xref: /openbsd-src/gnu/usr.bin/perl/t/perf/benchmarks (revision 3d61058aa5c692477b6d18acfbbdb653a9930ff9)

#!perl

# This file specifies an array-of-hashes that define snippets of code that
# can be run by various measurement and profiling tools.
#
# The basic idea is that any time you add an optimisation that is intended
# to make a particular construct faster, then you should add that construct
# to this file.
#
# Under the normal test suite, the test file benchmarks.t does a basic
# compile and run of each of these snippets; not to test performance,
# but just to ensure that the code doesn't have errors.
#
# Over time, it is intended that various measurement and profiling tools
# will be written that can run selected (or all) snippets in various
# environments. These will not be run as part of a normal test suite run.
#
# It is intended that the tests in this file will be lightweight; e.g.
# a hash access, an empty function call, or a single regex match etc.
#
# This file is designed to be read in by 'do' (and in such a way that
# multiple versions of this file from different releases can be read in
# by a single process).
#
# The top-level array has name/hash pairs (we use an array rather than a
# hash so that duplicate keys can be spotted) Each name is a token that
# describes a particular test. Code will be compiled in the package named
# after the token, so it should match /^(\w|::)+$/a. It is intended that
# this can be used on the command line of tools to select particular
# tests.
# In addition, the package names are arranged into an informal hierarchy
# whose top members are (this is subject to change):
#
#     call::     subroutine and method handling
#     expr::     expressions: e.g. $x=1, $foo{bar}[0]
#     func::     perl functions, e.g. func::sort::...
#     loop::     structural code like for, while(), etc
#     regex::    regular expressions
#     string::   string handling
#
#
# Each hash has up to five fields:
#
#   desc  is a description of the test; if not present, it defaults
#           to the same value as the 'code' field
#
#   setup is an optional string containing setup code that is run once
#
#   code  is a string containing the code to run in a loop
#
#   pre   is an optional string containing setup code which is executed
#         just before 'code' for every iteration, but whose execution
#         time is not included in the result
#
#   post  like pre, but executed just after 'code'.
#
# So typically a benchmark tool might execute variations on something like
#
#   eval "package $name; $setup; for (1..1000000) { $pre; $code; $post }"
#
# Currently the only tool that uses this file is Porting/bench.pl;
# try C<perl Porting/bench.pl --help> for more info
#
# ------
#
# Note: for the cachegrind variant, an entry like
#    'foo::bar' => {
#     setup   => 'SETUP',
#     pre     => 'PRE',
#     code    => 'CODE',
#     post    => 'POST',
#   }
# creates two temporary perl sources looking like:
#
#        package foo::bar;
#        BEGIN { srand(0) }
#        SETUP;
#        for my $__loop__ (1..$ARGV[0]) {
#            PRE; 1; POST;
#        }
#
# and as above, but with the loop body replaced with:
#
#            PRE; CODE; POST;
#
# It then pipes each of the two sources into
#
#     PERL_HASH_SEED=0 valgrind [options] someperl [options] - N
#
# where N is set to 10 and then 20.
#
# It then uses the result of those four cachegrind runs to subtract out
# the perl startup and loop overheads (including SETUP, PRE and POST), leaving
# (in theory only CODE);
#
# Note that misleading results may be obtained if each iteration is
# not identical. For example with
#
#     code => '$x .= "foo"',
#
# the string $x gets longer on each iteration. Similarly, a hash might be
# empty on the first iteration, but have entries on subsequent iterations.
#
# To avoid this, use 'pre' or 'post', e.g.
#
#     pre  => '$x  = ""',
#     code => '$x .= "foo"',
#
# Finally, the optional 'compile' key causes the code body to be wrapped
# in eval qw{ sub { ... }}, so that compile time rather than execution
# time is measured.


