[llvm] AArch64: Fix undefined behavior in sme calling convention test (PR #165183)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-aarch64-sve2-vla` running on `linaro-g4-02` while building `llvm` at step 7 "ninja check 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/198/builds/9138

<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 'SanitizerCommon-asan-aarch64-Linux :: compress_stack_depot.cpp' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/stage1/./bin/clang  --driver-mode=g++ -gline-tables-only -fsanitize=address   -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta  -funwind-tables  -I/home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test -ldl /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test/sanitizer_common/TestCases/compress_stack_depot.cpp -fsanitize-memory-track-origins=1 -o /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-aarch64-Linux/Output/compress_stack_depot.cpp.tmp # RUN: at line 1
+ /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/stage1/./bin/clang --driver-mode=g++ -gline-tables-only -fsanitize=address -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta -funwind-tables -I/home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test -ldl /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test/sanitizer_common/TestCases/compress_stack_depot.cpp -fsanitize-memory-track-origins=1 -o /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-aarch64-Linux/Output/compress_stack_depot.cpp.tmp
clang: warning: argument unused during compilation: '-fsanitize-memory-track-origins=1' [-Wunused-command-line-argument]
env ASAN_OPTIONS="compress_stack_depot=0:malloc_context_size=128:verbosity=1"  /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-aarch64-Linux/Output/compress_stack_depot.cpp.tmp 2>&1 | FileCheck /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test/sanitizer_common/TestCases/compress_stack_depot.cpp --implicit-check-not="StackDepot released" # RUN: at line 2
+ env ASAN_OPTIONS=compress_stack_depot=0:malloc_context_size=128:verbosity=1 /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-aarch64-Linux/Output/compress_stack_depot.cpp.tmp
+ FileCheck /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test/sanitizer_common/TestCases/compress_stack_depot.cpp '--implicit-check-not=StackDepot released'
env ASAN_OPTIONS="compress_stack_depot=-1:malloc_context_size=128:verbosity=1"  /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-aarch64-Linux/Output/compress_stack_depot.cpp.tmp 2>&1 | FileCheck /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test/sanitizer_common/TestCases/compress_stack_depot.cpp --check-prefixes=COMPRESS # RUN: at line 3
+ env ASAN_OPTIONS=compress_stack_depot=-1:malloc_context_size=128:verbosity=1 /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-aarch64-Linux/Output/compress_stack_depot.cpp.tmp
+ FileCheck /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test/sanitizer_common/TestCases/compress_stack_depot.cpp --check-prefixes=COMPRESS
env ASAN_OPTIONS="compress_stack_depot=-2:malloc_context_size=128:verbosity=1"  /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-aarch64-Linux/Output/compress_stack_depot.cpp.tmp 2>&1 | FileCheck /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test/sanitizer_common/TestCases/compress_stack_depot.cpp --check-prefixes=COMPRESS # RUN: at line 4
+ env ASAN_OPTIONS=compress_stack_depot=-2:malloc_context_size=128:verbosity=1 /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-aarch64-Linux/Output/compress_stack_depot.cpp.tmp
+ FileCheck /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test/sanitizer_common/TestCases/compress_stack_depot.cpp --check-prefixes=COMPRESS
env ASAN_OPTIONS="compress_stack_depot=1:malloc_context_size=128:verbosity=1"  /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-aarch64-Linux/Output/compress_stack_depot.cpp.tmp 2>&1 | FileCheck /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test/sanitizer_common/TestCases/compress_stack_depot.cpp --check-prefixes=COMPRESS,THREAD # RUN: at line 5
+ env ASAN_OPTIONS=compress_stack_depot=1:malloc_context_size=128:verbosity=1 /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/stage1/runtimes/runtimes-bins/compiler-rt/test/sanitizer_common/asan-aarch64-Linux/Output/compress_stack_depot.cpp.tmp
+ FileCheck /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test/sanitizer_common/TestCases/compress_stack_depot.cpp --check-prefixes=COMPRESS,THREAD
/home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test/sanitizer_common/TestCases/compress_stack_depot.cpp:53:14: error: COMPRESS: expected string not found in input
// COMPRESS: StackDepot released {{[0-9]+}}
             ^
<stdin>:142:56: note: scanning from here
AddressSanitizer: StackDepot compression thread started
                                                       ^
<stdin>:143:19: note: possible intended match here
AddressSanitizer: StackDepot compression thread stopped
                  ^

Input file: <stdin>
Check file: /home/tcwg-buildbot/worker/clang-aarch64-sve2-vla/llvm/compiler-rt/test/sanitizer_common/TestCases/compress_stack_depot.cpp

-dump-input=help explains the following input dump.

Input was:
<<<<<<
            .
            .
            .
          137: ==192810==Installed the sigaction for signal 7 
          138: ==192810==Installed the sigaction for signal 8 
          139: ==192810==T0: FakeStack created: 0xddd4fb0e7000 -- 0xddd4fbbf0000 stack_size_log: 20; mmapped 11300K, noreserve=0, true_start: 0xddd4fb0e7000, start of first frame: 0xddd4fb0f0000 
          140: ==192810==T0: stack [0xffffe0eac000,0xffffe16ac000) size 0x800000; local=0xffffe16aa908 
          141: ==192810==AddressSanitizer Init done 
          142: AddressSanitizer: StackDepot compression thread started 
check:53'0                                                            X error: no match found
          143: AddressSanitizer: StackDepot compression thread stopped 
check:53'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
check:53'1                       ?                                      possible intended match
...

```

</details>

https://github.com/llvm/llvm-project/pull/165183