Standard strictly above 5.7.2 *and* in 5.6.2 :-)

$ corelist -a if

if was first released with perl 5.006002
  5.006002   0.03      
  5.007003   0.01      
  5.008      0.01      
  5.008001   0.03      
  5.008002   0.03      
  5.008003   0.03      
  5.008004   0.03      
  5.008005   0.03      
  5.008006   0.03      
  5.008007   0.03      
  5.008008   0.05      
  5.009      0.03      
  5.009001   0.0401    
  5.009002   0.0401    
  5.009003   0.05      
  5.009004   0.05      
  5.009005   0.05
[download]

Also note that "if was first released with perl 5.006002" is incorrect - it was first released with perl 5.7.3 in March 2002. 5.6.2 was released in November 2003.