[llvm] [LoongArch] Initial implementation for `enableMemCmpExpansion` hook (PR #166526)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-aarch64-sve-vla` running on `linaro-g3-04` while building `llvm` at step 7 "ninja check 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/17/builds/12521

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

```
Step 7 (ninja check 1) failure: stage 1 checked (failure)
******************** TEST 'libFuzzer-aarch64-default-Linux :: merge-sigusr.test' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
/home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/g

--
Command Output (stderr):
--
rm -rf /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp # RUN: at line 6
+ rm -rf /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp
mkdir -p /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp # RUN: at line 7
+ mkdir -p /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp
/home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/./bin/clang    -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta   --driver-mode=g++ -O2 -gline-tables-only -fsanitize=address,fuzzer -I/home/tcwg-buildbot/worker/clang-aarch64-sve-vla/llvm/compiler-rt/lib/fuzzer  -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta  /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/llvm/compiler-rt/test/fuzzer/SleepOneSecondTest.cpp -o /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/LFSIGUSR # RUN: at line 8
+ /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/./bin/clang -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta --driver-mode=g++ -O2 -gline-tables-only -fsanitize=address,fuzzer -I/home/tcwg-buildbot/worker/clang-aarch64-sve-vla/llvm/compiler-rt/lib/fuzzer -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/llvm/compiler-rt/test/fuzzer/SleepOneSecondTest.cpp -o /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/LFSIGUSR
mkdir -p /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C1 /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2 # RUN: at line 10
+ mkdir -p /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C1 /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2
echo a > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/a # RUN: at line 11
+ echo a
echo b > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/b # RUN: at line 12
+ echo b
echo c > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/c # RUN: at line 13
+ echo c
echo d > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/d # RUN: at line 14
+ echo d
echo e > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/e # RUN: at line 15
+ echo e
echo f > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/f # RUN: at line 16
+ echo f
echo g > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/g # RUN: at line 17
+ echo g
echo h > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/g # RUN: at line 18
+ echo h
echo i > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/g # RUN: at line 19
+ echo i
echo j > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/g # RUN: at line 20
+ echo j
echo k > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/g # RUN: at line 21
+ echo k
echo l > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/g # RUN: at line 22
+ echo l
echo m > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/g # RUN: at line 23
+ echo m
echo n > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/g # RUN: at line 24
+ echo n
echo o > /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2/g # RUN: at line 25
+ echo o
setsid  /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/LFSIGUSR -merge=1 -merge_control_file=/home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/MCF /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C1 /home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/C2 2>/home/tcwg-buildbot/worker/clang-aarch64-sve-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/fuzzer/AARCH64DefaultLinuxConfig/Output/merge-sigusr.test.tmp/log & export PID=$! # RUN: at line 28
+ export PID=1875274
...

```

</details>

https://github.com/llvm/llvm-project/pull/166526