[M3devel] Strange behavior in recent CM3-compiled code...
Jay
jay.krell at cornell.edu
Tue Jun 16 11:16:39 CEST 2009
I haven't figured it out, but:
Here is the code for the Fmt.Bool:
.L6:
; assume the parameter to Fmt.Bool is TRUE, by
; storing 1 in the parameter place
movq $1, 16(%rsp)
; do a bunch of stuff, no need to understand..
movq 32(%rsp), %rax
testq %rax, %rax
je .L7
movq 32(%rsp), %rax
testb $1, %al
jne .L8
movq 32(%rsp), %rax
movq 312+MM_Main(%rip), %rdx
movq -8(%rax), %rax
salq $43, %rax
shrq $44, %rax
; at this point, between $rdx and $rax, one is
; typecode of the object, one is the typecode of the type
; they compare equal
cmpq %rdx, %rax
; This is not taken.
jne .L9
; This is taken.
jmp .L7
.L8:
; This does not run.
movq 312+MM_Main(%rip), %rax
cmpq $3, %rax
je .L7
.L9:
; Had the expression resolved to FALSE, this would be
; where FALSE is passed to Fmt.Bool
movq $0, 16(%rsp)
.L7:
movq 16(%rsp), %rdi
call Fmt__Bool at PLT
And here is the code for the IF:
.L11:
; just gloss over this part..
movq 40(%rsp), %rax
testq %rax, %rax
je .L12
movq 40(%rsp), %rax
testb $1, %al
jne .L13
movq 40(%rsp), %rax
movq 312+MM_Main(%rip), %rdx
movq -8(%rax), %rax
salq $43, %rax
shrq $44, %rax
; again at this point, we have the typecodes, and they compare equal
cmpq %rdx, %rax
; This is not taken.
jne .L14
.L13:
; At this point things have gone wrong.
; The Fmt.Bool path did not compare the typecode to 3.
; after the jne, there should have been a jmp to I guess .L12.
movq 312+MM_Main(%rip), %rax
cmpq $3, %rax
jne .L14
.L12:
.stabn 68,0,19,.LM9-.LFBB2
.LM9:
leaq 128+L_1(%rip), %rdi
call Main__PutLn at PLT
jmp .L15
.p2align 4,,10
.p2align 3
.L14:
.stabn 68,0,21,.LM10-.LFBB2
.LM10:
leaq 168+L_1(%rip), %rdi
call Main__PutLn at PLT
Thanks for the small test case!
- Jay
From: jay.krell at cornell.edu
To: mika at async.caltech.edu
Date: Tue, 16 Jun 2009 08:50:02 +0000
CC: m3devel at elegosoft.com
Subject: Re: [M3devel] Strange behavior in recent CM3-compiled code...
Well, the number 3 is REFANY_typecode.
I need to compare the if code to the printing code though..
- Jay
From: jay.krell at cornell.edu
To: mika at async.caltech.edu
CC: m3devel at elegosoft.com
Subject: RE: [M3devel] Strange behavior in recent CM3-compiled code...
Date: Tue, 16 Jun 2009 08:44:21 +0000
Cool.
Here is a smaller repro, on birch AMD64_LINUX.
The problem is not the AND, the problem is the IF.
MODULE Main;
IMPORT IO, Fmt;
PROCEDURE PutLn(what : TEXT) =
BEGIN IO.Put(what & "\n") END PutLn;
TYPE
Pair = REF RECORD
rest : REFANY;
END;
VAR
t := NEW(Pair, rest := NEW(Pair, rest := NIL));
BEGIN
PutLn("ISTYPE(t.rest,Pair)? " & Fmt.Bool(ISTYPE(t.rest,Pair)));
IF ISTYPE(t.rest,Pair) THEN
PutLn("in IF clause...")
ELSE
PutLn("in ELSE clause...")
END
END Main.
Tony this is presumably your type tagging changes??
