[clang] [llvm] [mlir] IR: Promote "denormal-fp-math" to a first class attribute (PR #174293)

[Mikael Holmen via cfe-commits]

mikaelholmen wrote:

Hi @arsenm 

With
```
clang -cc1 -S -fmath-errno -fdenormal-fp-math-f32=preserve-sign,preserve-sign -O1 -o bbi-114859.s bbi-114859.c
```
I get
```
denormal_fpenv attribute may not apply to call sites
  %sqrtf = tail call float @sqrtf(float noundef -1.000000e+00) #1
in function foo
fatal error: error in backend: Broken function found, compilation aborted!
```
with this patch.

[bbi-114859.c.gz](https://github.com/user-attachments/files/25124147/bbi-114859.c.gz)

https://github.com/llvm/llvm-project/pull/174293