80 bit long doubles. exp(99999) can't.
p4raw-id: //depot/perl@33268
local $!;
# We do want an arithmetic overflow, Inf INF inf Infinity:.
for my $t (
- 'exp(999)',
+ 'exp(99999)', # even 9999 isn't big enough for long doubles
'9**9**9',
'inf',
'Inf',