So, there exists registers which are reserved denoted by the Machine Register Info :: getReserved field. I am wondering if these registers are reserved or preserved?
I have come across a case where a reserved register was used. Namely it’s in “llvm\test\CodeGen\X86\2009-04-27-CoalescerAssert.ll” where the reserved register ESP (54) in block “bb98.fragment” on line 854. Is this use of a reserved register a mistake or not?