[llvm] PeepholeOpt: Do not add subregister indexes to reg_sequence operands (PR #124111)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-x86_64-debian-dylib` running on `gribozavr4` while building `llvm` at step 7 "test-build-unified-tree-check-llvm".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/60/builds/18400

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

```
Step 7 (test-build-unified-tree-check-llvm) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 2: /b/1/llvm-x86_64-debian-dylib/build/bin/llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 < /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll | /b/1/llvm-x86_64-debian-dylib/build/bin/FileCheck -check-prefixes=GFX9,GFX900 /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll
+ /b/1/llvm-x86_64-debian-dylib/build/bin/FileCheck -check-prefixes=GFX9,GFX900 /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll
+ /b/1/llvm-x86_64-debian-dylib/build/bin/llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900
RUN: at line 3: /b/1/llvm-x86_64-debian-dylib/build/bin/llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx90a < /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll | /b/1/llvm-x86_64-debian-dylib/build/bin/FileCheck -check-prefixes=GFX9,GFX90APLUS,GFX90A /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll
+ /b/1/llvm-x86_64-debian-dylib/build/bin/FileCheck -check-prefixes=GFX9,GFX90APLUS,GFX90A /b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll
+ /b/1/llvm-x86_64-debian-dylib/build/bin/llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx90a
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll:3610:16: error: GFX90A-NEXT: is not on the line after the previous match
; GFX90A-NEXT: s_mov_b32 s10, s9
               ^
<stdin>:2961:2: note: 'next' match was here
 s_mov_b32 s10, s9
 ^
<stdin>:2959:11: note: previous match ended here
 ;;#ASMEND
          ^
<stdin>:2960:1: note: non-matching line after previous match is here
 s_mov_b32 s8, s9
^
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll:3684:20: error: GFX90APLUS-NEXT: expected string not found in input
; GFX90APLUS-NEXT: ; def s[8:9]
                   ^
<stdin>:3035:13: note: scanning from here
 ;;#ASMSTART
            ^
<stdin>:3036:2: note: possible intended match here
 ; def s[4:5]
 ^
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll:4133:16: error: GFX90A-NEXT: is not on the line after the previous match
; GFX90A-NEXT: s_mov_b32 s10, s5
               ^
<stdin>:3512:2: note: 'next' match was here
 s_mov_b32 s10, s5
 ^
<stdin>:3510:11: note: previous match ended here
 ;;#ASMEND
          ^
<stdin>:3511:1: note: non-matching line after previous match is here
 s_mov_b32 s8, s9
^
/b/1/llvm-x86_64-debian-dylib/llvm-project/llvm/test/CodeGen/AMDGPU/shufflevector.v4f32.v2f32.ll:5036:16: error: GFX90A-NEXT: expected string not found in input
; GFX90A-NEXT: ; def s[8:9]
               ^
<stdin>:4466:13: note: scanning from here
 ;;#ASMSTART
            ^
...

```

</details>

https://github.com/llvm/llvm-project/pull/124111