Robin Dapp wrote:
> * config/s390/s390.c (preferred_la_operand_p): Do not use
> LA with base and index on z13 or later.
The code just before your change reads:
/* Avoid LA instructions with index register on z196; it is
preferable to use regular add instructions when possible.
Starting with zEC12 the la with index register is "uncracked"
again. */
if (addr.indx && s390_tune == PROCESSOR_2817_Z196)
return false;
But on zEC12 LA works pretty much the same as on z13/z14, it is
indeed not cracked, but still a 2-cycle instruction when using
an index register. So I guess the change really should apply
to zEC12 as well, and this could be as simple as changing the
above line to:
if (addr.indx && s390_tune >= PROCESSOR_2817_Z196)
(Note that "addr.base && addr.indx" is the same as just checking
for addr.indx, since s390_decompose_address will never fill in
*just* an index.)
Bye,
Ulrich
--
Dr. Ulrich Weigand
GNU/Linux compilers and toolchain
ulrich.weig...@de.ibm.com
