Am 10.06.2010 um 15:27 schrieb Ian Lance Taylor:
> Boris Boesler <baem...@gmx.de> writes:
>
>> I get an internal compiler error with gcc-4.2.1 and my own back-end
>> when I support conditional execution:
>>
>> ../build/gcc/cc1 -Wall -O1 -o bug.O1.s bug.c
>>
>> bug.c: In function ‘cond_assign_les0’:
>> bug.c:13: internal compiler error: in elim_reg_cond, at flow.c:3486
>
> What is 'x' when that error occurs? From a quick glance at the code
> that can only happen if your backend has somehow built a conditional
> with a component which is not a conditional.
I don't really know what 'x' is (but its code is 0/UnKnown); it's generated
by GCC from my conditional execution specification, which I derived from the
manual and the ARM backend:
;;
(define_attr "predicable" "no,yes" (const_string "no"))
;; True if this operator is valid for predication.
(define_special_predicate "predicate_operator"
;; fails in tests (match_code "eq,ne,le,lt,ge,gt,geu,gtu,leu,ltu")
(match_code "eq,ne") ;; works
;; fails in tests (match_code "le")
)
(define_cond_exec
[(match_operator 0 "predicate_operator"
[(match_operand 1 "cc_register" "")
(const_int 0)])]
" ! TARGET_DONT_USE_CONDITIONAL_EXECUTION "
;; this sets a C string, that will be emitted in instructions by %?
"%J0"
)
(define_insn "addsi3_mem"
[(set (match_operand:SI 0 "memory_operand" "=m")
(plus:SI (match_operand:SI 1 "memory_operand" "%m")
(match_operand:SI 2 "immediate_operand" " i")))
]
""
"ADDI%?\t%0, %1, %2"
[(set_attr "length" "4")
(set_attr "predicable" "yes")
]
)
This works for the predicate operators "eq,ne". Is there anything
wrong with it? Maybe the ARM backend does something that I haven't seen.
> Note that all this code is gone in current gcc. It was removed in gcc
> 4.3, replaced by the data flow framework.
Ok, then I will try to move to gcc 4.3
Boris
