[llvm] [AMDGPU][MIR] Serialize NumPhysicalVGPRSpillLanes (PR #115291)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-gcc-ubuntu` running on `sie-linux-worker3` while building `llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/174/builds/8049

<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 :: tools/llvm-reduce/mir/preserve-machine-function-info-amdgpu.mir' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 2: llvm-reduce -abort-on-invalid-reduction -simplify-mir -mtriple=amdgcn-amd-amdhsa -mcpu=gfx908 --test /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/FileCheck --test-arg --check-prefix=CHECK-INTERESTINGNESS --test-arg /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/test/tools/llvm-reduce/mir/preserve-machine-function-info-amdgpu.mir --test-arg --input-file /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/test/tools/llvm-reduce/mir/preserve-machine-function-info-amdgpu.mir -o /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/test/tools/llvm-reduce/mir/Output/preserve-machine-function-info-amdgpu.mir.tmp 2> /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/test/tools/llvm-reduce/mir/Output/preserve-machine-function-info-amdgpu.mir.tmp.log
+ llvm-reduce -abort-on-invalid-reduction -simplify-mir -mtriple=amdgcn-amd-amdhsa -mcpu=gfx908 --test /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/FileCheck --test-arg --check-prefix=CHECK-INTERESTINGNESS --test-arg /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/test/tools/llvm-reduce/mir/preserve-machine-function-info-amdgpu.mir --test-arg --input-file /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/test/tools/llvm-reduce/mir/preserve-machine-function-info-amdgpu.mir -o /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/test/tools/llvm-reduce/mir/Output/preserve-machine-function-info-amdgpu.mir.tmp
RUN: at line 3: /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/FileCheck --check-prefix=RESULT /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/test/tools/llvm-reduce/mir/preserve-machine-function-info-amdgpu.mir < /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/test/tools/llvm-reduce/mir/Output/preserve-machine-function-info-amdgpu.mir.tmp
+ /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/build/bin/FileCheck --check-prefix=RESULT /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/test/tools/llvm-reduce/mir/preserve-machine-function-info-amdgpu.mir
/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/test/tools/llvm-reduce/mir/preserve-machine-function-info-amdgpu.mir:55:16: error: RESULT-NEXT: is not on the line after the previous match
# RESULT-NEXT: wwmReservedRegs:
               ^
<stdin>:64:2: note: 'next' match was here
 wwmReservedRegs:
 ^
<stdin>:62:14: note: previous match ended here
 occupancy: 8
             ^
<stdin>:63:1: note: non-matching line after previous match is here
 numPhysicalVGPRSpillLanes: 0
^

Input file: <stdin>
Check file: /home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/test/tools/llvm-reduce/mir/preserve-machine-function-info-amdgpu.mir

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

Input was:
<<<<<<
          1: --- | 
          2:  ; ModuleID = '/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/test/tools/llvm-reduce/mir/preserve-machine-function-info-amdgpu.mir' 
          3:  source_filename = "/home/buildbot/buildbot-root/llvm-clang-x86_64-gcc-ubuntu/llvm-project/llvm/test/tools/llvm-reduce/mir/preserve-machine-function-info-amdgpu.mir" 
          4:  target datalayout = "e-p:64:64-p1:64:64-p2:32:32-p3:32:32-p4:64:64-p5:32:32-p6:32:32-p7:160:256:256:32-p8:128:128-p9:192:256:256:32-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64-S32-A5-G1-ni:7:8:9" 
          5:   
          6:  define void @func() { 
          7:  ret void 
          8:  } 
          9:  
         10: ... 
         11: --- 
         12: name: func 
check:7      ^~~~~~~~~~
         13: alignment: 1 
         14: tracksRegLiveness: true 
         15: noPhis: true 
         16: isSSA: true 
         17: noVRegs: false 
         18: hasFakeUses: false 
         19: registers: 
         20:  - { id: 0, class: vgpr_32 } 
...

```

</details>

https://github.com/llvm/llvm-project/pull/115291