[llvm] [TableGen] Introduce MatcherList to manage a linked list of Matchers. NFC (PR #177875)

Fri Feb 13 18:00:14 PST 2026

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `cross-project-tests-sie-ubuntu-dwarf5` running on `doug-worker-1b` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/163/builds/34544

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

```
Step 5 (build-unified-tree) failure: build (failure)
...
22.436 [386/8/42] Building X86GenMnemonicTables.inc...
22.905 [385/8/43] Building X86GenDisassemblerTables.inc...
23.360 [384/8/44] Building X86GenInstrMapping.inc...
27.004 [383/8/45] Building X86GenFoldTables.inc...
27.601 [382/8/46] Building X86GenPostLegalizeGICombiner.inc...
27.608 [381/8/47] Building Options.inc...
27.614 [378/8/48] Building Options.inc...
27.860 [375/8/49] Building Options.inc...
27.956 [270/8/50] Generating VCSVersion.inc
27.980 [269/8/51] Building X86GenDAGISel.inc...
FAILED: lib/Target/X86/X86GenDAGISel.inc /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/lib/Target/X86/X86GenDAGISel.inc 
cd /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/lib/Target/X86 && /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/bin/llvm-tblgen -gen-dag-isel -I/home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/llvm/lib/Target/X86 -I/home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/include -I/home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/llvm/include -I /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/llvm/lib/Target -omit-comments /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/llvm/lib/Target/X86/X86.td --write-if-changed -o /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/lib/Target/X86/X86GenDAGISel.inc
llvm-tblgen: /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/llvm/utils/TableGen/DAGISelMatcherOpt.cpp:486: void FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator): Assertion `!Optn == !Tmp && "Expected all to be null if any are null"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
Stack dump:
0.	Program arguments: /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/bin/llvm-tblgen -gen-dag-isel -I/home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/llvm/lib/Target/X86 -I/home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/include -I/home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/llvm/include -I /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/llvm/lib/Target -omit-comments /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/llvm-project/llvm/lib/Target/X86/X86.td --write-if-changed -o /home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/lib/Target/X86/X86GenDAGISel.inc
 #0 0x00005e61f60cb510 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/bin/llvm-tblgen+0x3ba510)
 #1 0x00005e61f60c83bf llvm::sys::RunSignalHandlers() (/home/buildbot/buildbot-root/cross-project-tests-sie-ubuntu-dwarf5/build/bin/llvm-tblgen+0x3b73bf)
 #2 0x00005e61f60c8512 SignalHandler(int, siginfo_t*, void*) Signals.cpp:0:0
 #3 0x00007ec12d15d520 (/lib/x86_64-linux-gnu/libc.so.6+0x42520)
 #4 0x00007ec12d1b19fc __pthread_kill_implementation ./nptl/pthread_kill.c:44:76
 #5 0x00007ec12d1b19fc __pthread_kill_internal ./nptl/pthread_kill.c:78:10
 #6 0x00007ec12d1b19fc pthread_kill ./nptl/pthread_kill.c:89:10
 #7 0x00007ec12d15d476 gsignal ./signal/../sysdeps/posix/raise.c:27:6
 #8 0x00007ec12d1437f3 abort ./stdlib/abort.c:81:7
 #9 0x00007ec12d14371b _nl_load_domain ./intl/loadmsgcat.c:1177:9
#10 0x00007ec12d154e96 (/lib/x86_64-linux-gnu/libc.so.6+0x39e96)
#11 0x00005e61f5f2b176 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#12 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#13 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#14 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#15 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#16 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#17 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#18 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#19 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#20 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#21 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#22 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#23 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#24 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#25 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#26 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#27 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#28 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#29 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#30 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#31 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0
#32 0x00005e61f5f2a387 FactorScope(llvm::MatcherList&, llvm::MatcherList::iterator_impl<false>) DAGISelMatcherOpt.cpp:0:0

```

</details>

https://github.com/llvm/llvm-project/pull/177875