[clang] [llvm] [Clang][LoongArch] Support target attribute for function (PR #140700)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-gcc-ubuntu-no-asserts` running on `doug-worker-6` while building `clang,llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/202/builds/1531

<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 :: CodeGen/LoongArch/targetattr.c' FAILED ********************
Exit Code: 1

Command Output (stderr):
--
/home/buildbot/buildbot-root/gcc-no-asserts/build/bin/clang --target=loongarch64-linux-gnu /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/clang/test/CodeGen/LoongArch/targetattr.c -S -emit-llvm -o -    | /home/buildbot/buildbot-root/gcc-no-asserts/build/bin/FileCheck /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/clang/test/CodeGen/LoongArch/targetattr.c # RUN: at line 2
+ /home/buildbot/buildbot-root/gcc-no-asserts/build/bin/clang --target=loongarch64-linux-gnu /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/clang/test/CodeGen/LoongArch/targetattr.c -S -emit-llvm -o -
+ /home/buildbot/buildbot-root/gcc-no-asserts/build/bin/FileCheck /home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/clang/test/CodeGen/LoongArch/targetattr.c
/home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/clang/test/CodeGen/LoongArch/targetattr.c:8:16: error: CHECK-NEXT: is not on the line after the previous match
// CHECK-NEXT: [[ENTRY:.*:]]
               ^
<stdin>:11:1: note: 'next' match was here
; Function Attrs: noinline nounwind optnone
^
<stdin>:7:40: note: previous match ended here
define dso_local void @testdiv32() #0 {
                                       ^
<stdin>:8:1: note: non-matching line after previous match is here
 ret void
^
/home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/clang/test/CodeGen/LoongArch/targetattr.c:16:16: error: CHECK-NEXT: is not on the line after the previous match
// CHECK-NEXT: [[ENTRY:.*:]]
               ^
<stdin>:16:1: note: 'next' match was here
; Function Attrs: noinline nounwind optnone
^
<stdin>:12:46: note: previous match ended here
define dso_local void @testLoongarch64() #1 {
                                             ^
<stdin>:13:1: note: non-matching line after previous match is here
 ret void
^
/home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/clang/test/CodeGen/LoongArch/targetattr.c:24:16: error: CHECK-NEXT: is not on the line after the previous match
// CHECK-NEXT: [[ENTRY:.*:]]
               ^
<stdin>:21:1: note: 'next' match was here
; Function Attrs: noinline nounwind optnone
^
<stdin>:17:42: note: previous match ended here
define dso_local void @testLa64v10() #1 {
                                         ^
<stdin>:18:1: note: non-matching line after previous match is here
 ret void
^
/home/buildbot/buildbot-root/gcc-no-asserts/llvm-project/clang/test/CodeGen/LoongArch/targetattr.c:32:16: error: CHECK-NEXT: is not on the line after the previous match
// CHECK-NEXT: [[ENTRY:.*:]]
               ^
<stdin>:26:1: note: 'next' match was here
; Function Attrs: noinline nounwind optnone
^
...

```

</details>

https://github.com/llvm/llvm-project/pull/140700