The problem in the code I think is the compare to the number 3.
.L13:
movq 312+MM_Main(%rip), %rax
cmpq $3, %rax <====
jne .L14
.L12:
.stabn 68,0,19,.LM9-.LFBB2
.LM9:
leaq 128+L_1(%rip), %rdi
call Main__PutLn at PLT
jmp .L15
.p2align 4,,10
.p2align 3
.L14:
.stabn 68,0,21,.LM10-.LFBB2
.LM10:
leaq 168+L_1(%rip), %rdi
call Main__PutLn at PLT
What is that for?
It comes right from the IL:
(118) set_source_line
source line 17
(119) import_procedure
procedure RTHooks__CheckLoadTracedRef nparams 0x1 rettype 0xd
(120) declare_param
param M3_Af40ku_ref type 0xb typeid 0x1c1c45e6 bytesize 0x40 alignment 0x40 in
_memory 0x0 up_level 0x0
mode 0x11 (DImode)
(121) set_runtime_proc
(122) load
m3cg_load (MM_Main): offset 0x640, convert 0xb -> 0xb
(123) store
store (noname) offset 0x0 src_t 0xb dst_t 0xb
(124) load_nil
(125) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(126) if_eq
(127) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(128) loophole
(129) load_integer
integer 0x1
(130) and
(131) if_true
(132) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(133) load_indirect
load address offset 0xffffffffffffffc0 src_t 0x7 dst_t 0x7
(134) extract_mn
(135) if_false
(136) start_call_direct
start call procedure RTHooks__CheckLoadTracedRef, level 0x0, type 0xd
(137) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(138) pop_param
pop param type 0xb
(139) call_direct
call procedure RTHooks__CheckLoadTracedRef, type 0xd
(140) set_label
(141) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(142) load_indirect
load address offset 0x0 src_t 0xb dst_t 0xb
(143) store
store (noname) offset 0x0 src_t 0xb dst_t 0xb
(144) load_nil
(145) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(146) if_eq
(147) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(148) loophole
(149) load_integer
integer 0x1
(150) and
(151) if_true
(152) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(153) load_indirect
load address offset 0xffffffffffffffc0 src_t 0x7 dst_t 0x7
(154) extract_mn
(155) if_false
(156) start_call_direct
start call procedure RTHooks__CheckLoadTracedRef, level 0x0, type 0xd
(157) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(158) pop_param
pop param type 0xb
(159) call_direct
call procedure RTHooks__CheckLoadTracedRef, type 0xd
(160) set_label
(161) load_integer
integer 0x1
(162) declare_temp
temp var type 0x7 size 0x40 alignment 0x40
(163) store
store (noname) offset 0x0 src_t 0x7 dst_t 0x7
(164) load_nil
(165) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(166) if_eq
(167) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(168) loophole
(169) load_integer
integer 0x1
(170) and
(171) if_true
(172) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(173) load_indirect
load address offset 0xffffffffffffffc0 src_t 0x7 dst_t 0x7
(174) extract_mn
(175) load
m3cg_load (MM_Main): offset 0x9c0, convert 0x7 -> 0x7
(176) if_eq
(177) jump
(178) set_label
(179) load_integer
integer 0x3
(180) load
m3cg_load (MM_Main): offset 0x9c0, convert 0x7 -> 0x7
(181) if_eq
(182) set_label
(183) load_integer
integer 0x0
(184) store
store (noname) offset 0x0 src_t 0x7 dst_t 0x7
(185) set_label
(186) import_procedure
procedure Fmt__Bool nparams 0x1 rettype 0xb
(187) declare_param
param M3_AicXUJ_b type 0x0 typeid 0x1e59237d bytesize 0x8 alignment 0x8 in_mem
ory 0x0 up_level 0x0
mode 0xe ()
(188) start_call_direct
start call procedure Fmt__Bool, level 0x0, type 0xb
(189) load
m3cg_load (noname): offset 0x0, convert 0x7 -> 0x7
(190) pop_param
pop param type 0x0
(191) call_direct
call procedure Fmt__Bool, type 0xb
(192) store
store (noname) offset 0x0 src_t 0xb dst_t 0xb
(193) start_call_direct
start call procedure RTHooks__Concat, level 0x0, type 0xb
