[PATCH] D83192: Fix off by one error in Bitfields

[Guillaume Chatelet via Phabricator via llvm-commits]

gchatelet created this revision.
gchatelet added a reviewer: courbet.
Herald added subscribers: llvm-commits, dexonsmith.
Herald added a project: LLVM.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D83192

Files:
  llvm/include/llvm/ADT/Bitfields.h


Index: llvm/include/llvm/ADT/Bitfields.h
===================================================================
--- llvm/include/llvm/ADT/Bitfields.h
+++ llvm/include/llvm/ADT/Bitfields.h
@@ -227,7 +227,7 @@
     static constexpr unsigned Shift = Offset;
     static constexpr unsigned Bits = Size;
     static constexpr unsigned FirstBit = Offset;
-    static constexpr unsigned LastBit = Shift + Bits;
+    static constexpr unsigned LastBit = Shift + Bits - 1;
 
   private:
     template <typename, typename> friend struct bitfields_details::Impl;
@@ -273,7 +273,7 @@
 
   /// Returns whether the two bitfields share common bits.
   template <typename A, typename B> static constexpr bool isOverlapping() {
-    return A::LastBit > B::FirstBit && B::LastBit > A::FirstBit;
+    return A::LastBit >= B::FirstBit && B::LastBit >= A::FirstBit;
   }
 };
 


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