use strict;
use warnings;

use Data::Dumper;

my $str = <<END;
SPECint_base
1
2
3
SPECfp_base
4
5
6
END

open my $fh, '<', \$str or die "Could not open for read:$!\n";

my $SIRtrue;
my $SFRtrue;
my %SIR = ();
my %SFR = ();

while (<$fh>){
    chomp;
    if (/SPECint_base/){
        $SIRtrue = 1;
        $SFRtrue = 0;
        next;
    }
    elsif (/SPECfp_base/){
        $SIRtrue = 0;
        $SFRtrue = 1;
        next;
    }
    if ($SIRtrue)){
        push( @{$SIR{SPECint_base}}, $_ );
    }
    elsif ($SFRtrue){
        push( @{$SFR{SPECfp_base}}, $_ );
    }
}

print Dumper(\%SIR);
print Dumper(\%SFR);