[libcxx-commits] [PATCH] D142864: [libc++] `<algorithm>`: `ranges::minmax` should dereference iterators only once

[Igor Zhukov via Phabricator via libcxx-commits]

fsb4000 marked an inline comment as done.
fsb4000 added inline comments.


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Comment at: libcxx/include/__algorithm/ranges_minmax.h:140
+      // This initialization is correct, similar to the N4928 [dcl.init.aggr]/6 example
+      minmax_result<_ValueT> __result = {static_cast<_ValueT>(*__found_min), __result.min};
+      return __result;
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philnik wrote:
> What are these `static_cast`s for?
MS STL uses the `static_cast`s. I used for consistency with MS STL. I asked them why the static_cast are needed and I added more `static_cast`s here. After their answer and if the `static_cast`s are optionally needed I could remove them.


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Comment at: libcxx/include/__algorithm/ranges_minmax.h:149
+
+    while (++__first != __last) { // process one or two elements
+      _It __prev = __first;
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philnik wrote:
> Why are you effectively re-implementing `minmax_element` here?
To implement `special-case the one element case` without adding an addional if.

Ok, I try another approach.


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  https://reviews.llvm.org/D142864/new/

https://reviews.llvm.org/D142864