On 8/8/25 21:18, Richard Sandiford wrote:
+(define_insn "*aarch64_cb<code><mode>"
+ [(set (pc) (if_then_else
+ (INT_CMP
+ (match_operand:GPI 0 "register_operand" "r")
+ (match_operand:GPI 1
+ "<cmpbr_imm_predicate>" "r<cmpbr_imm_constraint>"))
An alternative to adding a new code attribute would be to embed
the immediate constraint in the predicate name, to ensure that
the two don't get out of sync. We've done that for things like
aarch64_sve_cmp_<sve_imm_con>_operand. It does make the predicate
name slightly less mnemonic though...
Good idea. I was uncomfortable having to replicate the range info twice, much less the
third time into the predicate.
The other idea I had was a match_operator which also examines XEXP (op, 1). But that
means we lose the macro expansion of the strings in the body. %m/%M doesn't quite work
for CMPBR, because it emits cs/cc instead of hs/lo. I suspect that all assemblers would
accept either for existing uses (B.cond, CCMP, CSEL, CSET), but I didn't want to try.
r~
