[mlir] 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, 1 insertions, 1 deletions

diff --git a/mlir/lib/Conversion/ControlFlowToLLVM/ControlFlowToLLVM.cpp b/mlir/lib/Conversion/ControlFlowToLLVM/ControlFlowToLLVM.cpp
index e7d7873ab5cd..2c84e0b25c55 100644
--- a/mlir/lib/Conversion/ControlFlowToLLVM/ControlFlowToLLVM.cpp
+++ b/mlir/lib/Conversion/ControlFlowToLLVM/ControlFlowToLLVM.cpp
@@ -66,7 +66,7 @@ struct AssertOpLowering : public ConvertOpToLLVMPattern<cf::AssertOp> {
 
     // Generate IR to call `abort`.
     Block *failureBlock = rewriter.createBlock(opBlock->getParent());
-    rewriter.create<LLVM::CallOp>(loc, abortFunc, llvm::None);
+    rewriter.create<LLVM::CallOp>(loc, abortFunc, std::nullopt);
     rewriter.create<LLVM::UnreachableOp>(loc);
 
     // Generate assertion test.