LLVM 18 regression: SelectionDAG/LegalizeDAG.cpp:991: void {anonymous}::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*): Assertion `(TLI.getTypeAction(*DAG.getContext(), Op.getValueType()) == TargetLowering::TypeLegal || Op.getOpcode() == ISD::TargetConstant || Op.getOpcode() == ISD::Register) && "Unexpected illegal type!"' failed

[andrewrk]

version: LLVM 18.x branch (commit 78b99c7)

The Zig compiler fails to build from source after updating to LLVM 18.

reduced.ll:

target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

define fastcc void @"fmt.parse_float.decimal.Decimal(f16).leftShift"() #0 {
  br label %1

1:                                                ; preds = %7, %2, %0
  %.sroa.02.0 = phi i64 [ 0, %0 ], [ -1, %7 ], [ %4, %2 ]
  %.sroa.0.0 = phi i64 [ 1, %0 ], [ %3, %7 ], [ %3, %2 ]
  %.not = icmp eq i64 %.sroa.0.0, 0
  br i1 %.not, label %6, label %2

2:                                                ; preds = %1
  %3 = add i64 %.sroa.0.0, 1
  %4 = add i64 %.sroa.02.0, -1
  %5 = icmp eq i64 %.sroa.02.0, 0
  br i1 %5, label %7, label %1

6:                                                ; preds = %1
  ret void

7:                                                ; preds = %2
  %8 = getelementptr [768 x i8], ptr null, i64 0, i64 %4
  store i8 0, ptr %8, align 1
  br label %1

; uselistorder directives
  uselistorder i64 %3, { 1, 0 }
}

attributes #0 = { "target-features"="-16bit-mode,-32bit-mode,-3dnow,-3dnowa,+64bit,+adx,+aes,+allow-light-256-bit,-amx-bf16,-amx-complex,-amx-fp16,-amx-int8,-amx-tile,+avx,-avx10.1-256,-avx10.1-512,+avx2,+avx512bf16,+avx512bitalg,+avx512bw,+avx512cd,+avx512dq,-avx512er,+avx512f,-avx512fp16,+avx512ifma,-avx512pf,+avx512vbmi,+avx512vbmi2,+avx512vl,+avx512vnni,-avx512vp2intersect,+avx512vpopcntdq,-avxifma,-avxneconvert,-avxvnni,-avxvnniint16,-avxvnniint8,+bmi,+bmi2,+branchfusion,-ccmp,-cf,-cldemote,+clflushopt,+clwb,+clzero,+cmov,-cmpccxadd,+crc32,+cx16,+cx8,-egpr,-enqcmd,-ermsb,-evex512,+f16c,-false-deps-getmant,-false-deps-lzcnt-tzcnt,-false-deps-mulc,-false-deps-mullq,-false-deps-perm,-false-deps-popcnt,-false-deps-range,-fast-11bytenop,+fast-15bytenop,-fast-7bytenop,+fast-bextr,-fast-gather,-fast-hops,+fast-lzcnt,+fast-movbe,+fast-scalar-fsqrt,+fast-scalar-shift-masks,-fast-shld-rotate,-fast-variable-crosslane-shuffle,+fast-variable-perlane-shuffle,+fast-vector-fsqrt,-fast-vector-shift-masks,-faster-shift-than-shuffle,+fma,-fma4,+fsgsbase,+fsrm,+fxsr,+gfni,-harden-sls-ijmp,-harden-sls-ret,-hreset,-idivl-to-divb,-idivq-to-divl,+invpcid,-kl,-lea-sp,-lea-uses-ag,-lvi-cfi,-lvi-load-hardening,-lwp,+lzcnt,+macrofusion,+mmx,+movbe,-movdir64b,-movdiri,+mwaitx,-ndd,-no-bypass-delay,-no-bypass-delay-blend,-no-bypass-delay-mov,-no-bypass-delay-shuffle,+nopl,-pad-short-functions,+pclmul,-pconfig,+pku,+popcnt,-ppx,-prefer-128-bit,-prefer-256-bit,-prefer-mask-registers,-prefer-movmsk-over-vtest,-prefer-no-gather,-prefer-no-scatter,-prefetchi,-prefetchwt1,+prfchw,-ptwrite,-push2pop2,-raoint,+rdpid,+rdpru,+rdrnd,+rdseed,-retpoline,-retpoline-external-thunk,-retpoline-indirect-branches,-retpoline-indirect-calls,-rtm,+sahf,+sbb-dep-breaking,-serialize,-seses,-sgx,+sha,-sha512,+shstk,-slow-3ops-lea,-slow-incdec,-slow-lea,-slow-pmaddwd,-slow-pmulld,+slow-shld,-slow-two-mem-ops,-slow-unaligned-mem-16,-slow-unaligned-mem-32,-sm3,-sm4,-soft-float,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+sse4a,-sse-unaligned-mem,+ssse3,-tagged-globals,-tbm,-tsxldtrk,-tuning-fast-imm-vector-shift,-uintr,-use-glm-div-sqrt-costs,-use-slm-arith-costs,-usermsr,+vaes,+vpclmulqdq,+vzeroupper,-waitpkg,+wbnoinvd,-widekl,+x87,-xop,+xsave,+xsavec,+xsaveopt,+xsaves" }

