[clang] [llvm] [RegAlloc] [X86] Enable callee saved register optimization for x86 (PR #220090)

[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-b2` while building `clang,llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/137/builds/47170

<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):
--
# 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    < /b/ml-opt-dev-x86-64-b1/llvm-project/llvm/test/CodeGen/MLRegAlloc/Inputs/input.ll
# executed command: /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
# 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/test/CodeGen/MLRegAlloc/Output/dev-mode-prio-logging.ll.tmp1.readable
# executed command: /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
# 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
# executed command: /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 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
# executed command: 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
# .---command stdout------------
# | *** /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
# | ***************
# | *** 237,399 ****
# |   li_size: 0
# |   stage: 0
# |   weight: 0.0
# | ! priority: 2684354816.0
# |   reward: 0.0
# |   observation: 40
# |   li_size: 0
# |   stage: 0
# |   weight: 0.0
# | ! priority: 2684354560.0
# |   reward: 0.0
# |   observation: 41
# |   li_size: 0
# |   stage: 0
# |   weight: 0.0
# |   priority: 2684357888.0
# |   reward: 0.0
# | - observation: 42
# | - li_size: 0
# | - stage: 0
# | - weight: 0.0
# | - priority: 2684354816.0
# | - reward: 0.0
# | - observation: 43
# | - li_size: 0
# | - stage: 0
# | - weight: 0.0
# | - priority: 2684358144.0
...

```

</details>

https://github.com/llvm/llvm-project/pull/220090