[clang] [llvm] [AArch64] Refactor implementation of FP8 types (NFC) (PR #118969)

[Momchil Velikov via cfe-commits]

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@@ -650,6 +655,8 @@ llvm::Type *CodeGenTypes::ConvertType(QualType T) {
     // An ext_vector_type of Bool is really a vector of bits.
     llvm::Type *IRElemTy = VT->isExtVectorBoolType()
                                ? llvm::Type::getInt1Ty(getLLVMContext())
+                           : VT->getElementType()->isMFloat8Type()
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momchil-velikov wrote:

Yeah, might be worth adding a comment, if it's not obvious.
We need to have a special case for `__mf8` mapping to `<1 x i8>` in these two places (among others), in other words, we're have to break the abstraction a bit _anyway_, thus instead of first constructing  a `<1 x i8>` and then extracting the element type, we can simply use `i8` directly.

https://github.com/llvm/llvm-project/pull/118969