[nix-shell:~/src/zig/build-llvm18-release]$ ~/local/llvm18-assert/bin/clang -c reduced.ll -O3
clang: /home/andy/dev/llvm-project-18/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:991: void {anonymous}::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*): Assertion `(TLI.getTypeAction(*DAG.getContext(), Op.getValueType()) == TargetLowering::TypeLegal || Op.getOpcode() == ISD::TargetConstant || Op.getOpcode() == ISD::Register) && "Unexpected illegal type!"' failed.
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/andy/local/llvm18-assert/bin/clang -c reduced.ll -O3
1.      Code generation
2.      Running pass 'Function Pass Manager' on module 'reduced.ll'.
3.      Running pass 'X86 DAG->DAG Instruction Selection' on function '@"fmt.parse_float.decimal.Decimal(f16).leftShift"'
 #0 0x000000000387f4db llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/andy/local/llvm18-assert/bin/clang+0x387f4db)
 #1 0x000000000387c83b llvm::sys::RunSignalHandlers() (/home/andy/local/llvm18-assert/bin/clang+0x387c83b)
 #2 0x00000000037c1508 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x00007f2075454a70 __restore_rt (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x3da70)
 #4 0x00007f20754a3ddc __pthread_kill_implementation (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x8cddc)
 #5 0x00007f20754549c6 gsignal (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x3d9c6)
 #6 0x00007f207543d8fa abort (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x268fa)
 #7 0x00007f207543d819 _nl_load_domain.cold (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x26819)
 #8 0x00007f207544d3c6 (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x363c6)
 #9 0x00000000048a69fa (anonymous namespace)::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*) LegalizeDAG.cpp:0:0
#10 0x00000000048b3100 llvm::SelectionDAG::Legalize() (/home/andy/local/llvm18-assert/bin/clang+0x48b3100)
#11 0x000000000499c826 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/home/andy/local/llvm18-assert/bin/clang+0x499c826)
#12 0x00000000049a06ac llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/home/andy/local/llvm18-assert/bin/clang+0x49a06ac)
#13 0x00000000049a2257 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (.part.0) SelectionDAGISel.cpp:0:0
#14 0x0000000002409ff5 (anonymous namespace)::X86DAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&) X86ISelDAGToDAG.cpp:0:0
#15 0x0000000002c30325 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
#16 0x0000000003213619 llvm::FPPassManager::runOnFunction(llvm::Function&) (/home/andy/local/llvm18-assert/bin/clang+0x3213619)
#17 0x0000000003213751 llvm::FPPassManager::runOnModule(llvm::Module&) (/home/andy/local/llvm18-assert/bin/clang+0x3213751)
#18 0x0000000003214057 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/home/andy/local/llvm18-assert/bin/clang+0x3214057)
#19 0x0000000003aedb33 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::unique_ptr<llvm::raw_pwrite_stream, std::default_delete<llvm::raw_pwrite_stream>>, clang::BackendConsumer*) (/home/andy/local/llvm18-assert/bin/clang+0x3aedb33)
#20 0x00000000040cd0fa clang::CodeGenAction::ExecuteAction() (/home/andy/local/llvm18-assert/bin/clang+0x40cd0fa)
#21 0x000000000434b2c9 clang::FrontendAction::Execute() (/home/andy/local/llvm18-assert/bin/clang+0x434b2c9)
#22 0x00000000042d0c02 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/home/andy/local/llvm18-assert/bin/clang+0x42d0c02)
#23 0x000000000441906f clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/andy/local/llvm18-assert/bin/clang+0x441906f)
#24 0x0000000000b7b6ca cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/home/andy/local/llvm18-assert/bin/clang+0xb7b6ca)
#25 0x0000000000b736a7 ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#26 0x000000000410e509 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
#27 0x00000000037c1962 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/home/andy/local/llvm18-assert/bin/clang+0x37c1962)
#28 0x000000000410fbf4 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
#29 0x00000000040d6ae5 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/home/andy/local/llvm18-assert/bin/clang+0x40d6ae5)
#30 0x00000000040d75dd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&, bool) const (/home/andy/local/llvm18-assert/bin/clang+0x40d75dd)
#31 0x00000000040e1bb4 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/home/andy/local/llvm18-assert/bin/clang+0x40e1bb4)
#32 0x0000000000b78d69 clang_main(int, char**, llvm::ToolContext const&) (/home/andy/local/llvm18-assert/bin/clang+0xb78d69)
#33 0x0000000000a6feb3 main (/home/andy/local/llvm18-assert/bin/clang+0xa6feb3)
#34 0x00007f207543efce __libc_start_call_main (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x27fce)
#35 0x00007f207543f089 __libc_start_main@GLIBC_2.2.5 (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x28089)
#36 0x0000000000b72315 _start (/home/andy/local/llvm18-assert/bin/clang+0xb72315)
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
clang version 18.1.5 (https://github.com/llvm/llvm-project 78b99c73ee4b96fe9ce0e294d4632326afb2db42)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/andy/local/llvm18-assert/bin
clang: note: diagnostic msg: Error generating preprocessed source(s) - no preprocessable inputs.

[llvmbot]

@llvm/issue-subscribers-bug

Author: Andrew Kelley (andrewrk)

version: LLVM 18.x branch (commit 78b99c7)

The Zig compiler fails to build from source after updating to LLVM 18.

reduced.ll:

target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

define fastcc void @"fmt.parse_float.decimal.Decimal(f16).leftShift"() #<!-- -->0 {
  br label %1

1:                                                ; preds = %7, %2, %0
  %.sroa.02.0 = phi i64 [ 0, %0 ], [ -1, %7 ], [ %4, %2 ]
  %.sroa.0.0 = phi i64 [ 1, %0 ], [ %3, %7 ], [ %3, %2 ]
  %.not = icmp eq i64 %.sroa.0.0, 0
  br i1 %.not, label %6, label %2

