more than 10 operands in `asm', but there aren't.

[Robert Harley]

I thought the "+" constraint would solve my problem with inline asm
complaining about too many operands.  Here's the first example I tried:

  asm ("adds    %0, %0, %4
        adcs    %1, %1, %5
        adcs    %2, %2, %6
        adc     %3, %3, %7"
      : "+r" (x0), "+r" (x1), "+r" (x2), "+r" (x3)
      : "r" (y0), "r" (y1), "r" (y2), "r" (y3)
      : "cc"
      );

to add two 128-bit numbers on ARM.  But it gives the:

  more than 10 operands in `asm'


error even though there are only 8 operands.  =:-(

Presumably the 8 are getting expanded internally into 12 before the
check is done.  Sure enough in stmt.c, the expand_asm_operands()
function does:

  ninputs += ninout;
  if (ninputs + noutputs > MAX_RECOG_OPERANDS)
    {
      error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
      return;
    }


Adding 96-bits numbers should be OK:

  asm volatile (
       "adds    %0, %0, %3
        adcs    %1, %1, %4
        adc     %2, %2, %5"
      : "+r" (x0), "+r" (x1), "+r" (x2)
      : "r" (y0), "r" (y1), "r" (y2)
      : "cc"
      );

This goes through fine.  But then if I break it by accessing
non-existant operands %6, %7 or %8, say like this:

  asm volatile (
       "adds    %0, %0, %3
        adcs    %1, %1, %4
        adc     %2, %2, %8"
      : "+r" (x0), "+r" (x1), "+r" (x2)
      : "r" (y0), "r" (y1), "r" (y2)
      : "cc"
      );

then it goes through as well and produces bogus code instead of the:

  invalid `asm': operand number out of range


error message.


It seems that MAX_RECOG_OPERANDS should be split into two values, one
for the actual number of operands (<= 10) and one for the expanded
number (<= 20 I suppose), so that the good example compiles and the
broken one fails instead of vice-versa.

Bye,
  Rob.