[llvm] [PHIElimination] Reuse existing COPY in predecessor basic block (PR #131837)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `ml-opt-dev-x86-64` running on `ml-opt-dev-x86-64-b1` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/137/builds/21303

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/MLRegAlloc/dev-mode-prio-logging.ll' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
210c210
< priority: 2684357632.0
---
> priority: 2684357888.0
240c240
< priority: 3518.0
---
> priority: 3534.0
252c252
< priority: 3502.0
---
> priority: 3518.0
258c258
< priority: 3006.0
---
> priority: 3022.0
264c264
< priority: 2990.0
---
> priority: 3006.0
276c276
< priority: 4030.0
---
> priority: 4046.0
282c282
< priority: 3758099456.0
---
> priority: 3758099712.0
294c294
< priority: 4288.0
---
> priority: 4304.0

--
Command Output (stderr):
--
/b/ml-opt-dev-x86-64-b1/build/bin/llc -o /dev/null -mtriple=x86_64-linux-unknown -regalloc=greedy    -regalloc-enable-priority-advisor=development    -regalloc-priority-training-log=/b/ml-opt-dev-x86-64-b1/build/test/CodeGen/MLRegAlloc/Output/dev-mode-prio-logging.ll.tmp1    < /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/MLRegAlloc/Inputs/input.ll # RUN: at line 6
+ /b/ml-opt-dev-x86-64-b1/build/bin/llc -o /dev/null -mtriple=x86_64-linux-unknown -regalloc=greedy -regalloc-enable-priority-advisor=development -regalloc-priority-training-log=/b/ml-opt-dev-x86-64-b1/build/test/CodeGen/MLRegAlloc/Output/dev-mode-prio-logging.ll.tmp1
"/usr/bin/python3" /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/MLRegAlloc/../../../lib/Analysis/models/log_reader.py /b/ml-opt-dev-x86-64-b1/build/test/CodeGen/MLRegAlloc/Output/dev-mode-prio-logging.ll.tmp1 > /b/ml-opt-dev-x86-64-b1/build/test/CodeGen/MLRegAlloc/Output/dev-mode-prio-logging.ll.tmp1.readable # RUN: at line 10
+ /usr/bin/python3 /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/MLRegAlloc/../../../lib/Analysis/models/log_reader.py /b/ml-opt-dev-x86-64-b1/build/test/CodeGen/MLRegAlloc/Output/dev-mode-prio-logging.ll.tmp1
/b/ml-opt-dev-x86-64-b1/build/bin/FileCheck --input-file /b/ml-opt-dev-x86-64-b1/build/test/CodeGen/MLRegAlloc/Output/dev-mode-prio-logging.ll.tmp1.readable /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/MLRegAlloc/dev-mode-prio-logging.ll --check-prefixes=CHECK,NOML # RUN: at line 11
+ /b/ml-opt-dev-x86-64-b1/build/bin/FileCheck --input-file /b/ml-opt-dev-x86-64-b1/build/test/CodeGen/MLRegAlloc/Output/dev-mode-prio-logging.ll.tmp1.readable /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/MLRegAlloc/dev-mode-prio-logging.ll --check-prefixes=CHECK,NOML
diff /b/ml-opt-dev-x86-64-b1/build/test/CodeGen/MLRegAlloc/Output/dev-mode-prio-logging.ll.tmp1.readable /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/MLRegAlloc/Inputs/reference-prio-log-noml.txt # RUN: at line 12
+ diff /b/ml-opt-dev-x86-64-b1/build/test/CodeGen/MLRegAlloc/Output/dev-mode-prio-logging.ll.tmp1.readable /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/MLRegAlloc/Inputs/reference-prio-log-noml.txt

...

```

</details>

https://github.com/llvm/llvm-project/pull/131837