[clang] [llvm] [clang] Reland Add tanf16 builtin and support for tan constrained intrinsic (PR #94559)

[Arthur Eubanks via cfe-commits]

aeubanks wrote:

I believe this has exposed a preexisting issue in isel with tan:

```
$ cat /tmp/b.ll
target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"
target triple = "thumbv7-unknown-linux-android26"

define <2 x float> @g() {
entry:
  %0 = call <2 x float> @llvm.tan.v2f32(<2 x float> zeroinitializer)
  ret <2 x float> %0
}
$ llc /tmp/b.ll -o /dev/null
LLVM ERROR: Cannot select: t3: v2f32 = ftan t15                                                                                                                                                                                                                                                                    
  t15: v2f32 = bitcast t14                                                                                                                                                                                                                                                                                         
    t14: v2i32 = ARMISD::VMOVIMM TargetConstant:i32<0>                                                                                                   
      t13: i32 = TargetConstant<0>                                                                                                                                                                                                                                                                                 
```

https://github.com/llvm/llvm-project/pull/94559