[llvm] [ADT] Bitset: add shift operators, word accessors, and etc (PR #193400)

[Jiachen Yuan via llvm-commits]

================
@@ -194,6 +194,95 @@ template <unsigned NumBits> class Bitset {
     }
     return false;
   }
+
+  constexpr Bitset &operator<<=(unsigned N) {
+    if (N == 0)
+      return *this;
+    if (N >= NumBits) {
+      return *this = Bitset();
+    }
+    const unsigned WordShift = N / BitwordBits;
+    const unsigned BitShift = N % BitwordBits;
+    if (BitShift == 0) {
+      for (int I = NumWords - 1; I >= static_cast<int>(WordShift); --I)
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JiachenYuan wrote:

Thank you! I have updated to use the proposed way of writing the loops.

https://github.com/llvm/llvm-project/pull/193400