[CIR] Fix unused variable and covered switch default warnings

Author: bcardosolopes

clang/lib/CIR/CodeGen/CIRGenCXX.cpp

@@ -45,8 +45,6 @@ static void buildDeclInit(CIRGenFunction &CGF, const VarDecl *D,
     llvm_unreachable("scalar evaluation NYI");
   case TEK_Complex:
     llvm_unreachable("complext evaluation NYI");
-  default:
-    llvm_unreachable("bad evaluation kind");
   }
 }
 

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp

@@ -1164,8 +1164,6 @@ class CIRGlobalOpLowering
         // Failed to use a compact attribute as an initializer:
         // initialize elements individually.
         if (!(init = lowerConstArrayAttr(constArr, getTypeConverter()))) {
-          auto eltTy =
-              constArr.getType().cast<mlir::cir::ArrayType>().getEltType();
           setupRegionInitializedLLVMGlobalOp(op, rewriter);
           rewriter.create<mlir::LLVM::ReturnOp>(
               op->getLoc(), lowerCirAttrAsValue(constArr, op->getLoc(),