0YTynzibV1F0IPLgbQ_onE4dkmn1E7b2U_Ku7E94yHw8f0Xkya67wNQelFLpvrQNdNTy0_tMwfnJgtOfR8MRRMc6iuUzaMjNI8ACWtI8PtH5yt7aEvgZVypr-F3UedJdKJ-F6ZxQTu--0OZdpnAXnTNyc2fd-Ekb1mj3R77Qphfl2QvxTM5S2lsG7gza0HbbA_3ykfMBrF1uag0-PSxMtzjBJEdE8DN_D4xr9fYR7JOcvEP8p2EkobO7uh3uJS2eXAeRkwuJMk6VNSEIyN-EbVppu7u6XAO9oi4f4q6Tk098LQh3ATFDjU7Yrmp9ZHkNA-zz4Qklv6Bjjlz2FDxAmgIsKPyFR1ETpHOBWWacel9wc4cWxee0TtkU9nVRFFEcUvpd9zvL3tjGXjlOPcMK_qDiTOkzruJjjH5BOZjzJ4UHWnyTZC6cIj2zCvSgewxqv87yBhEQPwysOs2pDKXyw2TsuyR4r6B7fWXxDmlu0oRI-SVZfGr7HN6HPl-iLGqcYjlSX0b1b8zMb7lrMuT_ku2uac6ac7FpWxpDsxnEulGrFnqg6s80u66EiTxNcODJmQsfr-Afl-HS948sHQw1IMOcVJo8PjbAwpxDxiodwKaNSti0W9elqPeu3404mO_8WwGIPm_bn4951nPDwQF5eosj_qLBmxO5z7iGKo3Ax2DY8GIWZ0WP3iTjMuQ1_e9w69tshmylTu8DxhLspAK05bqsaA7SeqEL5eJH_s6xeO-PkAQetmrCYPyk4d9V-rETvcEP5YcHl-367aJntsR5DPY5OwwpXDfz_HBaW61WHlVmFb_sfLVlL1k1Yv8ma8xd-tfeNVC4S9clEO2CWHsp3dMyHbhZFysywS1UAzuApiE5KlCRvCvpZOn6WlX6bi59l9QvTZsHFe_n36PsOM-t2_4LIh-mbH4_-OhItTROJyzKqSMO6Sd8CfDv7vigBzuz9b5H_HyTxotWnI2aiLT2pNOJ1M5THY60xwnaJYzMs-z_fiS9YXVhME-JFTRcSlFfrxL36eTmVXuik8vSpY1EXn3yo66ZMAvNTgTQJ4cODnfOgDVbmYWbQh1XQZKaiOC3C0jCFXvgFfePEDkrHFwCv6uu4LuICX9HraJ1k6zBah8nV_jqP8rwq6iTKad0kRRbHYZGukyopcE5DEl-xaxSiNEzDPArTNExWJCMoStOEVg0tcJqBJKQtZnxl428l1e6Kad3T6yguwiy84riiXLtXwBEaUCKQ3l6pa_eia9XvNEhCzrTRkwjDDHfvjfsZ6a1_1g-xgcFX9APvna5Wq-ENyqte8etPvyvsbNMAbQfznq7R_wQAAP__A5-jRg">