[ConstantRange] Add initial support for binaryXor.

The initial implementation just delegates to APInt's implementation of
XOR for single element ranges and conservatively returns the full set
otherwise.

Reviewers: nikic, spatel, lebedev.ri

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D76453

1 files changed, 14 insertions, 0 deletions

diff --git a/llvm/lib/IR/ConstantRange.cpp b/llvm/lib/IR/ConstantRange.cpp
index 3d25cb5..b8c5753 100644
--- a/llvm/lib/IR/ConstantRange.cpp
+++ b/llvm/lib/IR/ConstantRange.cpp
@@ -802,6 +802,8 @@ ConstantRange ConstantRange::binaryOp(Instruction::BinaryOps BinOp,
     return binaryAnd(Other);
   case Instruction::Or:
     return binaryOr(Other);
+  case Instruction::Xor:
+    return binaryXor(Other);
   // Note: floating point operations applied to abstract ranges are just
   // ideal integer operations with a lossy representation
   case Instruction::FAdd:
@@ -1211,6 +1213,18 @@ ConstantRange::binaryOr(const ConstantRange &Other) const {
   return getNonEmpty(std::move(umax), APInt::getNullValue(getBitWidth()));
 }
 
+ConstantRange ConstantRange::binaryXor(const ConstantRange &Other) const {
+  if (isEmptySet() || Other.isEmptySet())
+    return getEmpty();
+
+  // Use APInt's implementation of XOR for single element ranges.
+  if (isSingleElement() && Other.isSingleElement())
+    return {*getSingleElement() ^ *Other.getSingleElement()};
+
+  // TODO: replace this with something less conservative
+  return getFull();
+}
+
 ConstantRange
 ConstantRange::shl(const ConstantRange &Other) const {
   if (isEmptySet() || Other.isEmptySet())