Re^3: Number too big to fit in integer

I get the same with 5.36.0 as I did with 5.26.1. Here's what I originally used to home in on the tipping point:

% /opt/v5.36.0/bin/perl -MMath::BigInt -wle '$z0 = Math::BigInt->new(2
+)**64; for my $i (0..12) { $zi = $z0 + 2**$i; $ni = "$zi"; $d = ($ni 
+== ~0) ? "same" : "differ"; print "$i: $d" }'
0: same
1: same
2: same
3: same
4: same
5: same
6: same
7: same
8: same
9: same
10: same
11: same
12: differ
%
[download]

Using eval "$zi == ~0" to make it more like direct use gives me the same result.

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Re^4: Number too big to fit in integer by syphilis (Archbishop) on Jan 01, 2023 at 02:00 UTC
I get the same with 5.36.0 as I did with 5.26.1. Oh, I see. You were adding powers of 2 to the original value of 2**64. I get the same as you when I run the code you provided. I was incrementing by one: `D:\>perl -MMath::BigInt -wle "$x = Math::BigInt->new(~0); $x++; while( +\"$x\" == ~0){$x++}; print $x;" 18446744073709553665` [download] Of course, this particular perl configuration sees 18446744073709553665 and 18446744073709554600 as the same value, anyway: `D:\>perl -le "print 'ok' if 18446744073709553665 == 184467440737095546 +00;" ok` [download] However, that your 5.26.1 regards 18446744073709554600 and 18446744073709554599 as different values is a bug in 5.26.1. (I see the same bug in my Windows build of 5.26.0.) I believe that perl should regard those two values as equivalent for all IV and NV configurations. `D:\>perl -wle "print 'ok' if 18446744073709554600 == 18446744073709554 +599;" ok` [download] For me, that fails to output 'ok' on 5.26.0. (If 5.26.0 has been built with -Duselongdouble, then 5.26.0 does get it right and outputs 'ok'.) Cheers, Rob	[reply] [d/l] [select]
Re^5: Number too big to fit in integer by hv (Prior) on Jan 01, 2023 at 04:27 UTC
Ok, there has been a change somewhere along the line: if I compare "n more than ~0" against "~0" for integer n, up to 5.28 it first compares different for n = 2985 (ie with 18446744073709554600); with 5.30 and later it first compares different for n = 2050 (ie with 18446744073709553665): `% /opt/v5.28.1/bin/perl -MMath::BigInt -we '$z0 = Math::BigInt->new(~0 +); for (1..4096) { $z1 = $z0 + $_; $n1 = "$z1"; die $_ if $n1 != ~0 } +' 2985 at -e line 1. % /opt/v5.30.0-d/bin/perl -MMath::BigInt -we '$z0 = Math::BigInt->new( +~0); for (1..4096) { $z1 = $z0 + $_; $n1 = "$z1"; die $_ if $n1 != ~0 + }' 2050 at -e line 1. %` [download] (From the naming I know that's a v5.30.0 built with debugging, but that shouldn't make a difference here.)	[reply] [d/l]
Re^6: Number too big to fit in integer by syphilis (Archbishop) on Jan 01, 2023 at 09:40 UTC
Ok, there has been a change somewhere along the line: Yes - beginning with perl-5.30.0, perl uses C's strtod() to assign values, instead of its own (buggy) atof routine that it had previously been using. That fixed many errors in assignment - eg https://github.com/Perl/perl5/issues/8730, which had been reported in Jan 2007. Cheers, Rob	[reply]