Hi all,
I'm trying to add an alternative to an existing insn foobar:
(define_insn "foobar"
[(set (match_operand ...)
(match_operand ...))]
""
"@
foo
bar
#")
Since the asm output depends on the operands in a non-trivial way which isn't
easily solved via iterators, I went for a general C function and came up with:
(define_insn "foobar"
[(set (match_operand ...)
(match_operand ...))]
""
"@
foo
* return foobar_helper (operands[0], operands[1]);
bar
#"
[(set_attr_alternative "mnemonic" [(const_string "foo")
(const_string "specialcase")
(const_string "bar")
(const_string "unknown")])])
If there exist a lot of alternatives, then setting the mnemonic attribute like
this feels repetitive and is error prone. Furthermore, if there exists no
other insn with an output template containing foo/bar, then I would have to
declare foo/bar via
(define_attr "mnemonic" "...,foo,bar,..." (const_string "unknown"))
which again is repetitive. Thus, I'm wondering if there exists a more elegant
way to achieve this? Ultimately, I would like to set the mnemonic
attribute only manually for the alternative which is implemented via C
code and let the mnemonic attribute for the remaining alternatives be
set automagically. Not sure whether this is supported?
If all fails, I have another idea how to solve this by utilizing PRINT_OPERAND.
However, now I'm curious whether my current attempt is feasible or not.
Cheers,
Stefan