2:                                                ; preds = %1
  %3 = add i64 %.sroa.0.0, 1
  %4 = add i64 %.sroa.02.0, -1
  %5 = icmp eq i64 %.sroa.02.0, 0
  br i1 %5, label %7, label %1

6:                                                ; preds = %1
  ret void

7:                                                ; preds = %2
  %8 = getelementptr [768 x i8], ptr null, i64 0, i64 %4
  store i8 0, ptr %8, align 1
  br label %1

; uselistorder directives
  uselistorder i64 %3, { 1, 0 }
}

attributes #<!-- -->0 = { "target-features"="-16bit-mode,-32bit-mode,-3dnow,-3dnowa,+64bit,+adx,+aes,+allow-light-256-bit,-amx-bf16,-amx-complex,-amx-fp16,-amx-int8,-amx-tile,+avx,-avx10.1-256,-avx10.1-512,+avx2,+avx512bf16,+avx512bitalg,+avx512bw,+avx512cd,+avx512dq,-avx512er,+avx512f,-avx512fp16,+avx512ifma,-avx512pf,+avx512vbmi,+avx512vbmi2,+avx512vl,+avx512vnni,-avx512vp2intersect,+avx512vpopcntdq,-avxifma,-avxneconvert,-avxvnni,-avxvnniint16,-avxvnniint8,+bmi,+bmi2,+branchfusion,-ccmp,-cf,-cldemote,+clflushopt,+clwb,+clzero,+cmov,-cmpccxadd,+crc32,+cx16,+cx8,-egpr,-enqcmd,-ermsb,-evex512,+f16c,-false-deps-getmant,-false-deps-lzcnt-tzcnt,-false-deps-mulc,-false-deps-mullq,-false-deps-perm,-false-deps-popcnt,-false-deps-range,-fast-11bytenop,+fast-15bytenop,-fast-7bytenop,+fast-bextr,-fast-gather,-fast-hops,+fast-lzcnt,+fast-movbe,+fast-scalar-fsqrt,+fast-scalar-shift-masks,-fast-shld-rotate,-fast-variable-crosslane-shuffle,+fast-variable-perlane-shuffle,+fast-vector-fsqrt,-fast-vector-shift-masks,-faster-shift-than-shuffle,+fma,-fma4,+fsgsbase,+fsrm,+fxsr,+gfni,-harden-sls-ijmp,-harden-sls-ret,-hreset,-idivl-to-divb,-idivq-to-divl,+invpcid,-kl,-lea-sp,-lea-uses-ag,-lvi-cfi,-lvi-load-hardening,-lwp,+lzcnt,+macrofusion,+mmx,+movbe,-movdir64b,-movdiri,+mwaitx,-ndd,-no-bypass-delay,-no-bypass-delay-blend,-no-bypass-delay-mov,-no-bypass-delay-shuffle,+nopl,-pad-short-functions,+pclmul,-pconfig,+pku,+popcnt,-ppx,-prefer-128-bit,-prefer-256-bit,-prefer-mask-registers,-prefer-movmsk-over-vtest,-prefer-no-gather,-prefer-no-scatter,-prefetchi,-prefetchwt1,+prfchw,-ptwrite,-push2pop2,-raoint,+rdpid,+rdpru,+rdrnd,+rdseed,-retpoline,-retpoline-external-thunk,-retpoline-indirect-branches,-retpoline-indirect-calls,-rtm,+sahf,+sbb-dep-breaking,-serialize,-seses,-sgx,+sha,-sha512,+shstk,-slow-3ops-lea,-slow-incdec,-slow-lea,-slow-pmaddwd,-slow-pmulld,+slow-shld,-slow-two-mem-ops,-slow-unaligned-mem-16,-slow-unaligned-mem-32,-sm3,-sm4,-soft-float,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+sse4a,-sse-unaligned-mem,+ssse3,-tagged-globals,-tbm,-tsxldtrk,-tuning-fast-imm-vector-shift,-uintr,-use-glm-div-sqrt-costs,-use-slm-arith-costs,-usermsr,+vaes,+vpclmulqdq,+vzeroupper,-waitpkg,+wbnoinvd,-widekl,+x87,-xop,+xsave,+xsavec,+xsaveopt,+xsaves" }