[
    'call::sub::empty' => {
        desc    => 'function call with no args or body',
        setup   => 'sub f { }',
        code    => 'f()',
    },
    'call::sub::amp_empty' => {
        desc    => '&foo function call with no args or body',
        setup   => 'sub f { }; @_ = ();',
        code    => '&f',
    },
    'call::sub::args3' => {
        desc    => 'function call with 3 local lexical vars',
        setup   => 'sub f { my ($a, $b, $c) = @_; 1 }',
        code    => 'f(1,2,3)',
    },
    'call::sub::args2_ret1' => {
        desc    => 'function call with 2 local lex vars and 1 return value',
        setup   => 'my $x; sub f { my ($a, $b) = @_; $a+$b }',
        code    => '$x = f(1,2)',
    },
    'call::sub::args2_ret1temp' => {
        desc    => 'function call with 2 local lex vars and 1 return TEMP value',
        setup   => 'my $x; sub f { my ($a, $b) = @_; \$a }',
        code    => '$x = f(1,2)',
    },
    'call::sub::args3_ret3' => {
        desc    => 'function call with 3 local lex vars and 3 return values',
        setup   => 'my @a; sub f { my ($a, $b, $c) = @_; $a+$b, $c, 1 }',
        code    => '@a = f(1,2,3)',
    },
    'call::sub::args3_ret3str' => {
        desc    => 'function call with 3 local lex vars and 3 string return values',
        setup   => 'my @a; sub f { my ($a, $b, $c) = @_; my @s = ("aa","bb","cc"); @s }',
        code    => '@a = f(1,2,3)',
    },
    'call::sub::args3_ret3temp' => {
        desc    => 'function call with 3 local lex vars and 3 TEMP return values',
        setup   => 'my @a; sub f { my ($a, $b, $c) = @_; 1..3 }',
        code    => '@a = f(1,2,3)',
    },
    'call::sub::recursive' => {
        desc    => 'basic recursive function call',
        setup   => 'my $x; sub f { my ($i) = @_; $i > 0 ? $i + f($i-1) : 0 }',
        code    => '$x = f(1)',
    },

    'call::sub::scalar' => {
        desc    => 'sub called in scalar context',
        setup   => 'my $x; my @a = 1..4; sub f { @a }',
        code    => '$x = f()',
    },

    'call::goto::empty' => {
        desc    => 'goto &funtion with no args or body',
        setup   => 'sub f { goto &g } sub g {}',
        code    => 'f()',
    },
    'call::goto::args3' => {
        desc    => 'goto &funtion with 3 local lexical vars',
        setup   => 'sub f { goto &g } sub g { my ($a, $b, $c) = @_ }',
        code    => 'f(1,2,3)',
    },


    'expr::array::lex_1const_0' => {
        desc    => 'lexical $array[0]',
        setup   => 'my @a = (1)',
        code    => '$a[0]',
    },
    'expr::array::lex_1const_m1' => {
        desc    => 'lexical $array[-1]',
        setup   => 'my @a = (1)',
        code    => '$a[-1]',
    },
    'expr::array::lex_2const' => {
        desc    => 'lexical $array[const][const]',
        setup   => 'my @a = ([1,2])',
        code    => '$a[0][1]',
    },
    'expr::array::lex_2var' => {
        desc    => 'lexical $array[$i1][$i2]',
        setup   => 'my ($i1,$i2) = (0,1); my @a = ([1,2])',
        code    => '$a[$i1][$i2]',
    },
    'expr::array::ref_lex_2var' => {
        desc    => 'lexical $arrayref->[$i1][$i2]',
        setup   => 'my ($i1,$i2) = (0,1); my $r = [[1,2]]',
        code    => '$r->[$i1][$i2]',
    },
    'expr::array::ref_lex_3const' => {
        desc    => 'lexical $arrayref->[const][const][const]',
        setup   => 'my $r = [[[1,2]]]',
        code    => '$r->[0][0][0]',
    },
    'expr::array::ref_expr_lex_3const' => {
        desc    => '(lexical expr)->[const][const][const]',
        setup   => 'my $r = [[[1,2]]]',
        code    => '($r||0)->[0][0][0]',
    },


