[flang] ICE: not a typeless expr

[mathomp4]

We have encountered a bug in flang compilation. We aren't exactly sure what is happening, so I don't have a good description. The flang version is:

> flang --version
flang version 20.0.0git (git@github.com:GEOS-ESM/build-llvm-flang.git 697744d14fec6505d07f95249388ac2452ee5151)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin

so our flang is about 3 weeks old. I hope to have time next week to build the latest flang from main so maybe this is fixed, but I can't confirm this.

Traceback:

error: loc("/home/mathomp4/F90Files/flang-repro/reproducer.F90":12:7): not a typeless expr
LLVM ERROR: aborting
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang -fc1 -triple x86_64-unknown-linux-gnu -emit-obj -fcolor-diagnostics -mrelocation-model pic -pic-level 2 -pic-is-pie -target-cpu x86-64 -resource-dir /ford1/share/gmao_SIteam/llvm-flang/2024-10-22/lib/clang/20 -mframe-pointer=all -o reproducer.o -x f95-cpp-input reproducer.F90
 #0 0x000000000152e05b llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0x152e05b)
 #1 0x000000000152b77b SignalHandler(int) Signals.cpp:0:0
 #2 0x0000149a3cbfdd10 __restore_rt (/lib64/libpthread.so.0+0x12d10)
 #3 0x0000149a3b3a052f raise (/lib64/libc.so.6+0x4e52f)
 #4 0x0000149a3b373e65 abort (/lib64/libc.so.6+0x21e65)
 #5 0x0000000000f4b0be llvm::UniqueStringSaver::save(llvm::StringRef) (.cold) StringSaver.cpp:0:0
 #6 0x00000000014b933a (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0x14b933a)
 #7 0x0000000001d26cd3 (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0x1d26cd3)
 #8 0x0000000001f5a8a1 mlir::Type (anonymous namespace)::TypeBuilderImpl::genExprType<Fortran::evaluate::FunctionRef<Fortran::evaluate::Type<(Fortran::common::TypeCategory)3, 2>>>(Fortran::evaluate::FunctionRef<Fortran::evaluate::Type<(Fortran::common::TypeCategory)3, 2>> const&) ConvertType.cpp:0:0
 #9 0x0000000001f5ae3a Fortran::lower::TypeBuilder<Fortran::evaluate::Type<(Fortran::common::TypeCategory)3, 1>>::genType(Fortran::lower::AbstractConverter&, Fortran::evaluate::FunctionRef<Fortran::evaluate::Type<(Fortran::common::TypeCategory)3, 1>> const&) (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0x1f5ae3a)
#10 0x0000000001f47ab4 hlfir::EntityWithAttributes (anonymous namespace)::HlfirBuilder::gen<Fortran::evaluate::Type<(Fortran::common::TypeCategory)3, 1>>(Fortran::evaluate::Expr<Fortran::evaluate::Type<(Fortran::common::TypeCategory)3, 1>> const&) ConvertExprToHLFIR.cpp:0:0
#11 0x0000000001f42abe hlfir::EntityWithAttributes (anonymous namespace)::HlfirBuilder::gen<Fortran::evaluate::SomeKind<(Fortran::common::TypeCategory)3>>(Fortran::evaluate::Expr<Fortran::evaluate::SomeKind<(Fortran::common::TypeCategory)3>> const&) ConvertExprToHLFIR.cpp:0:0
#12 0x0000000001f50cf1 hlfir::EntityWithAttributes (anonymous namespace)::HlfirBuilder::gen<Fortran::evaluate::SomeType>(Fortran::evaluate::Expr<Fortran::evaluate::SomeType> const&) (.part.0) ConvertExprToHLFIR.cpp:0:0
