compile time AUTOLOAD calling (constant folding)

I am thinking of somehow allowing the peephole optimizer or toke.c to 
call AUTOLOAD if AUTOLOAD CV promises to have no side effects from it 
being called at compile time. I found this commit, but it doesn't 
explain anything.

http://perl5.git.perl.org/perl.git/commitdiff/70e590749aafa6e0e67a2220f53f1568bf4e16de

Testing shows no CV and no inlining.

-------------------------------------
#!/usr/bin/perl -w
#use strict;
use B::Concise;
use Devel::Peek 'Dump';
#use Data::Dumper;

#use constant MYCON => 1;
#BEGIN  { eval 'sub MYCON () {1}' }
sub AUTOLOAD {
     eval 'sub MYCON () {1}';
     goto \&MYCON;
}

sub tsub {
     my $s = MYCON();
     print $s."\n";
}
Dump(*MYCON);
tsub();
my $walker = B::Concise::compile('-src','-exec', *tsub{CODE});
$walker->();
Dump(*MYCON);
------------------------------------


------------------------------------
C:\perl521\src>perl n17.pl
SV = PVGV(0xa52fbc) at 0x8fe98c
   REFCNT = 5
   FLAGS = (PADSTALE,MULTI)
   NAME = "MYCON"
   NAMELEN = 5
   GvSTASH = 0x388d5c    "main"
   FLAGS = 0x2
   GP = 0xa7f1e4
     SV = 0x0
     REFCNT = 1
     IO = 0x0
     FORM = 0x0
     AV = 0x0
     HV = 0x0
     CV = 0x0
     CVGEN = 0x0
     GPFLAGS = 0x0 ()
     LINE = 11
     FILE = "n17.pl"
     EGV = 0x8fe98c      "MYCON"
1
B::Concise::compile(CODE(0x98c0cc))
# 15:     my $s = MYCON();
1  <;> nextstate(main 33 n17.pl:15) v
2  <0> pushmark s
3  <#> gv[*MYCON] s/EARLYCV
4  <1> entersub[t2] sKS/TARG
5  <0> padsv[$s:33,34] sRM*/LVINTRO
6  <2> sassign vKS/2
# 16:     print $s."\n";
7  <;> nextstate(main 34 n17.pl:16) v
8  <0> pushmark s
9  <0> padsv[$s:33,34] s
a  <$> const[PV "\n"] s
b  <2> concat[t5] sK/2
c  <@> print sK
d  <1> leavesub[1 ref] K/REFC,1
SV = PVGV(0xa52fbc) at 0x8fe98c
   REFCNT = 5
   FLAGS = (PADSTALE,RMG,MULTI)
   MAGIC = 0x90241c
     MG_VIRTUAL = &PL_vtbl_backref
     MG_TYPE = PERL_MAGIC_backref(<)
     MG_OBJ = 0x8fe66c
   NAME = "MYCON"
   NAMELEN = 5
   GvSTASH = 0x388d5c    "main"
   FLAGS = 0x2
   GP = 0xa7f1e4
     SV = 0x0
     REFCNT = 1
     IO = 0x0
     FORM = 0x0
     AV = 0x0
     HV = 0x0
     CV = 0x8fe66c
     CVGEN = 0x0
     GPFLAGS = 0x0 ()
     LINE = 11
     FILE = "n17.pl"
     EGV = 0x8fe98c      "MYCON"

C:\perl521\src>
------------------------------------

I'm thinking of modifying the gv_fetchsv() at 
http://perl5.git.perl.org/perl.git/blob/01b515d1d793fe9ee31ac67de850d943ce109686:/op.c#l9856 
  to fall back to autoload sub if it exists, and if AUTOLOAD's CV has 
CvCONST flag, since I dont want to add a new flag, AUTOLOAD sub will be 
called at compile time, not runtime from pp_entersub. Any comments?

• compile time AUTOLOAD calling (constant folding) by bulk88
• Re: compile time AUTOLOAD calling (constant folding) by Dave Mitchell
• Re: compile time AUTOLOAD calling (constant folding) by bulk 88
• Re: compile time AUTOLOAD calling (constant folding) by Dave Mitchell