[clang] [llvm] [FMV][AArch64] Allow user to override version priority. (PR #150267)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-armv8-quick` running on `linaro-clang-armv8-quick` while building `clang,llvm` at step 5 "ninja check 1".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/154/builds/25017

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

```
Step 5 (ninja check 1) failure: stage 1 checked (failure)
******************** TEST 'Clang :: CodeGen/AArch64/fmv-explicit-priority.c' FAILED ********************
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 2
/home/tcwg-buildbot/worker/clang-armv8-quick/stage1/bin/clang -cc1 -internal-isystem /home/tcwg-buildbot/worker/clang-armv8-quick/stage1/lib/clang/22/include -nostdsysteminc -triple aarch64-none-linux-gnu -O3 -fno-inline -emit-llvm -o - /home/tcwg-buildbot/worker/clang-armv8-quick/llvm/clang/test/CodeGen/AArch64/fmv-explicit-priority.c | /home/tcwg-buildbot/worker/clang-armv8-quick/stage1/bin/FileCheck /home/tcwg-buildbot/worker/clang-armv8-quick/llvm/clang/test/CodeGen/AArch64/fmv-explicit-priority.c
# executed command: /home/tcwg-buildbot/worker/clang-armv8-quick/stage1/bin/clang -cc1 -internal-isystem /home/tcwg-buildbot/worker/clang-armv8-quick/stage1/lib/clang/22/include -nostdsysteminc -triple aarch64-none-linux-gnu -O3 -fno-inline -emit-llvm -o - /home/tcwg-buildbot/worker/clang-armv8-quick/llvm/clang/test/CodeGen/AArch64/fmv-explicit-priority.c
# executed command: /home/tcwg-buildbot/worker/clang-armv8-quick/stage1/bin/FileCheck /home/tcwg-buildbot/worker/clang-armv8-quick/llvm/clang/test/CodeGen/AArch64/fmv-explicit-priority.c
# .---command stderr------------
# | /home/tcwg-buildbot/worker/clang-armv8-quick/llvm/clang/test/CodeGen/AArch64/fmv-explicit-priority.c:53:11: error: CHECK: expected string not found in input
# | // CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) vscale_range(1,16)
# |           ^
# | <stdin>:39:11: note: scanning from here
# |  ret i32 0
# |           ^
# | /home/tcwg-buildbot/worker/clang-armv8-quick/llvm/clang/test/CodeGen/AArch64/fmv-explicit-priority.c:57:16: error: CHECK-NEXT: expected string not found in input
# | // CHECK-NEXT: [[CALL:%.*]] = tail call i32 @foo._Mlse()
# |                ^
# | <stdin>:44:7: note: scanning from here
# | entry:
# |       ^
# | <stdin>:45:2: note: possible intended match here
# |  %call = tail call i32 @foo() #13
# |  ^
# | /home/tcwg-buildbot/worker/clang-armv8-quick/llvm/clang/test/CodeGen/AArch64/fmv-explicit-priority.c:65:16: error: CHECK-NEXT: expected string not found in input
# | // CHECK-NEXT: [[CALL:%.*]] = tail call i32 @foo._Mlse()
# |                ^
# | <stdin>:51:7: note: scanning from here
# | entry:
# |       ^
# | <stdin>:52:2: note: possible intended match here
# |  %call = tail call i32 @foo() #13
# |  ^
# | /home/tcwg-buildbot/worker/clang-armv8-quick/llvm/clang/test/CodeGen/AArch64/fmv-explicit-priority.c:77:11: error: CHECK: expected string not found in input
# | // CHECK: Function Attrs: mustprogress nofree noinline norecurse nosync nounwind willreturn memory(none) vscale_range(1,16)
# |           ^
# | <stdin>:60:15: note: scanning from here
# |  ret i32 %call
# |               ^
# | /home/tcwg-buildbot/worker/clang-armv8-quick/llvm/clang/test/CodeGen/AArch64/fmv-explicit-priority.c:81:16: error: CHECK-NEXT: expected string not found in input
# | // CHECK-NEXT: [[CALL:%.*]] = tail call i32 @foo.default()
# |                ^
# | <stdin>:65:7: note: scanning from here
# | entry:
# |       ^
# | <stdin>:66:2: note: possible intended match here
# |  %call = tail call i32 @foo() #13
# |  ^
# | /home/tcwg-buildbot/worker/clang-armv8-quick/llvm/clang/test/CodeGen/AArch64/fmv-explicit-priority.c:114:11: error: CHECK: expected string not found in input
...

```

</details>

https://github.com/llvm/llvm-project/pull/150267