#13 0x0000000001f51073 Fortran::lower::convertExprToHLFIR(mlir::Location, Fortran::lower::AbstractConverter&, Fortran::evaluate::Expr<Fortran::evaluate::SomeType> const&, Fortran::lower::SymMap&, Fortran::lower::StatementContext&) (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0x1f51073)
#14 0x0000000001d49903 (anonymous namespace)::FirConverter::genDataAssignment(Fortran::evaluate::Assignment const&, Fortran::evaluate::ProcedureRef const*) Bridge.cpp:0:0
#15 0x0000000001d6038a (anonymous namespace)::FirConverter::genAssignment(Fortran::evaluate::Assignment const&) Bridge.cpp:0:0
#16 0x0000000001d75f90 (anonymous namespace)::FirConverter::genFIR(Fortran::lower::pft::Evaluation&, bool) (.constprop.0) Bridge.cpp:0:0
#17 0x0000000001d7a68d (anonymous namespace)::FirConverter::lowerFunc(Fortran::lower::pft::FunctionLikeUnit&) Bridge.cpp:0:0
#18 0x0000000001d7c149 Fortran::lower::LoweringBridge::lower(Fortran::parser::Program const&, Fortran::semantics::SemanticsContext const&) (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0x1d7c149)
#19 0x0000000001cef409 Fortran::frontend::CodeGenAction::beginSourceFileAction() (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0x1cef409)
#20 0x000000000156a3f5 Fortran::frontend::FrontendAction::beginSourceFile(Fortran::frontend::CompilerInstance&, Fortran::frontend::FrontendInputFile const&) (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0x156a3f5)
#21 0x00000000015599fc Fortran::frontend::CompilerInstance::executeAction(Fortran::frontend::FrontendAction&) (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0x15599fc)
#22 0x000000000157258d Fortran::frontend::executeCompilerInvocation(Fortran::frontend::CompilerInstance*) (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0x157258d)
#23 0x0000000001071388 fc1_main(llvm::ArrayRef<char const*>, char const*) (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0x1071388)
#24 0x0000000000f93dd6 main (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0xf93dd6)
#25 0x0000149a3b38c7e5 __libc_start_main (/lib64/libc.so.6+0x3a7e5)
#26 0x000000000107035e _start (/ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin/flang+0x107035e)
flang-20: error: unable to execute command: Aborted (core dumped)
flang-20: error: flang frontend command failed due to signal (use -v to see invocation)
flang version 20.0.0git (git@github.com:GEOS-ESM/build-llvm-flang.git 697744d14fec6505d07f95249388ac2452ee5151)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /ford1/share/gmao_SIteam/llvm-flang/2024-10-22/bin
flang-20: note: diagnostic msg:
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
flang-20: note: diagnostic msg: /home/mathomp4/tmpdir/HConfig-0c62c2
flang-20: note: diagnostic msg: /home/mathomp4/tmpdir/cutdown_module-3b0a59
flang-20: note: diagnostic msg: /home/mathomp4/tmpdir/reproducer-fb6cdb
flang-20: note: diagnostic msg: /home/mathomp4/tmpdir/HConfig-0c62c2.sh
flang-20: note: diagnostic msg:

********************

Per instructions here are the preprocessed source files (in a tarfile as it didn't like the separate ones):

files-from-flang-crash.tar.gz

We also have the original files which produced these if needed.

[mathomp4]

Since it had been a month and flang moves quick I rebuilt flang today and tried again, but sadly still fails. ☹

The version is:

> flang --version
flang version 20.0.0git (git@github.com:GEOS-ESM/build-llvm-flang.git 06721763152e9632932655490d1bb53d09902f42)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /ford1/share/gmao_SIteam/llvm-flang/2024-12-12/bin

[mathomp4]

@EugeneZelenko Is there anything I can do to help with this?

[EugeneZelenko]

@mathomp4: You should contact developers. I only help with issues management.

[mathomp4]

@mathomp4: You should contact developers. I only help with issues management.

Ah okay. I'd seen your name on the ticket and thought you might know. Thanks!

[mathomp4]

I can confirm that this bug is still in flang 21 as of yesterday.

[mathomp4]

Uh. This is weird. So, I just tried this again with flang as of yesterday using the files in this:

flang-reproducer.tar.gz

and:

> flang --version
flang version 21.0.0git (git@github.com:GEOS-ESM/build-llvm-flang.git 06721763152e9632932655490d1bb53d09902f42)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin
mathomp4 on discover33 in ~/F90Files/flang-repro with bash at 09:56:39 AM
> flang -c HConfig.F90 cutdown_module.F90 reproducer.F90
error: loc("/home/mathomp4/F90Files/flang-repro/reproducer.F90":12:7): not a typeless expr
LLVM ERROR: aborting
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace.
Stack dump:
0.	Program arguments: /gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang -fc1 -triple x86_64-unknown-linux-gnu -emit-obj -fcolor-diagnostics -mrelocation-model pic -pic-level 2 -pic-is-pie -target-cpu x86-64 -resource-dir /gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/lib/clang/21 -mframe-pointer=all -o reproducer.o -x f95 reproducer.F90
 #0 0x00000000018817ab llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang+0x18817ab)
 #1 0x000000000187e66f SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #2 0x000014ad77a2f910 __restore_rt (/lib64/libpthread.so.0+0x16910)
 #3 0x000014ad7733dd2b raise (/lib64/libc.so.6+0x4ad2b)
 #4 0x000014ad7733f3e5 abort (/lib64/libc.so.6+0x4c3e5)
 #5 0x0000000001184b64 llvm::UniqueStringSaver::save(llvm::StringRef) (.cold) StringSaver.cpp:0:0
 #6 0x0000000001802c8a (/gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang+0x1802c8a)
 #7 0x0000000001c6b8e3 (/gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang+0x1c6b8e3)
 #8 0x0000000001ed9611 mlir::Type (anonymous namespace)::TypeBuilderImpl::genExprType<Fortran::evaluate::FunctionRef<Fortran::evaluate::Type<(Fortran::common::TypeCategory)4, 2>>>(Fortran::evaluate::FunctionRef<Fortran::evaluate::Type<(Fortran::common::TypeCategory)4, 2>> const&) ConvertType.cpp:0:0
 #9 0x0000000001ed9bfa Fortran::lower::TypeBuilder<Fortran::evaluate::Type<(Fortran::common::TypeCategory)4, 1>>::genType(Fortran::lower::AbstractConverter&, Fortran::evaluate::FunctionRef<Fortran::evaluate::Type<(Fortran::common::TypeCategory)4, 1>> const&) (/gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang+0x1ed9bfa)
#10 0x0000000001ec3374 hlfir::EntityWithAttributes (anonymous namespace)::HlfirBuilder::gen<Fortran::evaluate::Type<(Fortran::common::TypeCategory)4, 1>>(Fortran::evaluate::Expr<Fortran::evaluate::Type<(Fortran::common::TypeCategory)4, 1>> const&) ConvertExprToHLFIR.cpp:0:0
#11 0x0000000001ebe906 hlfir::EntityWithAttributes (anonymous namespace)::HlfirBuilder::gen<Fortran::evaluate::SomeKind<(Fortran::common::TypeCategory)4>>(Fortran::evaluate::Expr<Fortran::evaluate::SomeKind<(Fortran::common::TypeCategory)4>> const&) ConvertExprToHLFIR.cpp:0:0
#12 0x0000000001ec5245 hlfir::EntityWithAttributes (anonymous namespace)::HlfirBuilder::gen<Fortran::evaluate::SomeType>(Fortran::evaluate::Expr<Fortran::evaluate::SomeType> const&) (.part.0) ConvertExprToHLFIR.cpp:0:0