[nix-shell:~/src/zig/build-llvm18-release]$ ~/local/llvm18-assert/bin/clang -c reduced.ll -O3
clang: /home/andy/dev/llvm-project-18/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:991: void {anonymous}::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*): Assertion `(TLI.getTypeAction(*DAG.getContext(), Op.getValueType()) == TargetLowering::TypeLegal || Op.getOpcode() == ISD::TargetConstant || Op.getOpcode() == ISD::Register) && "Unexpected illegal type!"' failed.
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/andy/local/llvm18-assert/bin/clang -c reduced.ll -O3
1.      Code generation
2.      Running pass 'Function Pass Manager' on module 'reduced.ll'.
3.      Running pass 'X86 DAG->DAG Instruction Selection' on function '@"fmt.parse_float.decimal.Decimal(f16).leftShift"'
 #<!-- -->0 0x000000000387f4db llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) (/home/andy/local/llvm18-assert/bin/clang+0x387f4db)
 #<!-- -->1 0x000000000387c83b llvm::sys::RunSignalHandlers() (/home/andy/local/llvm18-assert/bin/clang+0x387c83b)
 #<!-- -->2 0x00000000037c1508 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #<!-- -->3 0x00007f2075454a70 __restore_rt (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x3da70)
 #<!-- -->4 0x00007f20754a3ddc __pthread_kill_implementation (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x8cddc)
 #<!-- -->5 0x00007f20754549c6 gsignal (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x3d9c6)
 #<!-- -->6 0x00007f207543d8fa abort (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x268fa)
 #<!-- -->7 0x00007f207543d819 _nl_load_domain.cold (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x26819)
 #<!-- -->8 0x00007f207544d3c6 (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x363c6)
 #<!-- -->9 0x00000000048a69fa (anonymous namespace)::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*) LegalizeDAG.cpp:0:0
#<!-- -->10 0x00000000048b3100 llvm::SelectionDAG::Legalize() (/home/andy/local/llvm18-assert/bin/clang+0x48b3100)
#<!-- -->11 0x000000000499c826 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/home/andy/local/llvm18-assert/bin/clang+0x499c826)
#<!-- -->12 0x00000000049a06ac llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&amp;) (/home/andy/local/llvm18-assert/bin/clang+0x49a06ac)
#<!-- -->13 0x00000000049a2257 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&amp;) (.part.0) SelectionDAGISel.cpp:0:0
#<!-- -->14 0x0000000002409ff5 (anonymous namespace)::X86DAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&amp;) X86ISelDAGToDAG.cpp:0:0
#<!-- -->15 0x0000000002c30325 llvm::MachineFunctionPass::runOnFunction(llvm::Function&amp;) (.part.0) MachineFunctionPass.cpp:0:0
#<!-- -->16 0x0000000003213619 llvm::FPPassManager::runOnFunction(llvm::Function&amp;) (/home/andy/local/llvm18-assert/bin/clang+0x3213619)
#<!-- -->17 0x0000000003213751 llvm::FPPassManager::runOnModule(llvm::Module&amp;) (/home/andy/local/llvm18-assert/bin/clang+0x3213751)
#<!-- -->18 0x0000000003214057 llvm::legacy::PassManagerImpl::run(llvm::Module&amp;) (/home/andy/local/llvm18-assert/bin/clang+0x3214057)
#<!-- -->19 0x0000000003aedb33 clang::EmitBackendOutput(clang::DiagnosticsEngine&amp;, clang::HeaderSearchOptions const&amp;, clang::CodeGenOptions const&amp;, clang::TargetOptions const&amp;, clang::LangOptions const&amp;, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr&lt;llvm::vfs::FileSystem&gt;, std::unique_ptr&lt;llvm::raw_pwrite_stream, std::default_delete&lt;llvm::raw_pwrite_stream&gt;&gt;, clang::BackendConsumer*) (/home/andy/local/llvm18-assert/bin/clang+0x3aedb33)
#<!-- -->20 0x00000000040cd0fa clang::CodeGenAction::ExecuteAction() (/home/andy/local/llvm18-assert/bin/clang+0x40cd0fa)
#<!-- -->21 0x000000000434b2c9 clang::FrontendAction::Execute() (/home/andy/local/llvm18-assert/bin/clang+0x434b2c9)
#<!-- -->22 0x00000000042d0c02 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&amp;) (/home/andy/local/llvm18-assert/bin/clang+0x42d0c02)
#<!-- -->23 0x000000000441906f clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/andy/local/llvm18-assert/bin/clang+0x441906f)
#<!-- -->24 0x0000000000b7b6ca cc1_main(llvm::ArrayRef&lt;char const*&gt;, char const*, void*) (/home/andy/local/llvm18-assert/bin/clang+0xb7b6ca)
#<!-- -->25 0x0000000000b736a7 ExecuteCC1Tool(llvm::SmallVectorImpl&lt;char const*&gt;&amp;, llvm::ToolContext const&amp;) driver.cpp:0:0
#<!-- -->26 0x000000000410e509 void llvm::function_ref&lt;void ()&gt;::callback_fn&lt;clang::driver::CC1Command::Execute(llvm::ArrayRef&lt;std::optional&lt;llvm::StringRef&gt;&gt;, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt;&gt;*, bool*) const::'lambda'()&gt;(long) Job.cpp:0:0
#<!-- -->27 0x00000000037c1962 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref&lt;void ()&gt;) (/home/andy/local/llvm18-assert/bin/clang+0x37c1962)
#<!-- -->28 0x000000000410fbf4 clang::driver::CC1Command::Execute(llvm::ArrayRef&lt;std::optional&lt;llvm::StringRef&gt;&gt;, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt;&gt;*, bool*) const (.part.0) Job.cpp:0:0
#<!-- -->29 0x00000000040d6ae5 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&amp;, clang::driver::Command const*&amp;, bool) const (/home/andy/local/llvm18-assert/bin/clang+0x40d6ae5)
#<!-- -->30 0x00000000040d75dd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt;&gt;&amp;, bool) const (/home/andy/local/llvm18-assert/bin/clang+0x40d75dd)
#<!-- -->31 0x00000000040e1bb4 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt;&gt;&amp;) (/home/andy/local/llvm18-assert/bin/clang+0x40e1bb4)
#<!-- -->32 0x0000000000b78d69 clang_main(int, char**, llvm::ToolContext const&amp;) (/home/andy/local/llvm18-assert/bin/clang+0xb78d69)
#<!-- -->33 0x0000000000a6feb3 main (/home/andy/local/llvm18-assert/bin/clang+0xa6feb3)
#<!-- -->34 0x00007f207543efce __libc_start_call_main (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x27fce)
#<!-- -->35 0x00007f207543f089 __libc_start_main@<!-- -->GLIBC_2.2.5 (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x28089)
#<!-- -->36 0x0000000000b72315 _start (/home/andy/local/llvm18-assert/bin/clang+0xb72315)
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
clang version 18.1.5 (https://github.com/llvm/llvm-project 78b99c73ee4b96fe9ce0e294d4632326afb2db42)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/andy/local/llvm18-assert/bin
clang: note: diagnostic msg: Error generating preprocessed source(s) - no preprocessable inputs.

