[clang] [llvm] [RISCV] Update P extension to the 018 version of the spec. (PR #170399)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

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

Full details are available at: https://lab.llvm.org/buildbot/#/builders/185/builds/30001

<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/RISCV/rvp-ext-rv32.ll' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/b/ml-opt-rel-x86-64-b1/build/bin/llc -mtriple=riscv32 -mattr=+experimental-p -enable-p-ext-codegen -verify-machineinstrs < /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/CodeGen/RISCV/rvp-ext-rv32.ll | /b/ml-opt-rel-x86-64-b1/build/bin/FileCheck --check-prefixes=CHECK,CHECK-RV32 /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/CodeGen/RISCV/rvp-ext-rv32.ll
# executed command: /b/ml-opt-rel-x86-64-b1/build/bin/llc -mtriple=riscv32 -mattr=+experimental-p -enable-p-ext-codegen -verify-machineinstrs
# executed command: /b/ml-opt-rel-x86-64-b1/build/bin/FileCheck --check-prefixes=CHECK,CHECK-RV32 /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/CodeGen/RISCV/rvp-ext-rv32.ll
# .---command stderr------------
# | /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/CodeGen/RISCV/rvp-ext-rv32.ll:719:20: error: CHECK-RV32-NEXT: expected string not found in input
# | ; CHECK-RV32-NEXT: ppack.dh a2, a4, a6
# |                    ^
# | <stdin>:629:16: note: scanning from here
# |  sll a5, a1, a2
# |                ^
# | <stdin>:630:2: note: possible intended match here
# |  ppaire.db a2, a4, a6
# |  ^
# | 
# | Input file: <stdin>
# | Check file: /b/ml-opt-rel-x86-64-b1/llvm-project/llvm/test/CodeGen/RISCV/rvp-ext-rv32.ll
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             .
# |             .
# |             .
# |           624:  sll a7, a4, a3 
# |           625:  sll a6, a6, a5 
# |           626:  sll a4, a1, a2 
# |           627:  srli a2, a2, 16 
# |           628:  srli a1, a1, 16 
# |           629:  sll a5, a1, a2 
# | next:719'0                    X error: no match found
# |           630:  ppaire.db a2, a4, a6 
# | next:719'0     ~~~~~~~~~~~~~~~~~~~~~~
# | next:719'1      ?                     possible intended match
# |           631:  pack a1, a2, a3 
# | next:719'0     ~~~~~~~~~~~~~~~~~
# |           632:  sw a1, 0(a0) 
# | next:719'0     ~~~~~~~~~~~~~~
# |           633:  ret 
# | next:719'0     ~~~~~
# |           634: .Lfunc_end42: 
# | next:719'0     ~~~~~~~~~~~~~~
# |           635:  .size test_psll_bs_vec_shamt, .Lfunc_end42-test_psll_bs_vec_shamt 
# | next:719'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...

```

</details>

https://github.com/llvm/llvm-project/pull/170399