[clang] [CIR] floating-point, pointer, and function types (PR #120484)

[Erich Keane via cfe-commits]

================
@@ -18,6 +21,87 @@ mlir::MLIRContext &CIRGenTypes::getMLIRContext() const {
   return *builder.getContext();
 }
 
+/// Return true if the specified type in a function parameter or result position
+/// can be converted to a CIR type at this point. This boils down to being
+/// whether it is complete, as well as whether we've temporarily deferred
+/// expanding the type because we're in a recursive context.
+bool CIRGenTypes::isFuncParamTypeConvertible(clang::QualType type) {
+  // Some ABIs cannot have their member pointers represented in LLVM IR unless
+  // certain circumstances have been reached.
+  assert(!type->getAs<MemberPointerType>() && "NYI");
+
+  // If this isn't a tagged type, we can convert it!
----------------
erichkeane wrote:

>It is known that incomplete tag types are the only ones that are problematic in this context.

This seems inaccurate to me.  CIR doesn't seem to be able to represent(see here: https://github.com/llvm/clangir/blob/main/clang/include/clang/CIR/Dialect/IR/CIRTypes.td)  Atomic Types, BitInt types, Block types, and Matrix types upon quick look (that is perhaps an incomplete list).  

The function was written across; 
https://github.com/llvm/clangir/commit/101e732565d0e5004c5191b0053eebd8e849cade
and 
https://github.com/llvm/clangir/commit/93f55f6d43be394250009013c83d343be7c63f41

Neither of which mention those types specifically?  It seems it USED to have an assert for not-tag-type, though it isn't clear that the authors considered the above types.

Can @lanza and @bcardosolopes chime in and let me know if I'm misinterpreting the commits there?



https://github.com/llvm/llvm-project/pull/120484