[andrewrk]

Another reduction of the same assertion found by @mikdusan:

; ModuleID = 'reduced.bc'
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

define fastcc void @aro.Parser.eatIdentifier(<16 x i1> %0) #0 {
Entry:
  %1 = shufflevector <16 x i1> %0, <16 x i1> zeroinitializer, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 28, i32 29, i32 30, i32 31>
  %2 = bitcast <16 x i1> %1 to i16
  %3 = icmp ne i16 %2, 0
  br i1 %3, label %Then21.i, label %Else.i131.i

Else.i131.i:                                      ; preds = %Entry
  %4 = icmp eq i21 0, 0
  br label %Then21.i

Then21.i:                                         ; preds = %Else.i131.i, %Entry
  ret void
}

attributes #0 = { "target-features"="-16bit-mode,-32bit-mode,-3dnow,-3dnowa,+64bit,+adx,+aes,+allow-light-256-bit,-amx-bf16,-amx-complex,-amx-fp16,-amx-int8,-amx-tile,+avx,-avx10.1-256,-avx10.1-512,+avx2,+avx512bf16,+avx512bitalg,+avx512bw,+avx512cd,+avx512dq,-avx512er,+avx512f,-avx512fp16,+avx512ifma,-avx512pf,+avx512vbmi,+avx512vbmi2,+avx512vl,+avx512vnni,-avx512vp2intersect,+avx512vpopcntdq,-avxifma,-avxneconvert,-avxvnni,-avxvnniint16,-avxvnniint8,+bmi,+bmi2,+branchfusion,-ccmp,-cf,-cldemote,+clflushopt,+clwb,+clzero,+cmov,-cmpccxadd,+crc32,+cx16,+cx8,-egpr,-enqcmd,-ermsb,-evex512,+f16c,-false-deps-getmant,-false-deps-lzcnt-tzcnt,-false-deps-mulc,-false-deps-mullq,-false-deps-perm,-false-deps-popcnt,-false-deps-range,-fast-11bytenop,+fast-15bytenop,-fast-7bytenop,+fast-bextr,-fast-gather,-fast-hops,+fast-lzcnt,+fast-movbe,+fast-scalar-fsqrt,+fast-scalar-shift-masks,-fast-shld-rotate,-fast-variable-crosslane-shuffle,+fast-variable-perlane-shuffle,+fast-vector-fsqrt,-fast-vector-shift-masks,-faster-shift-than-shuffle,+fma,-fma4,+fsgsbase,+fsrm,+fxsr,+gfni,-harden-sls-ijmp,-harden-sls-ret,-hreset,-idivl-to-divb,-idivq-to-divl,+invpcid,-kl,-lea-sp,-lea-uses-ag,-lvi-cfi,-lvi-load-hardening,-lwp,+lzcnt,+macrofusion,+mmx,+movbe,-movdir64b,-movdiri,-mwaitx,-ndd,-no-bypass-delay,-no-bypass-delay-blend,-no-bypass-delay-mov,-no-bypass-delay-shuffle,+nopl,-pad-short-functions,+pclmul,-pconfig,+pku,+popcnt,-ppx,-prefer-128-bit,-prefer-256-bit,-prefer-mask-registers,-prefer-movmsk-over-vtest,-prefer-no-gather,-prefer-no-scatter,-prefetchi,-prefetchwt1,+prfchw,-ptwrite,-push2pop2,-raoint,+rdpid,+rdpru,+rdrnd,+rdseed,-retpoline,-retpoline-external-thunk,-retpoline-indirect-branches,-retpoline-indirect-calls,-rtm,+sahf,+sbb-dep-breaking,-serialize,-seses,-sgx,+sha,-sha512,-shstk,-slow-3ops-lea,-slow-incdec,-slow-lea,-slow-pmaddwd,-slow-pmulld,+slow-shld,-slow-two-mem-ops,-slow-unaligned-mem-16,-slow-unaligned-mem-32,-sm3,-sm4,-soft-float,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+sse4a,-sse-unaligned-mem,+ssse3,-tagged-globals,-tbm,-tsxldtrk,-tuning-fast-imm-vector-shift,-uintr,-use-glm-div-sqrt-costs,-use-slm-arith-costs,-usermsr,+vaes,+vpclmulqdq,+vzeroupper,-waitpkg,+wbnoinvd,-widekl,+x87,-xop,+xsave,+xsavec,+xsaveopt,+xsaves" }

