<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/118215>118215</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [llvm][Mips] After c4a60c9d343, Assertion failed: (PhysReg.isPhysical() && "Unallocated register?!"), function useOrDefCSROrFI
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            backend:MIPS,
            llvm:codegen
      </td>
    </tr>

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

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

<pre>
    After `llvmorg-17-init-12447-g`c4a60c9d343 ("[CodeGen][ShrinkWrap] Enable PostShrinkWrap by default") by @sushgokh, building parts of libzfs on FreeBSD for mips asserts with:

```text
Assertion failed: (PhysReg.isPhysical() && "Unallocated register?!"), function useOrDefCSROrFI, file /home/dim/src/llvm/llvm-project/llvm/lib/CodeGen/ShrinkWrap.cpp, line 341.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.      Program arguments: /home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang -cc1 -triple mips-unknown-freebsd13.4 -emit-obj -disable-free -clear-ast-before-backend -disable-llvm-verifier -discard-value-names -main-file-name arc.c -mrelocation-model static -mframe-pointer=all -ffp-contract=on -fno-rounding-math -mconstructor-aliases -funwind-tables=2 -target-cpu mips2 -target-feature -noabicalls -target-feature +soft-float -target-abi o32 -msoft-float -mfloat-abi soft -mllvm -mips-ssection-threshold=0 -debug-info-kind=standalone -dwarf-version=4 -debugger-tuning=gdb -fdebug-compilation-dir=/home/dim/obj/home/dim/src/freebsd/stable-13-llvm-19/mips.mips/cddl/lib/libzpool -fcoverage-compilation-dir=/home/dim/obj/home/dim/src/freebsd/stable-13-llvm-19/mips.mips/cddl/lib/libzpool -nobuiltininc -sys-header-deps -D IN_BASE -D HAVE_ISSETUGID -D LIB_ZPOOL_BUILD -D ZFS_DEBUG -D WANTS_MUTEX_OWNED -D DEBUG=1 -D NEED_SOLARIS_BOOLEAN -O2 -Wno-format-zero-length -Wsystem-headers -Werror -Wall -Wno-format-y2k -Wno-uninitialized -Wno-pointer-sign -Wno-unknown-pragmas -Wno-empty-body -Wno-string-plus-int -Wno-unused-const-variable -Wno-error=unused-but-set-variable -Wno-error=array-parameter -Wno-error=deprecated-non-prototype -Wno-error=unused-but-set-parameter -Wno-tautological-compare -Wno-unused-value -Wno-parentheses-equality -Wno-unused-function -Wno-enum-conversion -Wno-unused-local-typedef -Wno-address-of-packed-member -Wno-switch -Wno-switch-enum -Wno-knr-promoted-parameter -std=iso9899:1999 -ferror-limit 19 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -x c arc-cacfd2.c
