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

[Eli Friedman via llvm-commits]

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@@ -47,6 +46,9 @@
 ; RUN: %if xcore-registered-target       %{ llc %s -o - -mtriple=xcore-unknown-unknown           | FileCheck %s --check-prefixes=ALL,CHECK %}
 ; RUN: %if xtensa-registered-target      %{ llc %s -o - -mtriple=xtensa-none-elf                 | FileCheck %s --check-prefixes=ALL,CHECK %}
 
+; Note that arm64ec labels don't have a `:` so use `EC`, other tests do need the
+; `:` so directives with the function names don't get treated as labels.
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efriedma-quic wrote:

The labels do have a colon, it's just obscured by the quotes around the symbol name.

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