    'expr::array::pkg_1const_0' => {
        desc    => 'package $array[0]',
        setup   => '@a = (1)',
        code    => '$a[0]',
    },
    'expr::array::pkg_1const_m1' => {
        desc    => 'package $array[-1]',
        setup   => '@a = (1)',
        code    => '$a[-1]',
    },
    'expr::array::pkg_2const' => {
        desc    => 'package $array[const][const]',
        setup   => '@a = ([1,2])',
        code    => '$a[0][1]',
    },
    'expr::array::pkg_2var' => {
        desc    => 'package $array[$i1][$i2]',
        setup   => '($i1,$i2) = (0,1); @a = ([1,2])',
        code    => '$a[$i1][$i2]',
    },
    'expr::array::ref_pkg_2var' => {
        desc    => 'package $arrayref->[$i1][$i2]',
        setup   => '($i1,$i2) = (0,1); $r = [[1,2]]',
        code    => '$r->[$i1][$i2]',
    },
    'expr::array::ref_pkg_3const' => {
        desc    => 'package $arrayref->[const][const][const]',
        setup   => '$r = [[[1,2]]]',
        code    => '$r->[0][0][0]',
    },
    'expr::array::ref_expr_pkg_3const' => {
        desc    => '(package expr)->[const][const][const]',
        setup   => '$r = [[[1,2]]]',
        code    => '($r||0)->[0][0][0]',
    },

    'expr::array::lex_bool_empty' => {
        desc    => 'empty lexical array in boolean context',
        setup   => 'my @a;',
        code    => '!@a',
    },
    'expr::array::lex_bool_full' => {
        desc    => 'non-empty lexical array in boolean context',
        setup   => 'my @a = 1..10;',
        code    => '!@a',
    },
    'expr::array::lex_scalar_empty' => {
        desc    => 'empty lexical array in scalar context',
        setup   => 'my (@a, $i);',
        code    => '$i = @a',
    },
    'expr::array::lex_scalar_full' => {
        desc    => 'non-empty lexical array in scalar context',
        setup   => 'my @a = 1..10; my $i',
        code    => '$i = @a',
    },
    'expr::array::pkg_bool_empty' => {
        desc    => 'empty lexical array in boolean context',
        setup   => 'our @a;',
        code    => '!@a',
    },
    'expr::array::pkg_bool_full' => {
        desc    => 'non-empty lexical array in boolean context',
        setup   => 'our @a = 1..10;',
        code    => '!@a',
    },
    'expr::array::pkg_scalar_empty' => {
        desc    => 'empty lexical array in scalar context',
        setup   => 'our @a; my $i;',
        code    => '$i = @a',
    },
    'expr::array::pkg_scalar_full' => {
        desc    => 'non-empty lexical array in scalar context',
        setup   => 'our @a = 1..10; my $i',
        code    => '$i = @a',
    },

    'expr::arrayhash::lex_3var' => {
        desc    => 'lexical $h{$k1}[$i]{$k2}',
        setup   => 'my ($i, $k1, $k2) = (0,"foo","bar");'
                    . 'my %h = (foo => [ { bar => 1 } ])',
        code    => '$h{$k1}[$i]{$k2}',
    },
    'expr::arrayhash::pkg_3var' => {
        desc    => 'package $h{$k1}[$i]{$k2}',
        setup   => '($i, $k1, $k2) = (0,"foo","bar");'
                    . '%h = (foo => [ { bar => 1 } ])',
        code    => '$h{$k1}[$i]{$k2}',
    },

