[clang] [llvm] [HLSL] Move length support out of the DirectX Backend (PR #121611)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

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

Full details are available at: https://lab.llvm.org/buildbot/#/builders/144/builds/15275

<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 'Clang :: CodeGenHLSL/builtins/length.hlsl' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
RUN: at line 2: /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/clang -cc1 -internal-isystem /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/lib/clang/20/include -nostdsysteminc -finclude-default-header -triple  dxil-pc-shadermodel6.3-library /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGenHLSL/builtins/length.hlsl -fnative-half-type  -emit-llvm -O1 -o - | /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGenHLSL/builtins/length.hlsl
+ /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/FileCheck /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGenHLSL/builtins/length.hlsl
+ /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/bin/clang -cc1 -internal-isystem /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/build/lib/clang/20/include -nostdsysteminc -finclude-default-header -triple dxil-pc-shadermodel6.3-library /home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGenHLSL/builtins/length.hlsl -fnative-half-type -emit-llvm -O1 -o -
/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGenHLSL/builtins/length.hlsl:21:16: error: CHECK-NEXT: expected string not found in input
// CHECK-NEXT: [[VECEXT_I:%.*]] = extractelement <2 x half> [[MUL_I]], i64 0
               ^
<stdin>:16:66: note: scanning from here
 %mul.i = fmul reassoc nnan ninf nsz arcp afn <2 x half> %p0, %p0
                                                                 ^
<stdin>:16:66: note: with "MUL_I" equal to "%mul\\.i"
 %mul.i = fmul reassoc nnan ninf nsz arcp afn <2 x half> %p0, %p0
                                                                 ^
<stdin>:19:5: note: possible intended match here
 %add.i = extractelement <2 x half> %0, i64 0
    ^
/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGenHLSL/builtins/length.hlsl:36:16: error: CHECK-NEXT: expected string not found in input
// CHECK-NEXT: [[VECEXT_I:%.*]] = extractelement <3 x half> [[MUL_I]], i64 0
               ^
<stdin>:27:66: note: scanning from here
 %mul.i = fmul reassoc nnan ninf nsz arcp afn <3 x half> %p0, %p0
                                                                 ^
<stdin>:27:66: note: with "MUL_I" equal to "%mul\\.i"
 %mul.i = fmul reassoc nnan ninf nsz arcp afn <3 x half> %p0, %p0
                                                                 ^
<stdin>:32:7: note: possible intended match here
 %add.i.1 = extractelement <3 x half> %1, i64 0
      ^
/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGenHLSL/builtins/length.hlsl:53:16: error: CHECK-NEXT: expected string not found in input
// CHECK-NEXT: [[VECEXT_I:%.*]] = extractelement <4 x half> [[MUL_I]], i64 0
               ^
<stdin>:40:66: note: scanning from here
 %mul.i = fmul reassoc nnan ninf nsz arcp afn <4 x half> %p0, %p0
                                                                 ^
<stdin>:40:66: note: with "MUL_I" equal to "%mul\\.i"
 %mul.i = fmul reassoc nnan ninf nsz arcp afn <4 x half> %p0, %p0
                                                                 ^
<stdin>:47:7: note: possible intended match here
 %add.i.2 = extractelement <4 x half> %2, i64 0
      ^
/home/buildbot/buildbot-root/llvm-clang-x86_64-sie-ubuntu-fast/llvm-project/clang/test/CodeGenHLSL/builtins/length.hlsl:84:16: error: CHECK-NEXT: expected string not found in input
// CHECK-NEXT: [[VECEXT_I:%.*]] = extractelement <2 x float> [[MUL_I]], i64 0
               ^
<stdin>:62:67: note: scanning from here
 %mul.i = fmul reassoc nnan ninf nsz arcp afn <2 x float> %p0, %p0
                                                                  ^
...

```

</details>

https://github.com/llvm/llvm-project/pull/121611