1.      <eof> parser at end of file
2.      Code generation
3.      Running pass 'Function Pass Manager' on module 'arc-cacfd2.c'.
4.      Running pass 'Shrink Wrapping analysis' on function '@arc_init'
 #0 0x000000000469d6d8 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x469d6d8)
 #1 0x000000000469b4b9 llvm::sys::RunSignalHandlers() (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x469b4b9)
 #2 0x000000000469de9e SignalHandler(int) Signals.cpp:0:0
 #3 0x0000000829e9257c handle_signal /usr/src/lib/libthr/thread/thr_sig.c:0:3
 #4 0x0000000829e91b4b thr_sighandler /usr/src/lib/libthr/thread/thr_sig.c:244:1
 #5 0x00000008297e32d3 ([vdso]+0x2d3)
 #6 0x000000082a44a5ca __sys_thr_kill /usr/obj/usr/src/amd64.amd64/lib/libsys/thr_kill.S:4:0
 #7 0x000000082e1df0b4 __raise /usr/src/lib/libc/gen/raise.c:0:10
 #8 0x000000082e2934f9 abort /usr/src/lib/libc/stdlib/abort.c:67:17
 #9 0x000000082e1c2871 (/lib/libc.so.7+0x9c871)
#10 0x0000000003f6ee7c (anonymous namespace)::ShrinkWrap::useOrDefCSROrFI(llvm::MachineInstr const&, llvm::RegScavenger*, bool) const ShrinkWrap.cpp:0:0
#11 0x0000000003f6c2cc (anonymous namespace)::ShrinkWrap::runOnMachineFunction(llvm::MachineFunction&) ShrinkWrap.cpp:0:0
#12 0x0000000003bc9cee llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x3bc9cee)
#13 0x0000000004181a50 llvm::FPPassManager::runOnFunction(llvm::Function&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x4181a50)
#14 0x0000000004189ed4 llvm::FPPassManager::runOnModule(llvm::Module&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x4189ed4)
#15 0x0000000004182552 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x4182552)
#16 0x0000000004e92f2f clang::EmitBackendOutput(clang::DiagnosticsEngine&, clang::HeaderSearchOptions const&, clang::CodeGenOptions const&, clang::TargetOptions const&, clang::LangOptions const&, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem>, std::__1::unique_ptr<llvm::raw_pwrite_stream, std::__1::default_delete<llvm::raw_pwrite_stream>>, clang::BackendConsumer*) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x4e92f2f)
#17 0x0000000004eb790d clang::BackendConsumer::HandleTranslationUnit(clang::ASTContext&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x4eb790d)
#18 0x000000000636b569 clang::ParseAST(clang::Sema&, bool, bool) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x636b569)
#19 0x00000000052edc93 clang::FrontendAction::Execute() (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x52edc93)
#20 0x0000000005279e3d clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x5279e3d)
#21 0x00000000053cdefe clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x53cdefe)
#22 0x00000000029e8d64 cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x29e8d64)
#23 0x00000000029e58d5 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#24 0x00000000029e4b82 clang_main(int, char**, llvm::ToolContext const&) (/home/dim/ins/llvmorg-20-init-12945-ga7427410dd7/bin/clang+0x29e4b82)
Abort trap
```

Minimized test case:

```c
// clang -cc1 -triple mips-- -S -mrelocation-model static -target-cpu mips2 -O2 arc-min.c
long arc_all_memory, arc_stats_4_0_0;
long long arc_stats_3_0_0, arc_stats_2_0_0, arc_stats_1_0_0, arc_stats_0_0_0;
void zfs_arc_dnode_limit_percent() {
 arc_stats_0_0_0 = arc_stats_1_0_0 / 2 ?: 4;
  arc_stats_2_0_0 = arc_stats_4_0_0 * arc_stats_1_0_0;
  arc_stats_3_0_0 = arc_all_memory * arc_stats_2_0_0 / 100;
}
```

Note that disabling shrink wrap (using `-mllvm -enable-shrink-wrap-region-split=false`) papers over the problem, but with the full test case I get another regression, which I will submit separately.

