[mlir] Remove unused "using" (NFC)

Identified by misc-unused-using-decls.

mlir/lib/Analysis/AffineAnalysis.cpp

@@ -32,8 +32,6 @@
 
 using namespace mlir;
 
-using llvm::dbgs;
-
 /// Get the value that is being reduced by `pos`-th reduction in the loop if
 /// such a reduction can be performed by affine parallel loops. This assumes
 /// floating-point operations are commutative. On success, `kind` will be the

mlir/lib/Dialect/Linalg/Transforms/Fusion.cpp

@@ -38,8 +38,6 @@
 using namespace mlir;
 using namespace mlir::linalg;
 
-using llvm::dbgs;
-
 /// Implements a simple high-level fusion pass on linalg structured operations.
 ///
 /// In each block, linalg ops are processed in reverse textual order.

mlir/lib/Dialect/Linalg/Transforms/Vectorization.cpp

@@ -38,8 +38,6 @@
 using namespace mlir;
 using namespace mlir::linalg;
 
-using llvm::dbgs;
-
 #define DEBUG_TYPE "linalg-vectorization"
 
 #define DBGS() (llvm::dbgs() << '[' << DEBUG_TYPE << "] ")

mlir/lib/IR/MLIRContext.cpp

@@ -43,8 +43,6 @@
 using namespace mlir;
 using namespace mlir::detail;
 
-using llvm::hash_combine;
-
 //===----------------------------------------------------------------------===//
 // MLIRContext CommandLine Options
 //===----------------------------------------------------------------------===//

mlir/lib/Parser/AffineParser.cpp

@@ -17,9 +17,7 @@
 
 using namespace mlir;
 using namespace mlir::detail;
-using llvm::MemoryBuffer;
 using llvm::SMLoc;
-using llvm::SourceMgr;
 
 namespace {
 

mlir/lib/Parser/Lexer.cpp

@@ -20,7 +20,6 @@
 using namespace mlir;
 
 using llvm::SMLoc;
-using llvm::SourceMgr;
 
 // Returns true if 'c' is an allowable punctuation character: [$._-]
 // Returns false otherwise.

mlir/tools/mlir-linalg-ods-gen/mlir-linalg-ods-yaml-gen.cpp

@@ -30,7 +30,6 @@
 using namespace mlir;
 
 using llvm::yaml::Input;
-using llvm::yaml::IO;
 using llvm::yaml::MappingTraits;
 using llvm::yaml::ScalarEnumerationTraits;
 using llvm::yaml::ScalarTraits;

mlir/tools/mlir-tblgen/DirectiveCommonGen.cpp

@@ -22,7 +22,6 @@ using llvm::Clause;
 using llvm::ClauseVal;
 using llvm::raw_ostream;
 using llvm::RecordKeeper;
-using llvm::Twine;
 
 // LLVM has multiple places (Clang, Flang, MLIR) where information about
 // the directives (OpenMP/OpenACC), and clauses are needed. It is good software

mlir/tools/mlir-tblgen/SPIRVUtilsGen.cpp

@@ -40,7 +40,6 @@ using llvm::SmallVector;
 using llvm::SMLoc;
 using llvm::StringMap;
 using llvm::StringRef;
-using llvm::Twine;
 using mlir::tblgen::Attribute;
 using mlir::tblgen::EnumAttr;
 using mlir::tblgen::EnumAttrCase;