(194) load_address
load address (L_1) offset 0x280
(195) pop_param
pop param type 0xb
(196) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(197) pop_param
pop param type 0xb
(198) call_direct
call procedure RTHooks__Concat, type 0xb
(199) store
store (noname) offset 0x0 src_t 0xb dst_t 0xb
(200) start_call_direct
start call procedure Main__PutLn, level 0x0, type 0xd
(201) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(202) pop_param
pop param type 0xb
(203) call_direct
call procedure Main__PutLn, type 0xd
(204) set_source_line
source line 18
(205) load
m3cg_load (MM_Main): offset 0x640, convert 0xb -> 0xb
(206) store
store (noname) offset 0x0 src_t 0xb dst_t 0xb
(207) load_nil
(208) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(209) if_eq
(210) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(211) loophole
(212) load_integer
integer 0x1
(213) and
(214) if_true
(215) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(216) load_indirect
load address offset 0xffffffffffffffc0 src_t 0x7 dst_t 0x7
(217) extract_mn
(218) if_false
(219) start_call_direct
start call procedure RTHooks__CheckLoadTracedRef, level 0x0, type 0xd
(220) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(221) pop_param
pop param type 0xb
(222) call_direct
call procedure RTHooks__CheckLoadTracedRef, type 0xd
(223) set_label
(224) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(225) load_indirect
load address offset 0x0 src_t 0xb dst_t 0xb
(226) store
store (noname) offset 0x0 src_t 0xb dst_t 0xb
(227) load_nil
(228) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(229) if_eq
(230) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(231) loophole
(232) load_integer
integer 0x1
(233) and
(234) if_true
(235) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(236) load_indirect
load address offset 0xffffffffffffffc0 src_t 0x7 dst_t 0x7
(237) extract_mn
(238) if_false
(239) start_call_direct
start call procedure RTHooks__CheckLoadTracedRef, level 0x0, type 0xd
(240) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(241) pop_param
pop param type 0xb
(242) call_direct
call procedure RTHooks__CheckLoadTracedRef, type 0xd
(243) set_label
(244) load_nil
(245) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(246) if_eq
(247) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(248) loophole
(249) load_integer
integer 0x1
(250) and
(251) if_true
(252) load
m3cg_load (noname): offset 0x0, convert 0xb -> 0xb
(253) load_indirect
load address offset 0xffffffffffffffc0 src_t 0x7 dst_t 0x7
(254) extract_mn
(255) load
m3cg_load (MM_Main): offset 0x9c0, convert 0x7 -> 0x7
(256) if_ne
(257) set_label
(258) load_integer
integer 0x3 <=====
(259) load
m3cg_load (MM_Main): offset 0x9c0, convert 0x7 -> 0x7
(260) if_ne
(261) set_label
(262) set_source_line
source line 19
(263) start_call_direct
start call procedure Main__PutLn, level 0x0, type 0xd
(264) load_address
load address (L_1) offset 0x400
(265) pop_param
pop param type 0xb
(266) call_direct
call procedure Main__PutLn, type 0xd
(267) jump
(268) set_label
(269) set_source_line
source line 21
(270) start_call_direct
start call procedure Main__PutLn, level 0x0, type 0xd
(271) load_address
load address (L_1) offset 0x540
(272) pop_param
pop param type 0xb
(273) call_direct
call procedure Main__PutLn, type 0xd
(274) set_label
(275) set_label
(276) load_address
load address (MM_Main) offset 0x0
(277) exit_proc
(278) free_temp
(279) free_temp
(280) free_temp
(281) free_temp
(282) free_temp
(283) end_procedure
procedure Main_M3
(284) comment
comment: `global constant type descriptor'
(285) declare_record
record id 0xffffffff, fields 0x0, size 0x940
(286) comment
comment: `global data type descriptor'
I'll dig a bit more.