</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzEWV9v27iy_zTMC0FDouQ_esiDEsfdAG0TxOnJxXkRKHIkcyOROiSV1P30F6TkyHba7rmL9m6QxNZwOPzNaP6RZNbKWgFcovkVmq8vWO922lyuZSud2edKGMkvSi32l3nlwGC0iJrmpdWmJvGSSCUdiWmaLkmNFhFP2SLimUjSBCO6QpSi-dW1FvABFJqv0fxquzNSPT8Z1qH5Gt8oVjaA77V10wAu91hAxfrGeQE08wSURra3u1o_7xC9xmUvGyFVjTtmnMW6wo0sv1UWa4U3BuBqu8aVNriVncXMWvBcr9LtUJKjKPwuouHXwVeHojwPTFIrXDHZgEBJ7lW43-3tA9Qzaf03yVkT9MowogtEFxhR-kWxptGcORDYQC2tA4OSDaLxAN_jrXrFg_Dewp1ZQ3W9fbgzm9swJhvAiG52ugVEN0K2iG6s4YhuvKXHD9IZ_Sdwd0SVJaKbg3XpZrLgjHedl9xIBThJ4xmK8vuPN_n2Btu-bKXDDJd9jQ102jjsNN4511lvG7pBdFNLt-vLGdftDzFIa3uwiG4wUwJLxZteAHY7wNwwu8Ml48_OMA4eR2egM5qDtSCw1b0ZyH4ms1ZzOdiuV9hyIzvn8W4d489Y9G03vLJohsPPvdG1YS1mpu5bUM4OL-rUelLZEbL3Uxod_DRL56Rmy5Qu0zgSYonoppTedrxhqsaE8xgTZ2TXQHAd0qtnpV8VqQxAaUWczFJMoJWO6PJPTIS03oHDMCa8AWYIs46UUGkDxBsBlJj4ghFfwMhKgglkzowgL6zpgSjWgsWkZVIR7xOBgJnhM45JayD4mNSKtFpAg61jTvqRyrAWSKelCo63Zk2DSVV1hGvlX4FDyVorTCqlidG98nFDWuZ2mLRcK-tMz502hDWSWY-g6tWrVII4j9miZE0xcczU4Ajv-mCYiVIBc70BTJRmpY-Pxr4bQ_TK6sqRqtHMvY2yUmKdUEza48E2fIZBT8ak9UbDJLwOayGEEXE7A3anG4GSdYSJgLKviVSVJs9SeaJ1TAnWaAWYiFdmKm92K7VCyTodJ9RgiOuVVDVK1rUoMakGQVy3nWwGYwvpbXruYLr88_sROzqKfw7mI3EyvPU4Q3TjlZj5f97lhGjeothnr05r_-K4fgHDavhHUSjtM6yTSiqOid1bsgMmwBABncVkjW8_F1c-n5A1_iP_101xu93ePH75cLv2lI-3V8W_7-_uPhZXX24_BtK_N9tifXP15YN_eMo_P26LT18eb_6nuHv6fBM4wihK1rF_-Hxzsy62dx_zh9ttcXV39_Em_4zJHcXkSWlSadMyR76B0aQBVXtXfrJ766AdcVpMnsAYbTB5CvFwNG1Pn4dn_-qlk6yR30AMpDGKiK-JB6YhA3SG1S2zAxHazu2Jr4rDs3XGB1XX9JZI5Q4zewuChBAjL8zIUOuG-R4aStYjS9k7YuFHTMwYticd82HuK_DJoIDOQKg9RGmPUjvt9t3P1zmT5VjvdKNrH73B65iBExVCfhoNxAwotwMLlsB_etZItz_hfat0AwDVt94CY_CdcPp81hAPVkA1jDAhDFhLdEU6nzsFaaEtDzjtq3R8d_w9yB8Iz8p47VvtTXGkoHU-HUirs1WWoSSPsyzDpAqWIY3vcnDsCbXq-XGOmNFZjMkL-NQovwFptPaePxFs02FSecRW1pisi-LD9XURgmH9lD9saHG9uS3y7afBp79i7nM54YxXgs44ivJ4LGkouQZdoeTGdzMWDGYO-7Khq9AboCinI6cv9rgGBSakBRTlyTjy0Cs19EPWYkSXm8NruPeET0yxGgyiS98gtVr0oeVYngCiS1930x8IHLoL7NuLztOZYs3eSjvKfHvtiC5RGjHDCx9c_iny9TmJcPQ1Ovyki0wsxAqH3iLJUZLbvR2-3BupXCj-j0P7sJqYDHsttHUGWBvar2sslRuasdWvaQEQvYq-juh86zZgj8-wl2mZfQ_7Q6-2slas-YMp0YCxb73iL4bnAUzw6LlpIQN8AgTR1WipgWxDh5jkUfgbpCSTlBXNIKPzJce7ML-wYZZvs3prpu70UDTczhN9TWZi-OJnzPi4QjKukJ6tEJdpiUfmYSHzd5agaerjelxkfrLIEhIqhr3I_OpFWO13Id6IVCSTARfHc1iasjlnuCjs3hZ-oWfZHOk-FN1jkKwVi3QW_h9D9m4xIPUCZluU5OmRvZfHi0IsqqhMcVEYJi380Az-oQ7dfuB7M3F8kLo6kUqzJK0yzErf5v9MpnVieA6sQexi6eUewjc7RcvpahmPfj0Jmlk9WwbzZny1jAcD-_g5Cf6kWgAsuZ_NlFb7VvcWh-a3CwGfDcF0tFMMz-92TkeJ4RPjO6ng1jezOBTcMT9MLA9Qbzl7ARXyYB42kVo3PibCBHy2fZqCwysQnynAKf8_K2B6dadGpIf0_D0tprFFiNif4ToJ_aTkGQfAP5Toa8ERlu-COFv916auEeHkGMlJ6opXMZtHR_g39x7yoXr9k8hHbBPy9Ax5BiL9L5B_CrX39LWPpN-D2uOaUM_PUNP5nB6hbqBmfD8W4gn_bds1bzr8P2L36CbsixPskNGKVnjgD1huWumuhh33Xe-63iG6OhpeS1YrbZ3k9kbVUsGYIo5Y_gh7hy0ww3d3nfcle5JNjljHY5e_4HoMO92_YPrIVP09lsnK27C9eIDqlHwwfn4mcDRCPkbD8ZRb5Uxv5Qs8QHWt3L0zKLmehl-qMT9sZAPbsKFCyY0XEdpoP1IU8ZiPlfxPD0V3JsL3aN2rkQ6KQ6f2vdnjAV8hoAEHfyEhuRlRvFfyWivbt2NK_-UuODjZ5ILLUxcsl1kkfgZq8KrQ2jwapuywm_8SGuNj38y3j9dahZPI3xJKA9JJj9WxHotkUc4X2bEe934fkm8fT1FuoWWjbw6lcyqhvxbviGjCmx3jnVMQPEuO8W6Mt96byw_p4Cvw3sFvacFHCG8AaXQKcJlBIk7TRdvJBozvUJjicALxEKirH2v0O7xihDkpcdLkzBMuoIKTBDvAnXR5GU8kT6G_0_V3hOYIbwJ_0gnRDFZikWLO46Jl8rRm5cawvU-myTXfsbd-MT_kmBMavcYvWorfosOIctIhOdNhvhJzfLD6dfwYgu1Ik23LmuZf4URiKNHfUeislHgZY6o5KjYZFka-gHnfYdL0DFNarujgFAfLhp3lYLdgpvy_W_GX29IjG2yZh_2O85330UXPcO_zSSrZhgM_B9Zhziy8vxPiQfkNohv8o5sBgsn2Z8fy7w_M72g4AGqlCqc_jVa1JxSsaYoWWm324VLE8MLLsEVaREWEkqsD79uEYTgJwycz6HtS_J4UTXK9a-NvlS38qFBaQBGOxIoODAf_XofkufTM5yIwStbnK_lNJqYYJRuU5DgdVsHnEM9mpuPM_B3ud9OTk-mT5c5m0zcscTRKQcv1e2f4rB1gt2MODzc0UtXYDgddr4Z13kd764loER0uIiDcWZKBjXg2YqD2DmC7RjqUrCvWWPBr0Ax3rANjsX4BE27HOqPLBtrhDtOFK8lAr_qmmTwS3-IaHGZKux0YbKA2YO3Yzb3uJN_hW_wqm-Zwn2ehY4Y5aPYzFOUX4jIRWZKxC7iMl0kSLZKMZhe7S4hZmoloVYplllTlSqTAlslqyZKMMx5XF_KSRjSNaRTHabJKV7PFsppnVZJRyJasqkqURtAy2cy8MWba1BfhJvAyjlc0nl80rITGhrtkSsfrL9-p3t5vw2XoNaJ0TA1cCwhHGRTN1xfmMtxPlH1tURo10jo7LeGka8IFdZga7pE_yc6i-RoPl9JH987eQv_MXe5Fb5rLv3-ROlrw5ZL-bwAAAP__3OvX2w">