[libcxx-commits] [libcxx] [libc++] Adds __cpp_lib_three_way_comparison FTM. (PR #91515)

[Mark de Wever via libcxx-commits]

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@@ -1236,7 +1236,8 @@ def add_version_header(tc):
         },
         {
             "name": "__cpp_lib_three_way_comparison",
-            "values": {"c++20": 201907},
+            "values": {"c++20": 201711},
+            # {"c++20": 201711} # P1614R2 The Mothership has Landed (see P1902R1 Missing feature-test macros 2017-2019)
             "headers": ["compare"],
             "unimplemented": True,
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mordante wrote:

Yes it should. After changing I formatted the file and  it seems the file was not formatted before so got a lot of unrelated changes. Seems I forgot to add the hunk that removed this line.

Indeed `long double` is not entirely complete; When NaNs are used the ordering is not available. (`long double` on some platforms has padding bits, which we can't handle.)

This was pointed out in the bug report and I didn't get strong objections to set the FTM. IMO `long double` is rather rare so I don't feel the omission is a huge issue. Still it would be great if we could enable this.

(As pointed out above P1614R2 did not actually bump the FTM; it was fixed later.)

https://github.com/llvm/llvm-project/pull/91515