This option instructs the assembler to report when the assembler outputs an encoding that was not directly requested in the source code. This can happen when the assembler:
uses a pseudo-instruction that is not available in other assemblers, for example
outputs an encoding that does not directly match the instruction mnemonic, for example if the assembler outputs the
MVNencoding when assembling the
inserts additional instructions where necessary for instruction syntax semantics, for example the assembler can insert a missing
ITinstruction before a conditional Thumb instruction.