[mlir] Remove unused local variables (NFC) (#140990)

Author: kazutakahirata

mlir/lib/IR/AffineMap.cpp

@@ -604,7 +604,6 @@ size_t AffineMap::getNumOfZeroResults() const {
 }
 
 AffineMap AffineMap::dropZeroResults() {
-  auto exprs = llvm::to_vector(getResults());
   SmallVector<AffineExpr> newExprs;
 
   for (auto expr : getResults()) {

mlir/lib/Target/LLVMIR/ModuleImport.cpp

@@ -756,7 +756,6 @@ convertProfileSummaryModuleFlagValue(ModuleOp mlirModule,
 
   // Build ModuleFlagProfileSummaryAttr by sequentially fetching elements in
   // a fixed order: format, total count, etc.
-  SmallVector<Attribute> profileSummary;
   std::optional<ProfileSummaryFormatKind> format = convertProfileSummaryFormat(
       mlirModule, llvmModule, mdTuple->getOperand(summayIdx++));
   if (!format.has_value())

mlir/lib/Target/SPIRV/Serialization/Serializer.cpp

@@ -996,7 +996,6 @@ uint32_t Serializer::prepareConstantFp(Location loc, FloatAttr floatAttr,
 
   auto resultID = getNextID();
   APFloat value = floatAttr.getValue();
-  APInt intValue = value.bitcastToAPInt();
 
   auto opcode =
       isSpec ? spirv::Opcode::OpSpecConstant : spirv::Opcode::OpConstant;