[flang-commits] [flang] [llvm] [flang][runtime] Replace recursion with iterative work queue (PR #137727)

Tue Jun 10 17:50:33 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `flang-runtime-cuda-gcc` running on `as-builder-7` while building `flang-rt,flang` at step 6 "build-flang-rt".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/152/builds/3153

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 6 (build-flang-rt) failure: cmake (failure)
...
11.265 [2/33/93] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/environment.cpp.o
11.563 [2/32/94] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/numeric.cpp.o
12.062 [2/31/95] Building CUDA object flang-rt/lib/runtime/CMakeFiles/obj.flang_rt.runtimePTX.dir/extrema.ptx
12.291 [2/30/96] Building CUDA object flang-rt/lib/runtime/CMakeFiles/obj.flang_rt.runtimePTX.dir/findloc.ptx
12.345 [2/29/97] Building CUDA object flang-rt/lib/runtime/CMakeFiles/obj.flang_rt.runtimePTX.dir/matmul-transpose.ptx
12.372 [2/28/98] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/work-queue.cpp.o
12.740 [2/27/99] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/external-unit.cpp.o
12.874 [2/26/100] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/transformational.cpp.o
12.897 [2/25/101] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/stop.cpp.o
13.358 [2/24/102] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/assign.cpp.o
FAILED: flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/assign.cpp.o 
ccache /usr/local/cuda/bin/nvcc -forward-unknown-to-host-compiler -ccbin=/usr/bin/g++ -DRT_USE_LIBCUDACXX=1 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/flang-rt/include -I/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/flang-rt/../flang/include -I/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/build/runtimes/runtimes-bins/flang-rt -I/home/buildbot/worker/third-party/nv/cccl/libcudacxx/include -G -g -O3 -DNDEBUG -std=c++17 "--generate-code=arch=compute_80,code=[compute_80,sm_80]" -fno-lto --no-exceptions -Xcompiler -fno-rtti -fno-unwind-tables -fno-asynchronous-unwind-tables -U_GLIBCXX_ASSERTIONS -U_LIBCPP_ENABLE_ASSERTIONS --expt-relaxed-constexpr -Xcudafe --diag_suppress=20208 -Xcudafe --display_error_number -MD -MT flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/assign.cpp.o -MF flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/assign.cpp.o.d -x cu -rdc=true -c /home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/flang-rt/lib/runtime/assign.cpp -o flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/assign.cpp.o
/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/flang-rt/lib/runtime/assign.cpp: In member function ‘int Fortran::runtime::DerivedAssignTicket<IS_COMPONENTWISE>::Begin(Fortran::runtime::WorkQueue&)’:
/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/flang-rt/lib/runtime/assign.cpp:534:41: error: ‘bool Fortran::runtime::Elementwise::IsComplete() const’ is protected within this context
  534 |       for (; !Elementwise::IsComplete(); Elementwise::Advance()) {
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~
/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/flang-rt/include/flang-rt/runtime/work-queue.h:106:6: note: declared protected here
  106 |   RT_API_ATTRS bool IsComplete() const { return elementAt_ >= elements_; }
      |      ^~~~~~~~~~
13.565 [2/23/103] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/derived.cpp.o
13.765 [2/22/104] Building CXX object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/reduce.cpp.o
13.788 [2/21/105] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/product.cpp.o
14.006 [2/20/106] Building CUDA object flang-rt/lib/runtime/CMakeFiles/obj.flang_rt.runtimePTX.dir/matmul.ptx
14.481 [2/19/107] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/edit-input.cpp.o
14.689 [2/18/108] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/sum.cpp.o
17.231 [2/17/109] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/reduction.cpp.o
18.066 [2/16/110] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/namelist.cpp.o
18.619 [2/15/111] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/format.cpp.o
19.453 [2/14/112] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/unit.cpp.o
19.798 [2/13/113] Building CUDA object flang-rt/lib/runtime/CMakeFiles/obj.flang_rt.runtimePTX.dir/dot-product.ptx
21.309 [2/12/114] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/edit-output.cpp.o
21.972 [2/11/115] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/io-api-minimal.cpp.o
22.993 [2/10/116] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/character.cpp.o
25.500 [2/9/117] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/descriptor-io.cpp.o
33.726 [2/8/118] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/io-api.cpp.o
37.037 [2/7/119] Building CUDA object flang-rt/lib/runtime/CMakeFiles/flang_rt.runtime.static.dir/io-stmt.cpp.o
/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/flang-rt/lib/runtime/io-stmt.cpp(964): warning #940-D: missing return statement at end of non-void function "Fortran::runtime::io::ChildIoStatementState<DIR>::mutableModes [with DIR=Fortran::runtime::io::Direction::Output]"
  }
  ^
          detected during instantiation of "Fortran::runtime::io::MutableModes &Fortran::runtime::io::ChildIoStatementState<DIR>::mutableModes() [with DIR=Fortran::runtime::io::Direction::Output]" at line 1094

Remark: The warnings can be suppressed with "-diag-suppress <warning-number>"

/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/flang-rt/lib/runtime/io-stmt.cpp(973): warning #940-D: missing return statement at end of non-void function "Fortran::runtime::io::ChildIoStatementState<DIR>::GetConnectionState [with DIR=Fortran::runtime::io::Direction::Output]"
  }
  ^
          detected during instantiation of "Fortran::runtime::io::ConnectionState &Fortran::runtime::io::ChildIoStatementState<DIR>::GetConnectionState() [with DIR=Fortran::runtime::io::Direction::Output]" at line 1094

/home/buildbot/worker/as-builder-7/flang-runtime-cuda-gcc/llvm-project/flang-rt/lib/runtime/io-stmt.cpp(982): warning #940-D: missing return statement at end of non-void function "Fortran::runtime::io::ChildIoStatementState<DIR>::GetExternalFileUnit [with DIR=Fortran::runtime::io::Direction::Output]"

```

</details>

https://github.com/llvm/llvm-project/pull/137727