| Issue |
139776
|
| Summary |
[flang][openacc] Flang hangs and continuously allocates memory when compiling gfortran test: goacc/loop-3.f95
|
| Labels |
flang
|
| Assignees |
|
| Reporter |
tarunprabhu
|
Steps to reproduce:
Assuming that the [LLVM test suite](https://github.com/llvm/llvm-test-suite) is checked out in `./llvm-test-suite`, compile the test as follows:
```
$ flang -fopenacc ./llvm-test-suite/Fortran/gfortran/regression/goacc/loop-3.f95
```
Observed behavior: Some warning messages are printed following which flang hangs and continuously allocates memory until either manually killed or an OOM error occurs. This was run with `/usr/bin/time -v` and terminated with `SIGTERM` after approx. 1 minute. The output in this case is provided below. Note the maximum resident set size and the number of page faults.
```
./llvm-test-suite/Fortran/gfortran/regression/goacc/loop-3.f95:18:9: warning: Misplaced OpenACC end directive
!$acc end loop ! { dg-error "Unexpected" }
^^^^^^^^
./llvm-test-suite/Fortran/gfortran/regression/goacc/loop-3.f95:25:9: warning: Misplaced OpenACC end directive
!$acc end loop ! { dg-error "Unexpected" }
^^^^^^^^
./llvm-test-suite/Fortran/gfortran/regression/goacc/loop-3.f95:32:9: warning: Misplaced OpenACC end directive
!$acc end loop ! { dg-error "Unexpected" }
^^^^^^^^
flang-21: error: unable to execute command: Terminated
flang-21: error: flang frontend command failed due to signal (use -v to see invocation)
flang version 21.0.0git (g...@github.com:llvm-project-tlp/llvm-project.git 84c1564d1825880d463d9f85153812f1f6805289)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /path/to/bin
Build config: +assertions
flang-21: note: diagnostic msg:
********************
PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
flang-21: note: diagnostic msg: /tmp/loop-3-2b0785
flang-21: note: diagnostic msg: /tmp/loop-3-2b0785.sh
flang-21: note: diagnostic msg:
********************
Command exited with non-zero status 254
Command being timed: "/path/to/bin/flang -fopenacc ./llvm-test-suite/Fortran/gfortran/regression/goacc/loop-3.f95"
User time (seconds): 18.04
System time (seconds): 53.96
Percent of CPU this job got: 99%
Elapsed (wall clock) time (h:mm:ss or m:ss): 1:12.41
Average shared text size (kbytes): 0
Average unshared data size (kbytes): 0
Average stack size (kbytes): 0
Average total size (kbytes): 0
Maximum resident set size (kbytes): 93215748
Average resident set size (kbytes): 0
Major (requiring I/O) page faults: 3
Minor (reclaiming a frame) page faults: 23283575
Voluntary context switches: 178
Involuntary context switches: 96
Swaps: 0
File system inputs: 0
File system outputs: 0
Socket messages sent: 0
Socket messages received: 0
Signals delivered: 0
Page size (bytes): 4096
Exit status: 254
```
What follows is a minimal section of code from the original test that seems to reproduce this behavior.
```fortran
subroutine test1
implicit none
integer :: i, j
outer_loop1: do i = 1, 5
!$acc loop
inner_loop1: do j = 1,5
if (i .eq. j) cycle outer_loop1 ! { dg-error "CYCLE statement" }
end do inner_loop1
end do outer_loop1
end subroutine test1
```
Another gfortran test, `goacc/loop-3-2.f95` also exhibits similar behavior.
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