[clang] [OpenMP] Restore loop variable values after loop-tranformation constructs. (PR #208533)

Wed Jul 29 07:59:24 PDT 2026

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `amdgpu-clang-flang` running on `AMD-bb-w-05` while building `clang` at step 3 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/234/builds/988

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

```
Step 3 (annotate) failure: 'python ../llvm.src/offload/ci/openmp-offload-amdgpu-clang-flang.py ...' (failure)
...
PASS: libomp :: transform/split/zero_first_segment.c (382 of 502)
PASS: libomp :: parallel/omp_parallel_reduction.c (383 of 502)
PASS: libomp :: tasking/kmp_taskloop_5.c (384 of 502)
PASS: libomp :: tasking/omp50_taskwait_depend.c (385 of 502)
PASS: libomp :: tasking/kmp_detach_tasks_t2.c (386 of 502)
PASS: libomp :: transform/tile/intfor.c (387 of 502)
PASS: libomp :: transform/tile/negtile_intfor.c (388 of 502)
PASS: libomp :: transform/split/foreach.cpp (389 of 502)
PASS: libomp :: transform/unroll/factor_intfor.c (390 of 502)
PASS: libomp :: tasking/kmp_detach_tasks_t1.c (391 of 502)
FAIL: libomp :: transform/fuse/iterfor.cpp (392 of 502)
******************** TEST 'libomp :: transform/fuse/iterfor.cpp' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/./bin/clang++ -fopenmp   -I /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -I /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test -L /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/src  -fno-omit-frame-pointer -I /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/ompt -std=c++20 /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/transform/fuse/iterfor.cpp -o /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/transform/fuse/Output/iterfor.cpp.tmp -lm -latomic && /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/transform/fuse/Output/iterfor.cpp.tmp | tee /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/transform/fuse/Output/iterfor.cpp.tmp.out | /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/./bin/FileCheck /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/transform/fuse/iterfor.cpp --match-full-lines
# executed command: /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/./bin/clang++ -fopenmp -I /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -I /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test -L /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -fno-omit-frame-pointer -I /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/ompt -std=c++20 /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/transform/fuse/iterfor.cpp -o /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/transform/fuse/Output/iterfor.cpp.tmp -lm -latomic
# note: command had no output on stdout or stderr
# executed command: /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/transform/fuse/Output/iterfor.cpp.tmp
# note: command had no output on stdout or stderr
# executed command: tee /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/transform/fuse/Output/iterfor.cpp.tmp.out
# note: command had no output on stdout or stderr
# executed command: /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/./bin/FileCheck /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/transform/fuse/iterfor.cpp --match-full-lines
# .---command stderr------------
# | /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/transform/fuse/iterfor.cpp:186:16: error: CHECK-NEXT: is not on the line after the previous match
# | // CHECK-NEXT: [D] iterator dtor
# |                ^
# | <stdin>:48:1: note: 'next' match was here
# | [D] iterator dtor
# | ^
# | <stdin>:41:18: note: previous match ended here
# | [D] iterator dtor
# |                  ^
# | <stdin>:42:1: note: non-matching line after previous match is here
# | [C] iterator distance: 3
# | ^
# | 
# | Input file: <stdin>
# | Check file: /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/transform/fuse/iterfor.cpp
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             .
# |             .
# |             .
Step 8 (test-openmp) failure: test-openmp (failure)
...
PASS: libomp :: transform/split/zero_first_segment.c (382 of 502)
PASS: libomp :: parallel/omp_parallel_reduction.c (383 of 502)
PASS: libomp :: tasking/kmp_taskloop_5.c (384 of 502)
PASS: libomp :: tasking/omp50_taskwait_depend.c (385 of 502)
PASS: libomp :: tasking/kmp_detach_tasks_t2.c (386 of 502)
PASS: libomp :: transform/tile/intfor.c (387 of 502)
PASS: libomp :: transform/tile/negtile_intfor.c (388 of 502)
PASS: libomp :: transform/split/foreach.cpp (389 of 502)
PASS: libomp :: transform/unroll/factor_intfor.c (390 of 502)
PASS: libomp :: tasking/kmp_detach_tasks_t1.c (391 of 502)
FAIL: libomp :: transform/fuse/iterfor.cpp (392 of 502)
******************** TEST 'libomp :: transform/fuse/iterfor.cpp' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
/home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/./bin/clang++ -fopenmp   -I /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -I /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test -L /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/src  -fno-omit-frame-pointer -I /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/ompt -std=c++20 /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/transform/fuse/iterfor.cpp -o /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/transform/fuse/Output/iterfor.cpp.tmp -lm -latomic && /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/transform/fuse/Output/iterfor.cpp.tmp | tee /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/transform/fuse/Output/iterfor.cpp.tmp.out | /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/./bin/FileCheck /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/transform/fuse/iterfor.cpp --match-full-lines
# executed command: /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/./bin/clang++ -fopenmp -I /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -I /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test -L /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/src -fno-omit-frame-pointer -I /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/ompt -std=c++20 /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/transform/fuse/iterfor.cpp -o /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/transform/fuse/Output/iterfor.cpp.tmp -lm -latomic
# note: command had no output on stdout or stderr
# executed command: /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/transform/fuse/Output/iterfor.cpp.tmp
# note: command had no output on stdout or stderr
# executed command: tee /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/runtimes/runtimes-bins/openmp/runtime/test/transform/fuse/Output/iterfor.cpp.tmp.out
# note: command had no output on stdout or stderr
# executed command: /home/botworker/bbot/amdgpu-clang-flang/build/llvm.build/./bin/FileCheck /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/transform/fuse/iterfor.cpp --match-full-lines
# .---command stderr------------
# | /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/transform/fuse/iterfor.cpp:186:16: error: CHECK-NEXT: is not on the line after the previous match
# | // CHECK-NEXT: [D] iterator dtor
# |                ^
# | <stdin>:48:1: note: 'next' match was here
# | [D] iterator dtor
# | ^
# | <stdin>:41:18: note: previous match ended here
# | [D] iterator dtor
# |                  ^
# | <stdin>:42:1: note: non-matching line after previous match is here
# | [C] iterator distance: 3
# | ^
# | 
# | Input file: <stdin>
# | Check file: /home/botworker/bbot/amdgpu-clang-flang/llvm.src/openmp/runtime/test/transform/fuse/iterfor.cpp
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             .
# |             .
# |             .

```

</details>

https://github.com/llvm/llvm-project/pull/208533