On 01/19/2015 07:25 PM, Maciej W. Rozycki wrote:

On Mon, 19 Jan 2015, Maciej W. Rozycki wrote:

quoted

quoted

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

CC'ing Matthew

-- 
markos