[llvm] [InstCombine] Add missing constant check (PR #170068)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-aarch64-sve-vla-2stage` running on `linaro-g3-01` while building `llvm` at step 12 "ninja check 2".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/41/builds/10616

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

```
Step 12 (ninja check 2) failure: stage 2 checked (failure)
******************** TEST 'MemorySanitizer-AARCH64 :: release_origin.c' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/./bin/clang  -fsanitize=memory -mno-omit-leaf-frame-pointer -fno-omit-frame-pointer -fno-optimize-sibling-calls   -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta   -gline-tables-only -fsanitize-memory-track-origins=0 -O0 /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/compiler-rt/test/msan/release_origin.c -o /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/runtimes/runtimes-bins/compiler-rt/test/msan/AARCH64/Output/release_origin.c.tmp && env MSAN_OPTIONS=soft_rss_limit_mb=18:verbosity=1:allocator_may_return_null=1  /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/runtimes/runtimes-bins/compiler-rt/test/msan/AARCH64/Output/release_origin.c.tmp 2>&1 | FileCheck /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/compiler-rt/test/msan/release_origin.c -implicit-check-not="soft rss limit" -check-prefixes=CHECK,NOORIG # RUN: at line 1
+ /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/./bin/clang -fsanitize=memory -mno-omit-leaf-frame-pointer -fno-omit-frame-pointer -fno-optimize-sibling-calls -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta -gline-tables-only -fsanitize-memory-track-origins=0 -O0 /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/compiler-rt/test/msan/release_origin.c -o /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/runtimes/runtimes-bins/compiler-rt/test/msan/AARCH64/Output/release_origin.c.tmp
+ FileCheck /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/compiler-rt/test/msan/release_origin.c '-implicit-check-not=soft rss limit' -check-prefixes=CHECK,NOORIG
+ env MSAN_OPTIONS=soft_rss_limit_mb=18:verbosity=1:allocator_may_return_null=1 /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/runtimes/runtimes-bins/compiler-rt/test/msan/AARCH64/Output/release_origin.c.tmp
/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/./bin/clang  -fsanitize=memory -mno-omit-leaf-frame-pointer -fno-omit-frame-pointer -fno-optimize-sibling-calls   -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta   -gline-tables-only -fsanitize-memory-track-origins=2 -O0 /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/compiler-rt/test/msan/release_origin.c -o /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/runtimes/runtimes-bins/compiler-rt/test/msan/AARCH64/Output/release_origin.c.tmp && env MSAN_OPTIONS=soft_rss_limit_mb=36:verbosity=1:allocator_may_return_null=1  /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/runtimes/runtimes-bins/compiler-rt/test/msan/AARCH64/Output/release_origin.c.tmp 2>&1 | FileCheck /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/compiler-rt/test/msan/release_origin.c -implicit-check-not="soft rss limit" -check-prefixes=CHECK,ORIGIN # RUN: at line 2
+ /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/./bin/clang -fsanitize=memory -mno-omit-leaf-frame-pointer -fno-omit-frame-pointer -fno-optimize-sibling-calls -Wthread-safety -Wthread-safety-reference -Wthread-safety-beta -gline-tables-only -fsanitize-memory-track-origins=2 -O0 /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/compiler-rt/test/msan/release_origin.c -o /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/runtimes/runtimes-bins/compiler-rt/test/msan/AARCH64/Output/release_origin.c.tmp
+ FileCheck /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/compiler-rt/test/msan/release_origin.c '-implicit-check-not=soft rss limit' -check-prefixes=CHECK,ORIGIN
+ env MSAN_OPTIONS=soft_rss_limit_mb=36:verbosity=1:allocator_may_return_null=1 /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/stage2/runtimes/runtimes-bins/compiler-rt/test/msan/AARCH64/Output/release_origin.c.tmp
/home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/compiler-rt/test/msan/release_origin.c:37:12: error: ORIGIN: expected string not found in input
// ORIGIN: soft rss limit unexhausted
           ^
<stdin>:94:7: note: scanning from here
memset
      ^
<stdin>:95:1: note: possible intended match here
free
^
command line:1:22: error: IMPLICIT-CHECK-NOT: excluded string found in input
-implicit-check-not='soft rss limit'
                     ^
<stdin>:96:29: note: found here
==2381879==MemorySanitizer: soft rss limit unexhausted (36Mb vs 3Mb)
                            ^~~~~~~~~~~~~~

Input file: <stdin>
Check file: /home/tcwg-buildbot/worker/clang-aarch64-sve-vla-2stage/llvm/compiler-rt/test/msan/release_origin.c

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

Input was:
<<<<<<
            .
            .
            .
           89: MemorySanitizer: Started BackgroundThread 
           90: malloc 
           91: MemorySanitizer: RSS: 43Mb 
           92: MemorySanitizer: StackDepot: 3 ids; 9M allocated 
           93: ==2381879==MemorySanitizer: soft rss limit exhausted (36Mb vs 43Mb) 
           94: memset 
check:37'0           X error: no match found
           95: free 
check:37'0     ~~~~
check:37'1     ?     possible intended match
           96: ==2381879==MemorySanitizer: soft rss limit unexhausted (36Mb vs 3Mb) 
...

```

</details>

https://github.com/llvm/llvm-project/pull/170068