[llvm] [LV][NFC] Use APFloat class when printing out costs per lane (PR #201824)

[David Sherwood via llvm-commits]

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@@ -47,6 +47,14 @@ using VectorParts = SmallVector<Value *, 2>;
 #define LV_NAME "loop-vectorize"
 #define DEBUG_TYPE LV_NAME
 
+#if !defined(NDEBUG)
+// It is sometimes necessary to disable printing of metadata in tests in order
+// to avoid non-deterministic behaviour.
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david-arm wrote:

OK, but I'm not clear what you want me to do here. Are you asking to add some comments above the option to explain more precisely why this flag is useful? Or do you want me to change the behaviour of the flag by only preventing printing of metadata created by vplan?

https://github.com/llvm/llvm-project/pull/201824