[llvm] [Arm64EC] Add support for `half` (PR #152843)

[Trevor Gross via llvm-commits]

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@@ -316,6 +316,11 @@ ThunkArgInfo AArch64Arm64ECCallLowering::canonicalizeThunkType(
                         ThunkArgTranslation::PointerIndirection};
   };
 
+  if (T->isHalfTy()) {
+    Out << "h";
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tgross35 wrote:

`h` makes sense considering the others are `f` and `d`. However, I don't know what the namespace is here, so please double check that this isn't problematic.

https://github.com/llvm/llvm-project/pull/152843