- Jay
> To: jay.krell at cornell.edu
> Date: Tue, 16 Jun 2009 00:59:10 -0700
> From: mika at async.caltech.edu
> CC: m3devel at elegosoft.com
> Subject: Re: [M3devel] Strange behavior in recent CM3-compiled code...
>
> This small example exhibits it!
>
> MODULE Main;
> IMPORT IO, Fmt;
>
> PROCEDURE PutLn(what : TEXT) =
> BEGIN IO.Put(what & "\n") END PutLn;
>
>
> TYPE
> Pair = BRANDED "Pair" REF RECORD
> first, rest : REFANY;
> END;
>
> PROCEDURE Rest(p : Pair) : REFANY =
> BEGIN
> IF p = NIL THEN RETURN NIL ELSE RETURN p.rest END
> END Rest;
>
> VAR
> t := NEW(Pair, first := "first",
> rest := NEW(Pair, first := "second",
> rest := NIL));
>
> BEGIN
> PutLn("t.rest # NIL? " & Fmt.Bool(t.rest#NIL));
> PutLn("ISTYPE(t.rest,Pair)? " & Fmt.Bool(ISTYPE(t.rest,Pair)));
> PutLn("Rest(t.rest) = NIL? " & Fmt.Bool(Rest(t.rest)=NIL));
> PutLn("conjunction? " & Fmt.Bool(
> (t.rest # NIL) AND (ISTYPE(t.rest,Pair)) AND (Rest(t.rest) = NIL) ));
> IF (t.rest # NIL) AND (ISTYPE(t.rest,Pair)) AND (Rest(t.rest) = NIL) THEN
> PutLn("in IF clause...")
> ELSE
> PutLn("in ELSE clause...")
> END
> END Main.
>
> Output:
>
> (133)rover:~/testcm3/src>m3build -O
> --- building in ../FreeBSD4 ---
> m3build: missing ../src/m3overrides
> new source -> compiling ../src/Main.m3
> -> linking prog
> (134)rover:~/testcm3/src>../FreeBSD4/prog
> t.rest # NIL? TRUE
> ISTYPE(t.rest,Pair)? TRUE
> Rest(t.rest) = NIL? TRUE
> conjunction? TRUE
> in IF clause...
> (135)rover:~/testcm3/src>cm3 -clean
> --- cleaning ../FreeBSD4 ---
>
> (136)rover:~/testcm3/src>cm3
> --- building in ../FreeBSD4 ---
>
> new source -> compiling Main.m3
> -> linking prog
> (137)rover:~/testcm3/src>../FreeBSD4/prog
> t.rest # NIL? TRUE
> ISTYPE(t.rest,Pair)? TRUE
> Rest(t.rest) = NIL? TRUE
> conjunction? FALSE
> in ELSE clause...
> (138)rover:~/testcm3/src>
>
> Jay writes:
> >--_55f6c801-7d57-4602-a131-dda139b64dfd_
> >Content-Type: text/plain; charset="iso-8859-1"
> >Content-Transfer-Encoding: quoted-printable
> >
> >
> >Kneejerk generic response:
> >
> >=20
> >
> >I don't know the operator precedence. Can you put in parens?
> >
> >Have you looked at the code?
> >
> >Can you mail us a small self contained repro?
> >
> >Can you test it on birch?
> >
> > (That way -- all your files are there and easily gotten/investigated by o=
> >thers.)
> >
> >Optimization enabled? Works without? I know=2C I shouldn't even ask this so=
> >rt of thing without evidence.
