[clang] [llvm] [ConstantRange] Estimate tighter lower (upper) bounds for masked binary and (or) (PR #120352)

[Stephen Senran Zhang via llvm-commits]

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@@ -1538,10 +1625,17 @@ ConstantRange ConstantRange::binaryOr(const ConstantRange &Other) const {
 
   ConstantRange KnownBitsRange =
       fromKnownBits(toKnownBits() | Other.toKnownBits(), false);
+
+  //      ~a & ~b    >= x
+  // <=>  ~(~a & ~b) <= ~x
+  // <=>  a | b      <= ~x
+  // <=>  a | b      <  ~x + 1
+  // thus, UpperBound(a | b) == ~LowerBound(~a & ~b) + 1
+  auto UpperBound =
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zsrkmyn wrote:

Fixed! Thx!

https://github.com/llvm/llvm-project/pull/120352