[nix-shell:~/src/zig/build-llvm18-release]$ ~/local/llvm18-assert/bin/llc ~/Downloads/reduced.ll 
llc: /home/andy/dev/llvm-project-18/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:991: void {anonymous}::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*): Assertion `(TLI.getTypeAction(*DAG.getContext(), Op.getValueType()) == TargetLowering::TypeLegal || Op.getOpcode() == ISD::TargetConstant || Op.getOpcode() == ISD::Register) && "Unexpected illegal type!"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.      Program arguments: /home/andy/local/llvm18-assert/bin/llc /home/andy/Downloads/reduced.ll
1.      Running pass 'Function Pass Manager' on module '/home/andy/Downloads/reduced.ll'.
2.      Running pass 'X86 DAG->DAG Instruction Selection' on function '@aro.Parser.eatIdentifier'
 #0 0x000000000393ec9b llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/andy/local/llvm18-assert/bin/llc+0x393ec9b)
 #1 0x000000000393bffb llvm::sys::RunSignalHandlers() (/home/andy/local/llvm18-assert/bin/llc+0x393bffb)
 #2 0x000000000393c125 SignalHandler(int) Signals.cpp:0:0
 #3 0x00007f19a7d74a70 __restore_rt (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x3da70)
 #4 0x00007f19a7dc3ddc __pthread_kill_implementation (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x8cddc)
 #5 0x00007f19a7d749c6 gsignal (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x3d9c6)
 #6 0x00007f19a7d5d8fa abort (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x268fa)
 #7 0x00007f19a7d5d819 _nl_load_domain.cold (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x26819)
 #8 0x00007f19a7d6d3c6 (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x363c6)
 #9 0x00000000035dcc6a (anonymous namespace)::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*) LegalizeDAG.cpp:0:0
#10 0x00000000035e9370 llvm::SelectionDAG::Legalize() (/home/andy/local/llvm18-assert/bin/llc+0x35e9370)
#11 0x00000000036f86f6 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/home/andy/local/llvm18-assert/bin/llc+0x36f86f6)
#12 0x00000000036fc57c llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&) (/home/andy/local/llvm18-assert/bin/llc+0x36fc57c)
#13 0x00000000036fe127 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&) (.part.0) SelectionDAGISel.cpp:0:0
#14 0x0000000001dd4985 (anonymous namespace)::X86DAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&) X86ISelDAGToDAG.cpp:0:0
#15 0x000000000292dd25 llvm::MachineFunctionPass::runOnFunction(llvm::Function&) (.part.0) MachineFunctionPass.cpp:0:0
#16 0x0000000002ef1789 llvm::FPPassManager::runOnFunction(llvm::Function&) (/home/andy/local/llvm18-assert/bin/llc+0x2ef1789)
#17 0x0000000002ef18c1 llvm::FPPassManager::runOnModule(llvm::Module&) (/home/andy/local/llvm18-assert/bin/llc+0x2ef18c1)
#18 0x0000000002ef21c7 llvm::legacy::PassManagerImpl::run(llvm::Module&) (/home/andy/local/llvm18-assert/bin/llc+0x2ef21c7)
#19 0x00000000007fe10b compileModule(char**, llvm::LLVMContext&) llc.cpp:0:0
#20 0x00000000007049a7 main (/home/andy/local/llvm18-assert/bin/llc+0x7049a7)
#21 0x00007f19a7d5efce __libc_start_call_main (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x27fce)
#22 0x00007f19a7d5f089 __libc_start_main@GLIBC_2.2.5 (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x28089)
#23 0x00000000007f3c25 _start (/home/andy/local/llvm18-assert/bin/llc+0x7f3c25)
Aborted (core dumped)

[llvmbot]

@llvm/issue-subscribers-backend-x86

Author: Andrew Kelley (andrewrk)

version: LLVM 18.x branch (commit 78b99c7)

The Zig compiler fails to build from source after updating to LLVM 18.

reduced.ll:

target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

define fastcc void @"fmt.parse_float.decimal.Decimal(f16).leftShift"() #<!-- -->0 {
  br label %1

1:                                                ; preds = %7, %2, %0
  %.sroa.02.0 = phi i64 [ 0, %0 ], [ -1, %7 ], [ %4, %2 ]
  %.sroa.0.0 = phi i64 [ 1, %0 ], [ %3, %7 ], [ %3, %2 ]
  %.not = icmp eq i64 %.sroa.0.0, 0
  br i1 %.not, label %6, label %2

2:                                                ; preds = %1
  %3 = add i64 %.sroa.0.0, 1
  %4 = add i64 %.sroa.02.0, -1
  %5 = icmp eq i64 %.sroa.02.0, 0
  br i1 %5, label %7, label %1

6:                                                ; preds = %1
  ret void

7:                                                ; preds = %2
  %8 = getelementptr [768 x i8], ptr null, i64 0, i64 %4
  store i8 0, ptr %8, align 1
  br label %1

