[Sbcl-devel] return type not fixed values

[Stephan F. <def...@go...>]

Hi,

for many functions in the new allocation branch I get the compiler note

;     (SB-GMP::DEFGMPFUN SB-GMP:MPZ-ADD
;         (SB-GMP::A SB-GMP::B)
;       (SB-GMP::WITH-ALLOCATED-RESULTS ((SB-GMP::RESULT (1+ #)))
;         (SB-GMP::WITH-MPZ-VARS ((SB-GMP::A SB-GMP::GA) (SB-GMP::B 
SB-GMP::GB))
;           (SB-GMP::__GMPZ_ADD (ADDR SB-GMP::RESULT) (ADDR SB-GMP::GA)
;            (ADDR SB-GMP::GB)))))
; --> PROGN DEFUN PROGN
; ==>
;   (SB-IMPL::%DEFUN 'SB-GMP:MPZ-ADD
;                    (SB-INT:NAMED-LAMBDA SB-GMP:MPZ-ADD
;                        (SB-GMP::A SB-GMP::B)
;                      (DECLARE (OPTIMIZE (SPEED 3) (SPACE 3))
;                               (TYPE INTEGER SB-GMP::A SB-GMP::B))
;                      (BLOCK SB-GMP:MPZ-ADD
;                        (SB-GMP::WITH-ALLOCATED-RESULTS (#)
;                          (SB-GMP::WITH-MPZ-VARS #
;                            #))))
;                    NIL
;                    '(SB-C:LAMBDA-WITH-LEXENV NIL NIL NIL (SB-GMP::A 
SB-GMP::B)
;                      (DECLARE (OPTIMIZE (SPEED 3) (SPACE 3))
;                               (TYPE INTEGER SB-GMP::A SB-GMP::B))
;                      (BLOCK SB-GMP:MPZ-ADD
;                        (SB-GMP::WITH-ALLOCATED-RESULTS (#)
;                          (SB-GMP::WITH-MPZ-VARS #
;                            #))))
;                    (SB-C:SOURCE-LOCATION))
;
; note: Return type not fixed values, so can't use known return convention:
;   NIL


One such function is

(defgmpfun mpz-add (a b)
   (with-allocated-results ((result (1+ (max (blength a)
                                             (blength b)))))
     (with-mpz-vars ((a ga) (b gb))
       (__gmpz_add (addr result) (addr ga) (addr gb)))))

The defgmpfun expansion is

(PROGN
  (DECLAIM (SB-EXT:MAYBE-INLINE MPZ-ADD))
  (DEFUN MPZ-ADD (A B)
    (DECLARE (OPTIMIZE (SPEED 3) (SPACE 3))
             (TYPE INTEGER A B))
    (WITH-ALLOCATED-RESULTS ((RESULT (1+ (MAX (BLENGTH A) (BLENGTH B)))))
      (WITH-MPZ-VARS ((A GA) (B GB))
        (__GMPZ_ADD (ADDR RESULT) (ADDR GA) (ADDR GB))))))

and the inner expanded part is as follows

(LET ((#:RESULT949 (%ALLOCATE-BIGNUM (1+ (MAX (BLENGTH A) (BLENGTH B))))))
   (SB-SYS:WITHOUT-GCING
     (WITH-ALIEN ((RESULT (STRUCT GMPINT)))
       (SETF (SLOT RESULT 'MP_ALLOC) (1+ (MAX (BLENGTH A) (BLENGTH B)))
             (SLOT RESULT 'MP_SIZE) 0
             (SLOT RESULT 'MP_D) (BIGNUM-DATA-SAP #:RESULT949))
       (WITH-MPZ-VARS ((A GA) (B GB))
         (__GMPZ_ADD (ADDR RESULT) (ADDR GA) (ADDR GB)))
       (LET ((#:NRESULT950
              (IF (MINUSP (SLOT RESULT 'MP_SIZE))
                  (-
                   (%NORMALIZE-BIGNUM
                    (DATA-SAP-BIGNUM (ALIEN-SAP (SLOT RESULT 'MP_D)))
                    (SLOT RESULT 'MP_ALLOC)))
                  (%NORMALIZE-BIGNUM
                   (DATA-SAP-BIGNUM (ALIEN-SAP (SLOT RESULT 'MP_D)))
                   (SLOT RESULT 'MP_ALLOC)))))
         (VALUES #:NRESULT950)))))

Values appears to be quite fixed (this is a simple instance, there are 
other functions with two return values). What do I have to do to make 
SBCL be aware of the fixed values (and what is this NIL in the compiler 
note)?

Many thanks and best regards,
Stephan