[llvm] Use std::nullopt instead of None (NFC)

This patch mechanically replaces None with std::nullopt where the
compiler would warn if None were deprecated.  The intent is to reduce
the amount of manual work required in migrating from Optional to
std::optional.

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

1 files changed, 6 insertions, 6 deletions

diff --git a/llvm/lib/Support/KnownBits.cpp b/llvm/lib/Support/KnownBits.cpp
index 9f34405..c62a1a3 100644
--- a/llvm/lib/Support/KnownBits.cpp
+++ b/llvm/lib/Support/KnownBits.cpp
@@ -335,13 +335,13 @@ Optional<bool> KnownBits::eq(const KnownBits &LHS, const KnownBits &RHS) {
     return Optional<bool>(LHS.getConstant() == RHS.getConstant());
   if (LHS.One.intersects(RHS.Zero) || RHS.One.intersects(LHS.Zero))
     return Optional<bool>(false);
-  return None;
+  return std::nullopt;
 }
 
 Optional<bool> KnownBits::ne(const KnownBits &LHS, const KnownBits &RHS) {
   if (Optional<bool> KnownEQ = eq(LHS, RHS))
     return Optional<bool>(!*KnownEQ);
-  return None;
+  return std::nullopt;
 }
 
 Optional<bool> KnownBits::ugt(const KnownBits &LHS, const KnownBits &RHS) {
@@ -351,13 +351,13 @@ Optional<bool> KnownBits::ugt(const KnownBits &LHS, const KnownBits &RHS) {
   // LHS >u RHS -> true if umin(LHS) > umax(RHS)
   if (LHS.getMinValue().ugt(RHS.getMaxValue()))
     return Optional<bool>(true);
-  return None;
+  return std::nullopt;
 }
 
 Optional<bool> KnownBits::uge(const KnownBits &LHS, const KnownBits &RHS) {
   if (Optional<bool> IsUGT = ugt(RHS, LHS))
     return Optional<bool>(!*IsUGT);
-  return None;
+  return std::nullopt;
 }
 
 Optional<bool> KnownBits::ult(const KnownBits &LHS, const KnownBits &RHS) {
@@ -375,13 +375,13 @@ Optional<bool> KnownBits::sgt(const KnownBits &LHS, const KnownBits &RHS) {
   // LHS >s RHS -> true if smin(LHS) > smax(RHS)
   if (LHS.getSignedMinValue().sgt(RHS.getSignedMaxValue()))
     return Optional<bool>(true);
-  return None;
+  return std::nullopt;
 }
 
 Optional<bool> KnownBits::sge(const KnownBits &LHS, const KnownBits &RHS) {
   if (Optional<bool> KnownSGT = sgt(RHS, LHS))
     return Optional<bool>(!*KnownSGT);
-  return None;
+  return std::nullopt;
 }
 
 Optional<bool> KnownBits::slt(const KnownBits &LHS, const KnownBits &RHS) {