> >
> >=20
> >
> > - Jay
> >=20
> >> To: m3devel at elegosoft.com
> >> Date: Tue=2C 16 Jun 2009 00:01:18 -0700
> >> From: mika at async.caltech.edu
> >> CC: mika at camembert.async.caltech.edu
> >> Subject: [M3devel] Strange behavior in recent CM3-compiled code...
> >>=20
> >>=20
> >> Hello everyone=2C
> >>=20
> >> I'm trying to update to the latest CM3 again=2C so that I can get my
> >> Mac working=2C and push my project of migrating a largish codebase
> >> from PM3 to CM3 a little further.
> >>=20
> >> I updated CM3 today from CVS=2C on both my Mac and on a FreeBSD system=2C
> >> and ... my Scheme interpreter broke. Here's what the code looks like=2C
> >> with annotations:
> >>=20
> >> 49 Debug.Out("t.rest =3D NIL? " & Fmt.Bool(t.rest=3DNIL))=3B
> >> 50 Debug.Out("ISTYPE(t.rest=2CT)? " & Fmt.Bool(ISTYPE(t.rest=2CT)))=3B
> >> 51 Debug.Out("Rest(t.rest) =3D NIL? " & Fmt.Bool(Rest(t.rest)=3DNIL))=3B
> >> 52
> >> 53 IF t.rest # NIL AND ISTYPE(t.rest=2CT) AND Rest(t.rest) =3D NIL THEN
> >> 54 Debug.Out("in IF clause...")=3B
> >> 55
> >> 56 IF SymEq(t.first=2C "quote") THEN special :=3D "'"
> >> 57 ELSIF SymEq(t.first=2C "quasiquote") THEN special :=3D "`"
> >> 58 ELSIF SymEq(t.first=2C "unquote") THEN special :=3D "=2C"
> >> 59 ELSIF SymEq(t.first=2C "unquote-splicing") THEN special :=3D "=2C@"
> >> 60 END
> >> 61 ELSE
> >> 62 Debug.Out("in ELSE clause...")
> >> 63 END=3B
> >>=20
> >> all you need to know is that Debug.Out prints out debugging information
> >> to the terminal. What I see is...
> >>=20
> >> t.rest =3D NIL? FALSE
> >> ISTYPE(t.rest=2CT)? TRUE
> >> Rest(t.rest) =3D NIL? TRUE
> >> in ELSE clause...
> >>=20
> >> What gives!?
> >>=20
> >> Note this behavior occurs on both the Mac and on FreeBSD4 with a
> > compiler and runtime bootstrapped today from some previous CM3.
> >> My old CM3 compiler was timestamped... April 30=2C I believe=2C and the
> >> code behaved properly under that one.
> >>=20
> >> I believe I have also tried it both with and without compiler
> >> optimizations.
> >>=20
> >> I find it baffling that so much stuff (mentor!) can work if "AND" isn't
> >> working right. This is the only if statement in many=2C many source files
> >> that seems to be working wrong.
> >>=20
> >> Is it possible I'm missing something?? No I don't think so... here's a mo=
> >re
> >> explicit version:
> >>=20
> >> Debug.Out("t.rest # NIL? " & Fmt.Bool(t.rest#NIL))=3B
> >> Debug.Out("ISTYPE(t.rest=2CT)? " & Fmt.Bool(ISTYPE(t.rest=2CT)))=3B
> >> Debug.Out("Rest(t.rest) =3D NIL? " & Fmt.Bool(Rest(t.rest)=3DNIL))=3B
> >> Debug.Out("conjunction? " & Fmt.Bool(
> >> t.rest # NIL AND ISTYPE(t.rest=2CT) AND Rest(t.rest) =3D NIL ))=3B
> >> IF t.rest # NIL AND ISTYPE(t.rest=2CT) AND Rest(t.rest) =3D NIL THEN
> >> ...
