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Clang assertion failure in CastInst::Create() with "Invalid cast!" when generating code for function with builtin expression #144771

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#145497
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Clang assertion failure in CastInst::Create() with "Invalid cast!" when generating code for function with builtin expression#144771
Bug
#145497
Assignees
Fznamznon
Labels
clang:codegenIR generation bugs: mangling, exceptions, etc.confirmedVerified by a second partycrashPrefer [crash-on-valid] or [crash-on-invalid]generated by fuzzerregression:19Regression in 19 release
@kappnkappn

Description

@kappnkappn
kappnkappn
opened on Jun 18, 2025

Compiler explorer: https://godbolt.org/z/r55hMorrY
generated by fuzzer

Code:

int v;

__attribute__((noinline, noclone)) void bar(void) { v++; }

#define T(n, t1, t2, tr, v1, v2, vr, b, o)                                     \
  __attribute__((noinline, noclone)) tr t##n##_1##b(t1 x, t2 y) {              \
    tr r;                                                                      \
    if (__builtin_##b##_overflow(x, y, &r))                                    \
      bar();                                                                   \
    return r;                                                                  \
  }                                                                            \
                                                                               \
  __attribute__((noinline, noclone)) tr t##n##_3##b(t2 y) {                    \
    tr r;                                                                      \
    if (__builtin_##b##_overflow((v1), y, &r))                             \
      bar();                                                                   \
    return r;                                                                  \
  }                                                                            \
                                                                               \
  __attribute__((noinline, noclone)) tr t##n##_4##b(t1 x) {                    \
    t2 y = (v2);                                                               \
    tr r;                                                                      \
    if (__builtin_##b##_overflow(x, y, &r))                                    \
      bar();                                                                   \
    return r;                                                                  \
  }                                                                            \
                                                                                                                                                                                                                                                           

#define ST(n, t, v1, v2, vr, b, o) T(n, t, t, t, v1, v2, vr, b, o)

#define TESTS(type, min, max)                                                  \
  ST(171, unsigned type, max, 3, 3 * (unsigned type)max, U(u, mul), 1)         


#define U(s, op) op
TESTS(_BitInt(119), (-332306998946228968225951765070086143wb - 1),
      332306998946228968225951765070086143wb)

Stack trace:

clang: /root/llvm-project/llvm/lib/IR/Instructions.cpp:3033: static llvm::CastInst* llvm::CastInst::Create(llvm::Instruction::CastOps, llvm::Value*, llvm::Type*, const llvm::Twine&, llvm::InsertPosition): Assertion `castIsValid(op, S, Ty) && "Invalid cast!"' 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: /opt/compiler-explorer/clang-assertions-trunk/bin/clang -gdwarf-4 -g -o /app/output.s -fno-verbose-asm -c --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics <source>
1.	<source>:36:1 <Spelling=<source>:20:3>: current parser token '__attribute__'
2.	<source>:36:1 <Spelling=<scratch space>:11:1>: LLVM IR generation of declaration 't171_3mul'
3.	<source>:36:1 <Spelling=<scratch space>:11:1>: Generating code for declaration 't171_3mul'
 #0 0x0000000003fb0f48 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3fb0f48)
 #1 0x0000000003faebd4 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3faebd4)
 #2 0x0000000003ef3728 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #3 0x0000772769842520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007727698969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #5 0x0000772769842476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #6 0x00007727698287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #7 0x000077276982871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #8 0x0000772769839e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #9 0x00000000038b5c54 (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x38b5c54)
#10 0x0000000000ff09b5 llvm::IRBuilderBase::CreateTrunc(llvm::Value*, llvm::Type*, llvm::Twine const&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xff09b5)
#11 0x0000000004847ac3 clang::CodeGen::CodeGenFunction::EmitBuiltinExpr(clang::GlobalDecl, unsigned int, clang::CallExpr const*, clang::CodeGen::ReturnValueSlot) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4847ac3)
#12 0x000000000432050e clang::CodeGen::CodeGenFunction::EmitCallExpr(clang::CallExpr const*, clang::CodeGen::ReturnValueSlot, llvm::CallBase**) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x432050e)
#13 0x0000000004392df4 (anonymous namespace)::ScalarExprEmitter::VisitCallExpr(clang::CallExpr const*) CGExprScalar.cpp:0:0
#14 0x0000000004385c20 clang::StmtVisitorBase<std::add_pointer, (anonymous namespace)::ScalarExprEmitter, llvm::Value*>::Visit(clang::Stmt*) CGExprScalar.cpp:0:0
#15 0x000000000438bb9c clang::CodeGen::CodeGenFunction::EmitScalarExpr(clang::Expr const*, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x438bb9c)
#16 0x00000000042ef36d clang::CodeGen::CodeGenFunction::EvaluateExprAsBool(clang::Expr const*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x42ef36d)
#17 0x000000000450ab4c clang::CodeGen::CodeGenFunction::EmitBranchOnBoolExpr(clang::Expr const*, llvm::BasicBlock*, llvm::BasicBlock*, unsigned long, clang::Stmt::Likelihood, clang::Expr const*, clang::VarDecl const*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x450ab4c)
#18 0x000000000449f7b5 clang::CodeGen::CodeGenFunction::EmitIfStmt(clang::IfStmt const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x449f7b5)
#19 0x00000000044982ae clang::CodeGen::CodeGenFunction::EmitStmt(clang::Stmt const*, llvm::ArrayRef<clang::Attr const*>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x44982ae)
#20 0x00000000044a018c clang::CodeGen::CodeGenFunction::EmitCompoundStmtWithoutScope(clang::CompoundStmt const&, bool, clang::CodeGen::AggValueSlot) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x44a018c)
#21 0x000000000450640e clang::CodeGen::CodeGenFunction::EmitFunctionBody(clang::Stmt const*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x450640e)
#22 0x0000000004519714 clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4519714)
#23 0x0000000004583cad clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4583cad)
#24 0x000000000457eca4 clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x457eca4)
#25 0x000000000457f353 clang::CodeGen::CodeGenModule::EmitGlobal(clang::GlobalDecl) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x457f353)
#26 0x0000000004589ef3 clang::CodeGen::CodeGenModule::EmitTopLevelDecl(clang::Decl*) (.part.0) CodeGenModule.cpp:0:0
#27 0x000000000496e0f6 (anonymous namespace)::CodeGeneratorImpl::HandleTopLevelDecl(clang::DeclGroupRef) ModuleBuilder.cpp:0:0
#28 0x000000000495dbd4 clang::BackendConsumer::HandleTopLevelDecl(clang::DeclGroupRef) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x495dbd4)
#29 0x0000000006664364 clang::ParseAST(clang::Sema&, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x6664364)
#30 0x000000000496a288 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x496a288)
#31 0x0000000004c640f5 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4c640f5)
#32 0x0000000004be13fe clang::CompilerInstance::ExecuteAction(clang::FrontendAction&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4be13fe)
#33 0x0000000004d565e9 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4d565e9)
#34 0x0000000000d821df cc1_main(llvm::ArrayRef<char const*>, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xd821df)
#35 0x0000000000d78dea ExecuteCC1Tool(llvm::SmallVectorImpl<char const*>&, llvm::ToolContext const&) driver.cpp:0:0
#36 0x00000000049d0d99 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
#37 0x0000000003ef3bc4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref<void ()>) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3ef3bc4)
#38 0x00000000049d13af 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
#39 0x000000000499344d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&, clang::driver::Command const*&, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x499344d)
#40 0x00000000049944de 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+0x49944de)
#41 0x000000000499c1e5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&, llvm::SmallVectorImpl<std::pair<int, clang::driver::Command const*>>&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x499c1e5)
#42 0x0000000000d7e6ef clang_main(int, char**, llvm::ToolContext const&) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xd7e6ef)
#43 0x0000000000c3c994 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xc3c994)
#44 0x0000772769829d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#45 0x0000772769829e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#46 0x0000000000d78895 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xd78895)
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134