#13 0x0000000001ec5a6d Fortran::lower::convertExprToHLFIR(mlir::Location, Fortran::lower::AbstractConverter&, Fortran::evaluate::Expr<Fortran::evaluate::SomeType> const&, Fortran::lower::SymMap&, Fortran::lower::StatementContext&) (/gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang+0x1ec5a6d)
#14 0x0000000001c8ae81 (anonymous namespace)::FirConverter::genDataAssignment(Fortran::evaluate::Assignment const&, Fortran::evaluate::ProcedureRef const*) Bridge.cpp:0:0
#15 0x0000000001c92cba (anonymous namespace)::FirConverter::genAssignment(Fortran::evaluate::Assignment const&) Bridge.cpp:0:0
#16 0x0000000001cafba0 (anonymous namespace)::FirConverter::genFIR(Fortran::lower::pft::Evaluation&, bool) (.constprop.0) Bridge.cpp:0:0
#17 0x0000000001cb34bc (anonymous namespace)::FirConverter::lowerFunc(Fortran::lower::pft::FunctionLikeUnit&) Bridge.cpp:0:0
#18 0x0000000001cb4a32 Fortran::lower::LoweringBridge::lower(Fortran::parser::Program const&, Fortran::semantics::SemanticsContext const&) (/gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang+0x1cb4a32)
#19 0x0000000001b88e83 Fortran::frontend::CodeGenAction::beginSourceFileAction() (/gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang+0x1b88e83)
#20 0x00000000018be17d Fortran::frontend::FrontendAction::beginSourceFile(Fortran::frontend::CompilerInstance&, Fortran::frontend::FrontendInputFile const&) (/gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang+0x18be17d)
#21 0x00000000018abdac Fortran::frontend::CompilerInstance::executeAction(Fortran::frontend::FrontendAction&) (/gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang+0x18abdac)
#22 0x00000000018c7ce4 Fortran::frontend::executeCompilerInvocation(Fortran::frontend::CompilerInstance*) (/gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang+0x18c7ce4)
#23 0x00000000012dbf9b fc1_main(llvm::ArrayRef<char const*>, char const*) (/gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang+0x12dbf9b)
#24 0x00000000011d4ba3 main (/gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin/flang+0x11d4ba3)
#25 0x000014ad7732824d __libc_start_main (/lib64/libc.so.6+0x3524d)
#26 0x00000000012da88a _start /home/abuild/rpmbuild/BUILD/glibc-2.31/csu/../sysdeps/x86_64/start.S:122:0
flang-21: error: unable to execute command: Aborted
flang-21: error: flang frontend command failed due to signal (use -v to see invocation)
flang version 21.0.0git (git@github.com:GEOS-ESM/build-llvm-flang.git 06721763152e9632932655490d1bb53d09902f42)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /gpfsm/dnb05/projects/p50/comp/SLES-15/llvm-flang/2025-07-10/bin
flang-21: note: diagnostic msg:
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
flang-21: note: diagnostic msg: /gpfsm/dnb34/tdirs/login/discover33.99760.mathomp4/HConfig-53941a
flang-21: note: diagnostic msg: /gpfsm/dnb34/tdirs/login/discover33.99760.mathomp4/cutdown_module-9a8cb1
flang-21: note: diagnostic msg: /gpfsm/dnb34/tdirs/login/discover33.99760.mathomp4/reproducer-6a05ca
flang-21: note: diagnostic msg: /gpfsm/dnb34/tdirs/login/discover33.99760.mathomp4/HConfig-53941a.sh
flang-21: note: diagnostic msg:

********************

Okay.

But, if I try out the files it asks me to attach, it works??

> mkdir FromICE
> cp /gpfsm/dnb34/tdirs/login/discover33.99760.mathomp4/HConfig-53941a  /gpfsm/dnb34/tdirs/login/discover33.99760.mathomp4/cutdown_module-9a8cb1 /gpfsm/dnb34/tdirs/login/discover33.99760.mathomp4/reproducer-6a05ca  /gpfsm/dnb34/tdirs/login/discover33.99760.mathomp4/HConfig-53941a.sh .
> sh HConfig-53941a.sh
> echo $?
0

[mathomp4]

Still fails with flang 21.1 from Homebrew:

❯ flang --version
Homebrew flang version 21.1.1
Target: arm64-apple-darwin24.6.0
Thread model: posix
InstalledDir: /opt/homebrew/Cellar/flang/21.1.1/libexec
Configuration file: /opt/homebrew/Cellar/flang/21.1.1/libexec/flang.cfg
Configuration file: /opt/homebrew/etc/clang/arm64-apple-darwin24.cfg
❯ ./doit.x
error: loc("/Users/fortran/flang-repro/reproducer.F90":12:7): not a typeless expr
LLVM ERROR: aborting
...