On Mon, 19 Jan 2015, Maciej W. Rozycki wrote: > > sorry i might be missing something but why do you think this is an > > important bug fix that should go into 3.19? the way i read the code it > > seems that it can't go wrong at the moment. > > We shouldn't be using trapping instructions for address calculation. > These macros have been wrong since the beginning, the MSA instructions > they correspond to do not trigger an exception on an integer overflow in > address calculation (none of the MIPS instruction does). And BTW, it is a bug in GAS too, that it does not accept ADDI for R6 -- it should treat the instruction as a macro and expand it to an equivalent LI + ADD sequence (using $at or `rd', if available, as a temporary to store the immediate). Similarly to how microMIPS DADDI is handled for example (where the hardware instruction has an unusually limited range of the immediate argument, however GAS accepts any 16-bit). Maciej
