Merge commit 'b09551f07408' from llvm.org/main into next

Author: git apple-llvm automerger

libcxx/include/__ranges/iota_view.h

@@ -363,15 +363,14 @@ namespace ranges {
               (integral<_Start> && integral<_BoundSentinel>) || sized_sentinel_for<_BoundSentinel, _Start>
     {
       if constexpr (__integer_like<_Start> && __integer_like<_BoundSentinel>) {
-        if (__value_ < 0) {
-          if (__bound_sentinel_ < 0) {
-            return std::__to_unsigned_like(-__value_) - std::__to_unsigned_like(-__bound_sentinel_);
-          }
-          return std::__to_unsigned_like(__bound_sentinel_) + std::__to_unsigned_like(-__value_);
-        }
-        return std::__to_unsigned_like(__bound_sentinel_) - std::__to_unsigned_like(__value_);
+        return (__value_ < 0)
+                 ? ((__bound_sentinel_ < 0)
+                        ? std::__to_unsigned_like(-__value_) - std::__to_unsigned_like(-__bound_sentinel_)
+                        : std::__to_unsigned_like(__bound_sentinel_) + std::__to_unsigned_like(-__value_))
+                 : std::__to_unsigned_like(__bound_sentinel_) - std::__to_unsigned_like(__value_);
+      } else {
+        return std::__to_unsigned_like(__bound_sentinel_ - __value_);
       }
-      return std::__to_unsigned_like(__bound_sentinel_ - __value_);
     }
   };
 

libcxx/test/std/ranges/range.factories/range.iota.view/size.pass.cpp

@@ -10,9 +10,10 @@
 
 // constexpr auto size() const requires see below;
 
-#include <ranges>
 #include <cassert>
+#include <concepts>
 #include <limits>
+#include <ranges>
 
 #include "test_macros.h"
 #include "types.h"
@@ -89,6 +90,15 @@ constexpr bool test() {
     assert(io.size() == 0);
   }
 
+  // Make sure iota_view<short, short> works properly. For details,
+  // see https://github.com/llvm/llvm-project/issues/67551.
+  {
+    static_assert(std::ranges::sized_range<std::ranges::iota_view<short, short>>);
+    std::ranges::iota_view<short, short> io(10, 20);
+    std::same_as<unsigned int> auto sz = io.size();
+    assert(sz == 10);
+  }
+
   return true;
 }