[clang] Workaround for MSVC ARM64 build performance regression (PR #65215)

[Alexander Smarus via cfe-commits]

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@@ -30,6 +30,15 @@ set(LLVM_LINK_COMPONENTS
   TransformUtils
   )
 
+# Workaround for MSVC ARM64 performance regression: disable all optimizations (/Od)
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lxbndr wrote:

I was not sure if the link is acceptable to mention there. Will do, thanks!

https://github.com/llvm/llvm-project/pull/65215