    'expr::hash::lex_1const' => {
        desc    => 'lexical $hash{const}',
        setup   => 'my %h = ("foo" => 1)',
        code    => '$h{foo}',
    },
    'expr::hash::lex_2const' => {
        desc    => 'lexical $hash{const}{const}',
        setup   => 'my %h = (foo => { bar => 1 })',
        code    => '$h{foo}{bar}',
    },
    'expr::hash::lex_2var' => {
        desc    => 'lexical $hash{$k1}{$k2}',
        setup   => 'my ($k1,$k2) = qw(foo bar); my %h = ($k1 => { $k2 => 1 })',
        code    => '$h{$k1}{$k2}',
    },
    'expr::hash::ref_lex_2var' => {
        desc    => 'lexical $hashref->{$k1}{$k2}',
        setup   => 'my ($k1,$k2) = qw(foo bar); my $r = {$k1 => { $k2 => 1 }}',
        code    => '$r->{$k1}{$k2}',
    },
    'expr::hash::ref_lex_3const' => {
        desc    => 'lexical $hashref->{const}{const}{const}',
        setup   => 'my $r = {foo => { bar => { baz => 1 }}}',
        code    => '$r->{foo}{bar}{baz}',
    },
    'expr::hash::ref_expr_lex_3const' => {
        desc    => '(lexical expr)->{const}{const}{const}',
        setup   => 'my $r = {foo => { bar => { baz => 1 }}}',
        code    => '($r||0)->{foo}{bar}{baz}',
    },

    'expr::hash::pkg_1const' => {
        desc    => 'package $hash{const}',
        setup   => '%h = ("foo" => 1)',
        code    => '$h{foo}',
    },
    'expr::hash::pkg_2const' => {
        desc    => 'package $hash{const}{const}',
        setup   => '%h = (foo => { bar => 1 })',
        code    => '$h{foo}{bar}',
    },
    'expr::hash::pkg_2var' => {
        desc    => 'package $hash{$k1}{$k2}',
        setup   => '($k1,$k2) = qw(foo bar); %h = ($k1 => { $k2 => 1 })',
        code    => '$h{$k1}{$k2}',
    },
    'expr::hash::ref_pkg_2var' => {
        desc    => 'package $hashref->{$k1}{$k2}',
        setup   => '($k1,$k2) = qw(foo bar); $r = {$k1 => { $k2 => 1 }}',
        code    => '$r->{$k1}{$k2}',
    },
    'expr::hash::ref_pkg_3const' => {
        desc    => 'package $hashref->{const}{const}{const}',
        setup   => '$r = {foo => { bar => { baz => 1 }}}',
        code    => '$r->{foo}{bar}{baz}',
    },
    'expr::hash::ref_expr_pkg_3const' => {
        desc    => '(package expr)->{const}{const}{const}',
        setup   => '$r = {foo => { bar => { baz => 1 }}}',
        code    => '($r||0)->{foo}{bar}{baz}',
    },


    'expr::hash::exists_lex_2var' => {
        desc    => 'lexical exists $hash{$k1}{$k2}',
        setup   => 'my ($k1,$k2) = qw(foo bar); my %h = ($k1 => { $k2 => 1 });',
        code    => 'exists $h{$k1}{$k2}',
    },

    'expr::hash::bool_empty' => {
        desc    => 'empty lexical hash in boolean context',
        setup   => 'my %h;',
        code    => '!%h',
    },
    'expr::hash::bool_empty_unknown' => {
        desc    => 'empty lexical hash in unknown context',
        setup   => 'my ($i, %h); sub f { if (%h) { $i++ }}',
        code    => 'f()',
    },
    'expr::hash::bool_full' => {
        desc    => 'non-empty lexical hash in boolean context',
        setup   => 'my %h = 1..10;',
        code    => '!%h',
    },


    (
        map {
            sprintf('expr::hash::notexists_lex_keylen%04d',$_) => {
                desc    => 'exists on non-key of length '. $_,
                setup   => 'my %h; my $key = "A" x ' . $_ . '; $h{$key."x"} = 1;',
                code    => 'exists $h{$key}',
            },
        } (
            1 .. 24,
            # 1,2,3,7,8,9,14,15,16,20,24,
            50,
            100,
            1000,
        )
    ),
    (
        map {
            sprintf('expr::hash::exists_lex_keylen%04d',$_) => {
                desc    => 'exists on existing key of length '. $_,
                setup   => 'my %h; my $key = "A" x ' . $_ . '; $h{$key} = 1;',
                code    => 'exists $h{$key}',
            },
        } (
            1 .. 24,
            # 1,2,3,7,8,9,14,15,16,20,24,
            50,
            100,
            1000,
        )
    ),