> >>=20
> >> output is:
> >>=20
> >> t.rest # NIL? TRUE
> >> ISTYPE(t.rest=2CT)? TRUE
> >> Rest(t.rest) =3D NIL? TRUE
> >> conjunction? FALSE
> >> in ELSE clause...
> >>=20
> >> TRUE AND TRUE AND TRUE is FALSE??
> >>=20
> >> Note that:=20
> >>=20
> >> VAR q=2C w=2C e :=3D TRUE=3B
> >>=20
> >> Debug.Out("conjunction? " & Fmt.Bool(
> >> q AND w AND e))=3B
> >>=20
> >> results in TRUE (as it should).
> >>=20
> >>=20
> >> Mika
> >>=20
> >
> >--_55f6c801-7d57-4602-a131-dda139b64dfd_
> >Content-Type: text/html; charset="iso-8859-1"
> >Content-Transfer-Encoding: quoted-printable
> >
> ><html>
> ><head>
> ><style>
> >.hmmessage P
> >{
> >margin:0px=3B
> >padding:0px
> >}
> >body.hmmessage
> >{
> >font-size: 10pt=3B
> >font-family:Verdana
> >}
> ></style>
> ></head>
> ><body class=3D'hmmessage'>
> >Kneejerk generic response:<BR>
> > =3B<BR>
> >I don't know the operator precedence. Can you put in parens?<BR>
> >Have you looked at the code?<BR>
> >Can you mail us a small self contained repro?<BR>
> >Can you test it on birch?<BR>
> > =3B (That way -- all your files are there and easily gotten/investigat=
> >ed by others.)<BR>
> >Optimization enabled? Works without? I know=2C I shouldn't even ask this so=
> >rt of thing without evidence.<BR>
> > =3B<BR>
> > =3B- Jay<BR> =3B<BR>>=3B To: m3devel at elegosoft.com<BR>>=3B Dat=
> >e: Tue=2C 16 Jun 2009 00:01:18 -0700<BR>>=3B From: mika at async.caltech.edu=
> ><BR>>=3B CC: mika at camembert.async.caltech.edu<BR>>=3B Subject: [M3devel=
> >] Strange behavior in recent CM3-compiled code...<BR>>=3B <BR>>=3B <BR>=
> >>=3B Hello everyone=2C<BR>>=3B <BR>>=3B I'm trying to update to the l=
> >atest CM3 again=2C so that I can get my<BR>>=3B Mac working=2C and push m=
> >y project of migrating a largish codebase<BR>>=3B from PM3 to CM3 a littl=
> >e further.<BR>>=3B <BR>>=3B I updated CM3 today from CVS=2C on both my =
> >Mac and on a FreeBSD system=2C<BR>>=3B and ... my Scheme interpreter brok=
> >e. Here's what the code looks like=2C<BR>>=3B with annotations:<BR>>=3B=
> > <BR>>=3B 49 Debug.Out("t.rest =3D NIL? " &=3B Fmt.Bool(t.rest=3DNIL))=
> >=3B<BR>>=3B 50 Debug.Out("ISTYPE(t.rest=2CT)? " &=3B Fmt.Bool(ISTYPE(t=
> >.rest=2CT)))=3B<BR>>=3B 51 Debug.Out("Rest(t.rest) =3D NIL? " &=3B Fmt=
> >.Bool(Rest(t.rest)=3DNIL))=3B<BR>>=3B 52<BR>>=3B 53 IF t.rest # NIL AND=
> > ISTYPE(t.rest=2CT) AND Rest(t.rest) =3D NIL THEN<BR>>=3B 54 Debug.Out("i=
> >n IF clause...")=3B<BR>>=3B 55<BR>>=3B 56 IF SymEq(t.first=2C "quote") =
> >THEN special :=3D "'"<BR>>=3B 57 ELSIF SymEq(t.first=2C "quasiquote") THE=