Activity

llvmbot
added
clangClang issues not falling into any other category
on Jun 18, 2025
EugeneZelenko
added
clang:codegenIR generation bugs: mangling, exceptions, etc.
crashPrefer [crash-on-valid] or [crash-on-invalid]
generated by fuzzer
and removed
clangClang issues not falling into any other category
on Jun 18, 2025
EugeneZelenko
added the
Bug
issue type on Jun 18, 2025
llvmbot

llvmbot commented on Jun 18, 2025

@llvmbot
llvmbot
on Jun 18, 2025
Member

@llvm/issue-subscribers-clang-codegen

Author: None (kappnkappn)

Compiler explorer: [https://godbolt.org/z/r55hMorrY](https://godbolt.org/z/r55hMorrY) generated by fuzzer

Code:

int v;

__attribute__((noinline, noclone)) void bar(void) { v++; }

#define T(n, t1, t2, tr, v1, v2, vr, b, o)                                     \
  __attribute__((noinline, noclone)) tr t##n##_1##b(t1 x, t2 y) {              \
    tr r;                                                                      \
    if (__builtin_##b##_overflow(x, y, &amp;r))                                    \
      bar();                                                                   \
    return r;                                                                  \
  }                                                                            \
                                                                               \
  __attribute__((noinline, noclone)) tr t##n##_3##b(t2 y) {                    \
    tr r;                                                                      \
    if (__builtin_##b##_overflow((v1), y, &amp;r))                             \
      bar();                                                                   \
    return r;                                                                  \
  }                                                                            \
                                                                               \
  __attribute__((noinline, noclone)) tr t##n##_4##b(t1 x) {                    \
    t2 y = (v2);                                                               \
    tr r;                                                                      \
    if (__builtin_##b##_overflow(x, y, &amp;r))                                    \
      bar();                                                                   \
    return r;                                                                  \
  }                                                                            \
                                                                                                                                                                                                                                                           

#define ST(n, t, v1, v2, vr, b, o) T(n, t, t, t, v1, v2, vr, b, o)

#define TESTS(type, min, max)                                                  \
  ST(171, unsigned type, max, 3, 3 * (unsigned type)max, U(u, mul), 1)         


#define U(s, op) op
TESTS(_BitInt(119), (-332306998946228968225951765070086143wb - 1),
      332306998946228968225951765070086143wb)

Stack trace:

clang: /root/llvm-project/llvm/lib/IR/Instructions.cpp:3033: static llvm::CastInst* llvm::CastInst::Create(llvm::Instruction::CastOps, llvm::Value*, llvm::Type*, const llvm::Twine&amp;, llvm::InsertPosition): Assertion `castIsValid(op, S, Ty) &amp;&amp; "Invalid cast!"' 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: /opt/compiler-explorer/clang-assertions-trunk/bin/clang -gdwarf-4 -g -o /app/output.s -fno-verbose-asm -c --gcc-toolchain=/opt/compiler-explorer/gcc-snapshot -fcolor-diagnostics -fno-crash-diagnostics &lt;source&gt;
1.	&lt;source&gt;:36:1 &lt;Spelling=&lt;source&gt;:20:3&gt;: current parser token '__attribute__'
2.	&lt;source&gt;:36:1 &lt;Spelling=&lt;scratch space&gt;:11:1&gt;: LLVM IR generation of declaration 't171_3mul'
3.	&lt;source&gt;:36:1 &lt;Spelling=&lt;scratch space&gt;:11:1&gt;: Generating code for declaration 't171_3mul'
 #<!-- -->0 0x0000000003fb0f48 llvm::sys::PrintStackTrace(llvm::raw_ostream&amp;, int) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3fb0f48)
 #<!-- -->1 0x0000000003faebd4 llvm::sys::CleanupOnSignal(unsigned long) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3faebd4)
 #<!-- -->2 0x0000000003ef3728 CrashRecoverySignalHandler(int) CrashRecoveryContext.cpp:0:0
 #<!-- -->3 0x0000772769842520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #<!-- -->4 0x00007727698969fc pthread_kill (/lib/x86_64-linux-gnu/libc.so.6+0x969fc)
 #<!-- -->5 0x0000772769842476 gsignal (/lib/x86_64-linux-gnu/libc.so.6+0x42476)
 #<!-- -->6 0x00007727698287f3 abort (/lib/x86_64-linux-gnu/libc.so.6+0x287f3)
 #<!-- -->7 0x000077276982871b (/lib/x86_64-linux-gnu/libc.so.6+0x2871b)
 #<!-- -->8 0x0000772769839e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
 #<!-- -->9 0x00000000038b5c54 (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x38b5c54)
#<!-- -->10 0x0000000000ff09b5 llvm::IRBuilderBase::CreateTrunc(llvm::Value*, llvm::Type*, llvm::Twine const&amp;, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xff09b5)
#<!-- -->11 0x0000000004847ac3 clang::CodeGen::CodeGenFunction::EmitBuiltinExpr(clang::GlobalDecl, unsigned int, clang::CallExpr const*, clang::CodeGen::ReturnValueSlot) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4847ac3)
#<!-- -->12 0x000000000432050e clang::CodeGen::CodeGenFunction::EmitCallExpr(clang::CallExpr const*, clang::CodeGen::ReturnValueSlot, llvm::CallBase**) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x432050e)
#<!-- -->13 0x0000000004392df4 (anonymous namespace)::ScalarExprEmitter::VisitCallExpr(clang::CallExpr const*) CGExprScalar.cpp:0:0
#<!-- -->14 0x0000000004385c20 clang::StmtVisitorBase&lt;std::add_pointer, (anonymous namespace)::ScalarExprEmitter, llvm::Value*&gt;::Visit(clang::Stmt*) CGExprScalar.cpp:0:0
#<!-- -->15 0x000000000438bb9c clang::CodeGen::CodeGenFunction::EmitScalarExpr(clang::Expr const*, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x438bb9c)
#<!-- -->16 0x00000000042ef36d clang::CodeGen::CodeGenFunction::EvaluateExprAsBool(clang::Expr const*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x42ef36d)
#<!-- -->17 0x000000000450ab4c clang::CodeGen::CodeGenFunction::EmitBranchOnBoolExpr(clang::Expr const*, llvm::BasicBlock*, llvm::BasicBlock*, unsigned long, clang::Stmt::Likelihood, clang::Expr const*, clang::VarDecl const*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x450ab4c)
#<!-- -->18 0x000000000449f7b5 clang::CodeGen::CodeGenFunction::EmitIfStmt(clang::IfStmt const&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x449f7b5)
#<!-- -->19 0x00000000044982ae clang::CodeGen::CodeGenFunction::EmitStmt(clang::Stmt const*, llvm::ArrayRef&lt;clang::Attr const*&gt;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x44982ae)
#<!-- -->20 0x00000000044a018c clang::CodeGen::CodeGenFunction::EmitCompoundStmtWithoutScope(clang::CompoundStmt const&amp;, bool, clang::CodeGen::AggValueSlot) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x44a018c)
#<!-- -->21 0x000000000450640e clang::CodeGen::CodeGenFunction::EmitFunctionBody(clang::Stmt const*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x450640e)
#<!-- -->22 0x0000000004519714 clang::CodeGen::CodeGenFunction::GenerateCode(clang::GlobalDecl, llvm::Function*, clang::CodeGen::CGFunctionInfo const&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4519714)
#<!-- -->23 0x0000000004583cad clang::CodeGen::CodeGenModule::EmitGlobalFunctionDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4583cad)
#<!-- -->24 0x000000000457eca4 clang::CodeGen::CodeGenModule::EmitGlobalDefinition(clang::GlobalDecl, llvm::GlobalValue*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x457eca4)
#<!-- -->25 0x000000000457f353 clang::CodeGen::CodeGenModule::EmitGlobal(clang::GlobalDecl) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x457f353)
#<!-- -->26 0x0000000004589ef3 clang::CodeGen::CodeGenModule::EmitTopLevelDecl(clang::Decl*) (.part.0) CodeGenModule.cpp:0:0
#<!-- -->27 0x000000000496e0f6 (anonymous namespace)::CodeGeneratorImpl::HandleTopLevelDecl(clang::DeclGroupRef) ModuleBuilder.cpp:0:0
#<!-- -->28 0x000000000495dbd4 clang::BackendConsumer::HandleTopLevelDecl(clang::DeclGroupRef) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x495dbd4)
#<!-- -->29 0x0000000006664364 clang::ParseAST(clang::Sema&amp;, bool, bool) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x6664364)
#<!-- -->30 0x000000000496a288 clang::CodeGenAction::ExecuteAction() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x496a288)
#<!-- -->31 0x0000000004c640f5 clang::FrontendAction::Execute() (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4c640f5)
#<!-- -->32 0x0000000004be13fe clang::CompilerInstance::ExecuteAction(clang::FrontendAction&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4be13fe)
#<!-- -->33 0x0000000004d565e9 clang::ExecuteCompilerInvocation(clang::CompilerInstance*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x4d565e9)
#<!-- -->34 0x0000000000d821df cc1_main(llvm::ArrayRef&lt;char const*&gt;, char const*, void*) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xd821df)
#<!-- -->35 0x0000000000d78dea ExecuteCC1Tool(llvm::SmallVectorImpl&lt;char const*&gt;&amp;, llvm::ToolContext const&amp;) driver.cpp:0:0
#<!-- -->36 0x00000000049d0d99 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
#<!-- -->37 0x0000000003ef3bc4 llvm::CrashRecoveryContext::RunSafely(llvm::function_ref&lt;void ()&gt;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x3ef3bc4)
#<!-- -->38 0x00000000049d13af 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
#<!-- -->39 0x000000000499344d clang::driver::Compilation::ExecuteCommand(clang::driver::Command const&amp;, clang::driver::Command const*&amp;, bool) const (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x499344d)
#<!-- -->40 0x00000000049944de 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 (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x49944de)
#<!-- -->41 0x000000000499c1e5 clang::driver::Driver::ExecuteCompilation(clang::driver::Compilation&amp;, llvm::SmallVectorImpl&lt;std::pair&lt;int, clang::driver::Command const*&gt;&gt;&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0x499c1e5)
#<!-- -->42 0x0000000000d7e6ef clang_main(int, char**, llvm::ToolContext const&amp;) (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xd7e6ef)
#<!-- -->43 0x0000000000c3c994 main (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xc3c994)
#<!-- -->44 0x0000772769829d90 (/lib/x86_64-linux-gnu/libc.so.6+0x29d90)
#<!-- -->45 0x0000772769829e40 __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x29e40)
#<!-- -->46 0x0000000000d78895 _start (/opt/compiler-explorer/clang-assertions-trunk/bin/clang+0xd78895)
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Compiler returned: 134
shafik