; uselistorder directives
  uselistorder i64 %3, { 1, 0 }
}

attributes #<!-- -->0 = { "target-features"="-16bit-mode,-32bit-mode,-3dnow,-3dnowa,+64bit,+adx,+aes,+allow-light-256-bit,-amx-bf16,-amx-complex,-amx-fp16,-amx-int8,-amx-tile,+avx,-avx10.1-256,-avx10.1-512,+avx2,+avx512bf16,+avx512bitalg,+avx512bw,+avx512cd,+avx512dq,-avx512er,+avx512f,-avx512fp16,+avx512ifma,-avx512pf,+avx512vbmi,+avx512vbmi2,+avx512vl,+avx512vnni,-avx512vp2intersect,+avx512vpopcntdq,-avxifma,-avxneconvert,-avxvnni,-avxvnniint16,-avxvnniint8,+bmi,+bmi2,+branchfusion,-ccmp,-cf,-cldemote,+clflushopt,+clwb,+clzero,+cmov,-cmpccxadd,+crc32,+cx16,+cx8,-egpr,-enqcmd,-ermsb,-evex512,+f16c,-false-deps-getmant,-false-deps-lzcnt-tzcnt,-false-deps-mulc,-false-deps-mullq,-false-deps-perm,-false-deps-popcnt,-false-deps-range,-fast-11bytenop,+fast-15bytenop,-fast-7bytenop,+fast-bextr,-fast-gather,-fast-hops,+fast-lzcnt,+fast-movbe,+fast-scalar-fsqrt,+fast-scalar-shift-masks,-fast-shld-rotate,-fast-variable-crosslane-shuffle,+fast-variable-perlane-shuffle,+fast-vector-fsqrt,-fast-vector-shift-masks,-faster-shift-than-shuffle,+fma,-fma4,+fsgsbase,+fsrm,+fxsr,+gfni,-harden-sls-ijmp,-harden-sls-ret,-hreset,-idivl-to-divb,-idivq-to-divl,+invpcid,-kl,-lea-sp,-lea-uses-ag,-lvi-cfi,-lvi-load-hardening,-lwp,+lzcnt,+macrofusion,+mmx,+movbe,-movdir64b,-movdiri,+mwaitx,-ndd,-no-bypass-delay,-no-bypass-delay-blend,-no-bypass-delay-mov,-no-bypass-delay-shuffle,+nopl,-pad-short-functions,+pclmul,-pconfig,+pku,+popcnt,-ppx,-prefer-128-bit,-prefer-256-bit,-prefer-mask-registers,-prefer-movmsk-over-vtest,-prefer-no-gather,-prefer-no-scatter,-prefetchi,-prefetchwt1,+prfchw,-ptwrite,-push2pop2,-raoint,+rdpid,+rdpru,+rdrnd,+rdseed,-retpoline,-retpoline-external-thunk,-retpoline-indirect-branches,-retpoline-indirect-calls,-rtm,+sahf,+sbb-dep-breaking,-serialize,-seses,-sgx,+sha,-sha512,+shstk,-slow-3ops-lea,-slow-incdec,-slow-lea,-slow-pmaddwd,-slow-pmulld,+slow-shld,-slow-two-mem-ops,-slow-unaligned-mem-16,-slow-unaligned-mem-32,-sm3,-sm4,-soft-float,+sse,+sse2,+sse3,+sse4.1,+sse4.2,+sse4a,-sse-unaligned-mem,+ssse3,-tagged-globals,-tbm,-tsxldtrk,-tuning-fast-imm-vector-shift,-uintr,-use-glm-div-sqrt-costs,-use-slm-arith-costs,-usermsr,+vaes,+vpclmulqdq,+vzeroupper,-waitpkg,+wbnoinvd,-widekl,+x87,-xop,+xsave,+xsavec,+xsaveopt,+xsaves" }