    'expr::hash::delete_lex_2var' => {
        desc    => 'lexical delete $hash{$k1}{$k2}',
        setup   => 'my ($k1,$k2) = qw(foo bar); my %h = ($k1 => { $k2 => 1 });',
        code    => 'delete $h{$k1}{$k2}',
    },


    # list assign, OP_AASSIGN


    # (....) = ()

    'expr::aassign::ma_empty' => {
        desc    => 'my array assigned empty',
        setup   => '',
        code    => 'my @a = ()',
    },
    'expr::aassign::lax_empty' => {
        desc    => 'non-empty lexical array assigned empty',
        setup   => 'my @a = 1..3;',
        code    => '@a = ()',
    },
    'expr::aassign::llax_empty' => {
        desc    => 'non-empty lexical var and array assigned empty',
        setup   => 'my ($x, @a) = 1..4;',
        code    => '($x, @a) = ()',
    },
    'expr::aassign::mh_empty' => {
        desc    => 'my hash assigned empty',
        setup   => '',
        code    => 'my %h = ()',
    },
    'expr::aassign::lhx_empty' => {
        desc    => 'non-empty lexical hash assigned empty',
        setup   => 'my %h = 1..4;',
        code    => '%h = ()',
    },
    'expr::aassign::llhx_empty' => {
        desc    => 'non-empty lexical var and hash assigned empty',
        setup   => 'my ($x, %h) = 1..5;',
        code    => '($x, %h) = ()',
    },
    'expr::aassign::3m_empty' => {
        desc    => 'three my vars assigned empty',
        setup   => '',
        code    => 'my ($x,$y,$z) = ()',
    },
    'expr::aassign::3l_empty' => {
        desc    => 'three lexical vars assigned empty',
        setup   => 'my ($x,$y,$z)',
        code    => '($x,$y,$z) = ()',
    },
    'expr::aassign::3lref_empty' => {
        desc    => 'three lexical ref vars assigned empty',
        setup   => 'my ($x,$y,$z); my $r = []; ',
        code    => '($x,$y,$z) = ($r,$r,$r); ($x,$y,$z) = ()',
    },
    'expr::aassign::pa_empty' => {
        desc    => 'package array assigned empty',
        setup   => '',
        code    => '@a = ()',
    },
    'expr::aassign::pax_empty' => {
        desc    => 'non-empty package array assigned empty',
        setup   => '@a = (1,2,3)',
        code    => '@a = ()',
    },
    'expr::aassign::3p_empty' => {
        desc    => 'three package vars assigned empty',
        setup   => '($x,$y,$z) = 1..3;',
        code    => '($x,$y,$z) = ()',
    },

