Hi,
The LAST_INSN_CODE is used to mark the last instruction code valid for a
particular architecture (e.g., For ARM the value of LAST_INSN_CODE is 3799).
Also this code (i.e., 3799) is used by a predicated instruction (e.g., for ARM
this code is used by predicated version of arm_usatsihi => {*p arm_usatsihi}).
However, the LAST_INSN_CODE macro is used by lra, recog and tree-vect-stmts to
dimension various arrays which may lead to various errors.
For example, when calling preprocess_insn_constraints (recog.c:2444), the
compilation may go berserk when evaluating "if
(this_target_recog->x_op_alt[icode])" line when icode is exactly the
LAST_INSN_CODE as "this_target_recog->x_op_alt" is dimensioned up to
LAST_INSN_CODE (recog.h:397).
A possible solution is having the LAST_INSN_CODE value to be exactly the value
returned by get_num_isns_codes() (gencodes.c:89). Alternatively is to use
LAST_INSN_CODE+1 when defining an array.
Please can someone confirm my observation. And what will be the best solution
for this.
Thanks,
Claudiu