[nix-shell:~/src/zig/build-llvm18-release]$ ~/local/llvm18-assert/bin/clang -c reduced.ll -O3
clang: /home/andy/dev/llvm-project-18/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp:991: void {anonymous}::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*): Assertion `(TLI.getTypeAction(*DAG.getContext(), Op.getValueType()) == TargetLowering::TypeLegal || Op.getOpcode() == ISD::TargetConstant || Op.getOpcode() == ISD::Register) && "Unexpected illegal type!"' failed.
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/andy/local/llvm18-assert/bin/clang -c reduced.ll -O3
1.      Code generation
2.      Running pass 'Function Pass Manager' on module 'reduced.ll'.
3.      Running pass 'X86 DAG->DAG Instruction Selection' on function '@"fmt.parse_float.decimal.Decimal(f16).leftShift"'
 #<!-- -->0 0x000000000387f4db llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) (/home/andy/local/llvm18-assert/bin/clang+0x387f4db)
 #<!-- -->1 0x000000000387c83b llvm::sys::RunSignalHandlers() (/home/andy/local/llvm18-assert/bin/clang+0x387c83b)
 #<!-- -->2 0x00000000037c1508 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #<!-- -->3 0x00007f2075454a70 __restore_rt (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x3da70)
 #<!-- -->4 0x00007f20754a3ddc __pthread_kill_implementation (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x8cddc)
 #<!-- -->5 0x00007f20754549c6 gsignal (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x3d9c6)
 #<!-- -->6 0x00007f207543d8fa abort (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x268fa)
 #<!-- -->7 0x00007f207543d819 _nl_load_domain.cold (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x26819)
 #<!-- -->8 0x00007f207544d3c6 (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x363c6)
 #<!-- -->9 0x00000000048a69fa (anonymous namespace)::SelectionDAGLegalize::LegalizeOp(llvm::SDNode*) LegalizeDAG.cpp:0:0
#<!-- -->10 0x00000000048b3100 llvm::SelectionDAG::Legalize() (/home/andy/local/llvm18-assert/bin/clang+0x48b3100)
#<!-- -->11 0x000000000499c826 llvm::SelectionDAGISel::CodeGenAndEmitDAG() (/home/andy/local/llvm18-assert/bin/clang+0x499c826)
#<!-- -->12 0x00000000049a06ac llvm::SelectionDAGISel::SelectAllBasicBlocks(llvm::Function const&amp;) (/home/andy/local/llvm18-assert/bin/clang+0x49a06ac)
#<!-- -->13 0x00000000049a2257 llvm::SelectionDAGISel::runOnMachineFunction(llvm::MachineFunction&amp;) (.part.0) SelectionDAGISel.cpp:0:0
#<!-- -->14 0x0000000002409ff5 (anonymous namespace)::X86DAGToDAGISel::runOnMachineFunction(llvm::MachineFunction&amp;) X86ISelDAGToDAG.cpp:0:0
#<!-- -->15 0x0000000002c30325 llvm::MachineFunctionPass::runOnFunction(llvm::Function&amp;) (.part.0) MachineFunctionPass.cpp:0:0
#<!-- -->16 0x0000000003213619 llvm::FPPassManager::runOnFunction(llvm::Function&amp;) (/home/andy/local/llvm18-assert/bin/clang+0x3213619)
#<!-- -->17 0x0000000003213751 llvm::FPPassManager::runOnModule(llvm::Module&amp;) (/home/andy/local/llvm18-assert/bin/clang+0x3213751)
#<!-- -->18 0x0000000003214057 llvm::legacy::PassManagerImpl::run(llvm::Module&amp;) (/home/andy/local/llvm18-assert/bin/clang+0x3214057)
#<!-- -->19 0x0000000003aedb33 clang::EmitBackendOutput(clang::DiagnosticsEngine&amp;, clang::HeaderSearchOptions const&amp;, clang::CodeGenOptions const&amp;, clang::TargetOptions const&amp;, clang::LangOptions const&amp;, llvm::StringRef, llvm::Module*, clang::BackendAction, llvm::IntrusiveRefCntPtr&lt;llvm::vfs::FileSystem&gt;, std::unique_ptr&lt;llvm::raw_pwrite_stream, std::default_delete&lt;llvm::raw_pwrite_stream&gt;&gt;, clang::BackendConsumer*) (/home/andy/local/llvm18-assert/bin/clang+0x3aedb33)
#<!-- -->20 0x00000000040cd0fa clang::CodeGenAction::ExecuteAction() (/home/andy/local/llvm18-assert/bin/clang+0x40cd0fa)
#<!-- -->21 0x000000000434b2c9 clang::FrontendAction::Execute() (/home/andy/local/llvm18-assert/bin/clang+0x434b2c9)
#<!-- -->22 0x00000000042d0c02 clang::CompilerInstance::ExecuteAction(clang::FrontendAction&amp;) (/home/andy/local/llvm18-assert/bin/clang+0x42d0c02)
#<!-- -->23 0x000000000441906f clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/home/andy/local/llvm18-assert/bin/clang+0x441906f)
#<!-- -->24 0x0000000000b7b6ca cc1_main(llvm::ArrayRef&lt;char const*&gt;, char const*, void*) (/home/andy/local/llvm18-assert/bin/clang+0xb7b6ca)
#<!-- -->25 0x0000000000b736a7 ExecuteCC1Tool(llvm::SmallVectorImpl&lt;char const*&gt;&amp;, llvm::ToolContext const&amp;) driver.cpp:0:0
#<!-- -->26 0x000000000410e509 void llvm::function_ref&lt;void ()&gt;::callback_fn&lt;clang::driver::CC1Command::Execute(llvm::ArrayRef&lt;std::optional&lt;llvm::StringRef&gt;&gt;, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt;&gt;*, bool*) const::'lambda'()&gt;(long) Job.cpp:0:0
#<!-- -->27 0x00000000037c1962 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref&lt;void ()&gt;) (/home/andy/local/llvm18-assert/bin/clang+0x37c1962)
#<!-- -->28 0x000000000410fbf4 clang::driver::CC1Command::Execute(llvm::ArrayRef&lt;std::optional&lt;llvm::StringRef&gt;&gt;, std::__cxx11::basic_string&lt;char, std::char_traits&lt;char&gt;, std::allocator&lt;char&gt;&gt;*, bool*) const (.part.0) Job.cpp:0:0
#<!-- -->29 0x00000000040d6ae5 clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&amp;, clang::driver::Command const*&amp;, bool) const (/home/andy/local/llvm18-assert/bin/clang+0x40d6ae5)
#<!-- -->30 0x00000000040d75dd clang::driver::Compilation::ExecuteJobs(clang::driver::JobList const&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt;&gt;&amp;, bool) const (/home/andy/local/llvm18-assert/bin/clang+0x40d75dd)
#<!-- -->31 0x00000000040e1bb4 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt;&gt;&amp;) (/home/andy/local/llvm18-assert/bin/clang+0x40e1bb4)
#<!-- -->32 0x0000000000b78d69 clang_main(int, char**, llvm::ToolContext const&amp;) (/home/andy/local/llvm18-assert/bin/clang+0xb78d69)
#<!-- -->33 0x0000000000a6feb3 main (/home/andy/local/llvm18-assert/bin/clang+0xa6feb3)
#<!-- -->34 0x00007f207543efce __libc_start_call_main (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x27fce)
#<!-- -->35 0x00007f207543f089 __libc_start_main@<!-- -->GLIBC_2.2.5 (/nix/store/anlf335xlh41yjhm114swi87406mq5pw-glibc-2.38-44/lib/libc.so.6+0x28089)
#<!-- -->36 0x0000000000b72315 _start (/home/andy/local/llvm18-assert/bin/clang+0xb72315)
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
clang version 18.1.5 (https://github.com/llvm/llvm-project 78b99c73ee4b96fe9ce0e294d4632326afb2db42)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/andy/local/llvm18-assert/bin
clang: note: diagnostic msg: Error generating preprocessed source(s) - no preprocessable inputs.

[topperc]

It looks like X86Subtarget::canExtendTo512BW() returns true when X86Subtarget::useAVX512Regs() returns false. That's not how it used to work. If X86Subtarget::canExtendTo512BW() returned true, X86Subtarget::useAVX512Regs() also needed to return true.

The change seems to be that X86Subtarget::useAVX512Regs() now checks X86Subtarget::hasEVEX512() which is false in this test. X86Subtarget::canExtendTo512BW() does not check X86Subtarget::hasEVEX512().

CC: @phoebewang

[phoebewang]

It looks like X86Subtarget::canExtendTo512BW() returns true when X86Subtarget::useAVX512Regs() returns false. That's not how it used to work. If X86Subtarget::canExtendTo512BW() returned true, X86Subtarget::useAVX512Regs() also needed to return true.

The change seems to be that X86Subtarget::useAVX512Regs() now checks X86Subtarget::hasEVEX512() which is false in this test. X86Subtarget::canExtendTo512BW() does not check X86Subtarget::hasEVEX512().

CC: @phoebewang

Thanks @topperc. This is a bug, should be solved by #90390