shafik commented on Jun 18, 2025

@shafik
shafik
on Jun 18, 2025 · edited by shafik
Collaborator

A couple of tips, we like to know how far back the bug goes, since godbolt does not have assertion build for C going back you can use C++ w/ -x c, although sometimes the same code crashes in both C and C++.

Also no point is executing the code in the example if it crashes during complilation.

Looks like this started with clang-19: https://godbolt.org/z/cdxvq39TT

shafik
added
regression:19Regression in 19 release
on Jun 18, 2025
shafik

shafik commented on Jun 19, 2025

@shafik
shafik
on Jun 19, 2025
Collaborator

@Fznamznon @rjmccall git bisect points to 9ad72df

Fznamznon

Fznamznon commented on Jun 23, 2025

@Fznamznon
Fznamznon
on Jun 23, 2025 · edited by Fznamznon
Contributor

Reduced


void foo (unsigned _BitInt(119) y) {
    unsigned _BitInt(119) r; 

  __builtin_mul_overflow((332306998946228968225951765070086143wb), y, &r);
}
Fznamznon
self-assigned this
on Jun 23, 2025
AaronBallman
added
confirmedVerified by a second party
on Jun 23, 2025
Fznamznon
added a commit that references this issue on Jun 24, 2025

[clang] Fix __builtin_mul_overflow for big _BitInts

8397b94
Fznamznon
mentioned this on Jun 24, 2025

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clang:codegenIR generation bugs: mangling, exceptions, etc.confirmedVerified by a second partycrashPrefer [crash-on-valid] or [crash-on-invalid]generated by fuzzerregression:19Regression in 19 release

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      Clang assertion failure in CastInst::Create() with "Invalid cast!" when generating code for function with builtin expression · Issue #144771 · llvm/llvm-project