[llvm] [WIP][X86] Always use 128-bit V_SET0/AVX512_128_SET0 patterns, along with SUBREG_TO_REG for extension to 256/512-bit vectors (PR #212950)

[via llvm-commits]

github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Linux-->
# :penguin: Linux x64 Test Results

* 179851 tests passed
* 3601 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### LLVM
<details>
<summary>LLVM.CodeGen/MIR/X86/machine-verifier-address.mir</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
not --crash /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/llc -mtriple=x86_64 -run-pass none -o /dev/null /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/CodeGen/MIR/X86/machine-verifier-address.mir 2>&1 | /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/FileCheck /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/CodeGen/MIR/X86/machine-verifier-address.mir
# executed command: not --crash /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/llc -mtriple=x86_64 -run-pass none -o /dev/null /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/CodeGen/MIR/X86/machine-verifier-address.mir
# note: command had no output on stdout or stderr
# error: command failed with exit status: 1
# executed command: /home/gha/actions-runner/_work/llvm-project/llvm-project/build/bin/FileCheck /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/CodeGen/MIR/X86/machine-verifier-address.mir
# .---command stderr------------
# | /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/CodeGen/MIR/X86/machine-verifier-address.mir:23:11: error: CHECK: expected string not found in input
# |  ; CHECK: *** Bad machine code: Scale factor in address must be 1, 2, 4 or 8 ***
# |           ^
# | <stdin>:1:1: note: scanning from here
# | error: /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/CodeGen/MIR/X86/machine-verifier-address.mir:19:16: unknown machine instruction name 'AVX_SET0'
# | ^
# | 
# | Input file: <stdin>
# | Check file: /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/CodeGen/MIR/X86/machine-verifier-address.mir
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             1: error: /home/gha/actions-runner/_work/llvm-project/llvm-project/llvm/test/CodeGen/MIR/X86/machine-verifier-address.mir:19:16: unknown machine instruction name 'AVX_SET0' 
# | check:23'0    {                                                                                                                                                                            search range start (exclusive)
# | check:23'1                                                                                                                                                                                 error: no match found in search range
# |             2:  %3:vr256 = AVX_SET0 
# |             3:  ^ 
# |             4:  
# | check:23'2      } search range end (exclusive)
# | >>>>>>
# `-----------------------------
# error: command failed with exit status: 1

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/212950