[llvm] [ADT] Refactor Bitset to Be More Constexpr-Usable and Add More Member Functions (PR #172062)

[Jiachen Yuan via llvm-commits]

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@@ -31,16 +31,24 @@ class Bitset {
   using BitWord = uintptr_t;
 
   static constexpr unsigned BitwordBits = sizeof(BitWord) * CHAR_BIT;
+  static constexpr unsigned RemainderNumBits = NumBits % BitwordBits;
+  static constexpr BitWord RemainderMask =
+      RemainderNumBits == 0 ? ~BitWord(0)
+                            : ((BitWord(1) << RemainderNumBits) - 1);
 
   static_assert(BitwordBits == 64 || BitwordBits == 32,
                 "Unsupported word size");
 
   static constexpr unsigned NumWords =
       (NumBits + BitwordBits - 1) / BitwordBits;
 
+  static constexpr unsigned getLastWordIndex() { return NumWords - 1; }
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JiachenYuan wrote:

Sure! Added.

https://github.com/llvm/llvm-project/pull/172062