[llvm] [VectorCombine] foldShuffleChainsToReduce - add support for partial vector reductions (PR #195119)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `bolt-aarch64-ubuntu-clang` running on `bolt-worker-aarch64` while building `llvm` at step 5 "build-clang-bolt".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/128/builds/13061

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

```
Step 5 (build-clang-bolt) failure: build (failure)
...
19.904 [8/2/3440] Linking CXX static library lib/libclangCodeGen.a
19.943 [7/2/3441] Linking CXX static library lib/libclangFrontendTool.a
20.054 [7/1/3442] Linking CXX executable bin/llvm-bolt
20.060 [2/5/3443] Building CXX object tools/clang/tools/driver/CMakeFiles/clang.dir/clang-driver.cpp.o
20.281 [2/4/3444] Building CXX object tools/clang/tools/driver/CMakeFiles/clang.dir/cc1gen_reproducer_main.cpp.o
20.328 [2/3/3445] Building CXX object tools/clang/tools/driver/CMakeFiles/clang.dir/cc1as_main.cpp.o
20.584 [2/2/3446] Building CXX object tools/clang/tools/driver/CMakeFiles/clang.dir/driver.cpp.o
20.712 [2/1/3447] Building CXX object tools/clang/tools/driver/CMakeFiles/clang.dir/cc1_main.cpp.o
21.575 [1/1/3448] Linking CXX executable bin/clang-23
158.954 [0/1/3449] Creating executable symlink bin/clang
FAILED: bin/clang 
/usr/bin/cmake -E cmake_symlink_executable bin/clang-23 bin/clang && cd /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/tools/clang/tools/driver && /usr/bin/cmake -E create_symlink clang-23 /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/./bin/clang++ && cd /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/tools/clang/tools/driver && /usr/bin/cmake -E create_symlink clang-23 /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/./bin/clang-cl && cd /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/tools/clang/tools/driver && /usr/bin/cmake -E create_symlink clang-23 /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/./bin/clang-cpp && cd /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/tools/clang/tools/driver && /usr/bin/python3 /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/llvm-project/clang/tools/driver/../../utils/perf-training/perf-helper.py bolt-optimize --method INSTRUMENT --input /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/bin/clang-23 --instrumented-output /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/./bin/clang-bolt.inst --fdata /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/tools/clang/tools/driver/../../utils/perf-training/prof.fdata --perf-training-binary-dir /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/tools/clang/tools/driver/../../utils/perf-training --readelf /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/bin/llvm-readobj --bolt /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/bin/llvm-bolt --lit /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/./bin/llvm-lit --merge-fdata /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/bin/merge-fdata
Running: /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/bin/llvm-bolt /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/bin/clang-23 -o /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/./bin/clang-bolt.inst -instrument --instrumentation-file-append-pid --instrumentation-file=/home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/tools/clang/tools/driver/../../utils/perf-training/prof.fdata
BOLT-INFO: shared object or position-independent executable detected
BOLT-INFO: Target architecture: aarch64
BOLT-INFO: BOLT version: <unknown>
BOLT-INFO: first alloc address is 0x0
BOLT-INFO: creating new program header table at address 0x9000000, offset 0x9000000
BOLT-INFO: enabling relocation mode
BOLT-INFO: forcing -jump-tables=move for instrumentation
BOLT-WARNING: 1 collisions detected while hashing binary objects. Use -v=1 to see the list.
BOLT-INFO: PointerAuthCFIAnalyzer ran on 2 functions. Ignored 0 functions (0.00%) because of CFI inconsistencies
BOLT-INFO: number of removed linker-inserted veneers: 0
BOLT-INFO: 0 out of 161584 functions in the binary (0.0%) have non-empty execution profile
BOLT-INSTRUMENTER: Number of indirect call site descriptors: 59398
BOLT-INSTRUMENTER: Number of indirect call target descriptors: 159320
BOLT-INSTRUMENTER: Number of function descriptors: 159309
BOLT-INSTRUMENTER: Number of branch counters: 2076027
BOLT-INSTRUMENTER: Number of ST leaf node counters: 1057297
BOLT-INSTRUMENTER: Number of direct call counters: 0
BOLT-INSTRUMENTER: Total number of counters: 3133324
BOLT-INSTRUMENTER: Total size of counters: 25066592 bytes (static alloc memory)
BOLT-INSTRUMENTER: Total size of string table emitted: 16793015 bytes in file
BOLT-INSTRUMENTER: Total size of descriptors: 232318948 bytes in file
BOLT-INSTRUMENTER: Profile will be saved to file /home/buildbot/workspace/bolt-aarch64-ubuntu-clang/build/tools/clang/tools/driver/../../utils/perf-training/prof.fdata
BOLT-INFO: removed 20961 empty blocks
BOLT-INFO: merged 6 duplicate CFG edges
BOLT-INFO: Starting stub-insertion pass
BOLT-INFO: Inserted 1502 stubs in the hot area and 0 stubs in the cold area. Shared 196950 times, iterated 4 times.
BOLT-INFO: rewritten pac-ret DWARF info in 2 out of 161881 functions (0.00%).
BOLT-INFO: padding code to 0x13c00000 to accommodate hot text
BOLT-INFO: output linked against instrumentation runtime library, lib entry point is 0x169b8960
BOLT-INFO: clear procedure is 0x169b7580
BOLT-INFO: patched build-id (flipped last bit)
BOLT-INFO: setting __bolt_runtime_start to 0x169b8960
BOLT-INFO: setting __bolt_runtime_fini to 0x169b8a00
BOLT-INFO: setting __hot_start to 0x9200000
BOLT-INFO: setting __hot_end to 0x13a6edc4
BOLT-INFO: runtime library finalization was hooked via DT_FINI, set to 0x169b8a00

```

</details>

https://github.com/llvm/llvm-project/pull/195119