> >N special :=3D "`"<BR>>=3B 58 ELSIF SymEq(t.first=2C "unquote") THEN spec=
> >ial :=3D "=2C"<BR>>=3B 59 ELSIF SymEq(t.first=2C "unquote-splicing") THEN=
> > special :=3D "=2C@"<BR>>=3B 60 END<BR>>=3B 61 ELSE<BR>>=3B 62 Debug.=
> >Out("in ELSE clause...")<BR>>=3B 63 END=3B<BR>>=3B <BR>>=3B all you n=
> >eed to know is that Debug.Out prints out debugging information<BR>>=3B to=
> > the terminal. What I see is...<BR>>=3B <BR>>=3B t.rest =3D NIL? FALSE<=
> >BR>>=3B ISTYPE(t.rest=2CT)? TRUE<BR>>=3B Rest(t.rest) =3D NIL? TRUE<BR>=
> >>=3B in ELSE clause...<BR>>=3B <BR>>=3B What gives!?<BR>>=3B <BR>&g=
> >t=3B Note this behavior occurs on both the Mac and on FreeBSD4 with a<BR>&g=
> >t=3B compiler and runtime bootstrapped today from some previous CM3.<BR>>=
> >=3B My old CM3 compiler was timestamped... April 30=2C I believe=2C and the=
> ><BR>>=3B code behaved properly under that one.<BR>>=3B <BR>>=3B I bel=
> >ieve I have also tried it both with and without compiler<BR>>=3B optimiza=
> >tions.<BR>>=3B <BR>>=3B I find it baffling that so much stuff (mentor!)=
> > can work if "AND" isn't<BR>>=3B working right. This is the only if state=
> >ment in many=2C many source files<BR>>=3B that seems to be working wrong.=
> ><BR>>=3B <BR>>=3B Is it possible I'm missing something?? No I don't thi=
> >nk so... here's a more<BR>>=3B explicit version:<BR>>=3B <BR>>=3B Deb=
> >ug.Out("t.rest # NIL? " &=3B Fmt.Bool(t.rest#NIL))=3B<BR>>=3B Debug.Ou=
> >t("ISTYPE(t.rest=2CT)? " &=3B Fmt.Bool(ISTYPE(t.rest=2CT)))=3B<BR>>=3B=
> > Debug.Out("Rest(t.rest) =3D NIL? " &=3B Fmt.Bool(Rest(t.rest)=3DNIL))=
> >=3B<BR>>=3B Debug.Out("conjunction? " &=3B Fmt.Bool(<BR>>=3B t.rest =
> ># NIL AND ISTYPE(t.rest=2CT) AND Rest(t.rest) =3D NIL ))=3B<BR>>=3B IF t.=
> >rest # NIL AND ISTYPE(t.rest=2CT) AND Rest(t.rest) =3D NIL THEN<BR>>=3B .=
> >..<BR>>=3B <BR>>=3B output is:<BR>>=3B <BR>>=3B t.rest # NIL? TRUE<=
> >BR>>=3B ISTYPE(t.rest=2CT)? TRUE<BR>>=3B Rest(t.rest) =3D NIL? TRUE<BR>=
> >>=3B conjunction? FALSE<BR>>=3B in ELSE clause...<BR>>=3B <BR>>=3B =
> >TRUE AND TRUE AND TRUE is FALSE??<BR>>=3B <BR>>=3B Note that: <BR>>=
> >=3B <BR>>=3B VAR q=2C w=2C e :=3D TRUE=3B<BR>>=3B <BR>>=3B Debug.Out(=
> >"conjunction? " &=3B Fmt.Bool(<BR>>=3B q AND w AND e))=3B<BR>>=3B <B=
> >R>>=3B results in TRUE (as it should).<BR>>=3B <BR>>=3B <BR>>=3B Mi=
> >ka<BR>>=3B <BR></body>
> ></html>=
> >
> >--_55f6c801-7d57-4602-a131-dda139b64dfd_--
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