[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 `openmp-offload-sles-build-only` running on `rocm-worker-hw-04-sles` while building `llvm` at step 8 "Add check check-llvm".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/140/builds/15934

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

```
Step 8 (Add check check-llvm) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 2: /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 < /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll | /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/FileCheck -check-prefixes=GFX9,GFX900 /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll
+ /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/FileCheck -check-prefixes=GFX9,GFX900 /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll
+ /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900
RUN: at line 3: /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx90a < /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll | /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/FileCheck -check-prefixes=GFX9,GFX90APLUS,GFX90A /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll
+ /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx90a
+ /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.build/bin/FileCheck -check-prefixes=GFX9,GFX90APLUS,GFX90A /home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll
/home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll:3616:16: error: GFX90A-NEXT: is not on the line after the previous match
; GFX90A-NEXT: s_mov_b32 s10, s9
               ^
<stdin>:2963:2: note: 'next' match was here
 s_mov_b32 s10, s9
 ^
<stdin>:2961:11: note: previous match ended here
 ;;#ASMEND
          ^
<stdin>:2962:1: note: non-matching line after previous match is here
 s_mov_b32 s8, s9
^
/home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll:3690:20: error: GFX90APLUS-NEXT: expected string not found in input
; GFX90APLUS-NEXT: ; def s[8:9]
                   ^
<stdin>:3037:13: note: scanning from here
 ;;#ASMSTART
            ^
<stdin>:3038:2: note: possible intended match here
 ; def s[4:5]
 ^
/home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll:4141:16: error: GFX90A-NEXT: is not on the line after the previous match
; GFX90A-NEXT: s_mov_b32 s10, s5
               ^
<stdin>:3516:2: note: 'next' match was here
 s_mov_b32 s10, s5
 ^
<stdin>:3514:11: note: previous match ended here
 ;;#ASMEND
          ^
<stdin>:3515:1: note: non-matching line after previous match is here
 s_mov_b32 s8, s9
^
/home/botworker/bbot/builds/openmp-offload-sles-build/llvm.src/llvm/test/CodeGen/AMDGPU/shufflevector.v4p3.v2p3.ll:5044:16: error: GFX90A-NEXT: expected string not found in input
; GFX90A-NEXT: ; def s[8:9]
               ^
<stdin>:4470:13: note: scanning from here
 ;;#ASMSTART
            ^
...

```

</details>

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