    # (....) = (1,2,3)

    'expr::aassign::ma_3c' => {
        desc    => 'my array assigned 3 consts',
        setup   => '',
        code    => 'my @a = (1,2,3)',
    },
    'expr::aassign::lax_3c' => {
        desc    => 'non-empty lexical array assigned 3 consts',
        setup   => 'my @a = 1..3;',
        code    => '@a = (1,2,3)',
    },
    'expr::aassign::llax_3c' => {
        desc    => 'non-empty lexical var and array assigned 3 consts',
        setup   => 'my ($x, @a) = 1..4;',
        code    => '($x, @a) = (1,2,3)',
    },
    'expr::aassign::mh_4c' => {
        desc    => 'my hash assigned 4 consts',
        setup   => '',
        code    => 'my %h = qw(a 1 b 2)',
    },
    'expr::aassign::lhx_4c' => {
        desc    => 'non-empty lexical hash assigned 4 consts',
        setup   => 'my %h = qw(a 1 b 2);',
        code    => '%h = qw(c 3 d 4)',
    },
    'expr::aassign::llhx_5c' => {
        desc    => 'non-empty lexical var and array assigned 5 consts',
        setup   => 'my ($x, %h) = (1, qw(a 1 b 2));',
        code    => '($x, %h) = (10, qw(c 3 d 4))',
    },
    'expr::aassign::3m_3c' => {
        desc    => 'three my vars assigned 3 consts',
        setup   => '',
        code    => 'my ($x,$y,$z) = (1,2,3)',
    },
    'expr::aassign::3l_3c' => {
        desc    => 'three lexical vars assigned 3 consts',
        setup   => 'my ($x,$y,$z)',
        code    => '($x,$y,$z) = (1,2,3)',
    },
    'expr::aassign::pa_3c' => {
        desc    => 'package array assigned 3 consts',
        setup   => '',
        code    => '@a = (1,2,3)',
    },
    'expr::aassign::pax_3c' => {
        desc    => 'non-empty package array assigned 3 consts',
        setup   => '@a = (1,2,3)',
        code    => '@a = (1,2,3)',
    },
    'expr::aassign::3p_3c' => {
        desc    => 'three package vars assigned 3 consts',
        setup   => '($x,$y,$z) = 1..3;',
        code    => '($x,$y,$z) = (1,2,3)',
    },

    # (....) = @lexical

    'expr::aassign::ma_la' => {
        desc    => 'my array assigned lexical array',
        setup   => 'my @init = 1..3;',
        code    => 'my @a = @init',
    },
    'expr::aassign::lax_la' => {
        desc    => 'non-empty lexical array assigned lexical array',
        setup   => 'my @init = 1..3; my @a = 1..3;',
        code    => '@a = @init',
    },
    'expr::aassign::llax_la' => {
        desc    => 'non-empty lexical var and array assigned lexical array',
        setup   => 'my @init = 1..3; my ($x, @a) = 1..4;',
        code    => '($x, @a) = @init',
    },
    'expr::aassign::3m_la' => {
        desc    => 'three my vars assigned lexical array',
        setup   => 'my @init = 1..3;',
        code    => 'my ($x,$y,$z) = @init',
    },
    'expr::aassign::3l_la' => {
        desc    => 'three lexical vars assigned lexical array',
        setup   => 'my @init = 1..3; my ($x,$y,$z)',
        code    => '($x,$y,$z) = @init',
    },
    'expr::aassign::pa_la' => {
        desc    => 'package array assigned lexical array',
        setup   => 'my @init = 1..3;',
        code    => '@a = @init',
    },
    'expr::aassign::pax_la' => {
        desc    => 'non-empty package array assigned lexical array',
        setup   => 'my @init = 1..3; @a = @init',
        code    => '@a = @init',
    },
    'expr::aassign::3p_la' => {
        desc    => 'three package vars assigned lexical array',
        setup   => 'my @init = 1..3; ($x,$y,$z) = 1..3;',
        code    => '($x,$y,$z) = @init',
    },

    # (....) = @package

    'expr::aassign::ma_pa' => {
        desc    => 'my array assigned package array',
        setup   => '@init = 1..3;',
        code    => 'my @a = @init',
    },
    'expr::aassign::lax_pa' => {
        desc    => 'non-empty lexical array assigned package array',
        setup   => '@init = 1..3; my @a = 1..3;',
        code    => '@a = @init',
    },
    'expr::aassign::llax_pa' => {
        desc    => 'non-empty lexical var and array assigned package array',
        setup   => '@init = 1..3; my ($x, @a) = 1..4;',
        code    => '($x, @a) = @init',
    },
    'expr::aassign::3m_pa' => {
        desc    => 'three my vars assigned package array',
        setup   => '@init = 1..3;',
        code    => 'my ($x,$y,$z) = @init',
    },
    'expr::aassign::3l_pa' => {
        desc    => 'three lexical vars assigned package array',
        setup   => '@init = 1..3; my ($x,$y,$z)',
        code    => '($x,$y,$z) = @init',
    },
    'expr::aassign::pa_pa' => {
        desc    => 'package array assigned package array',
        setup   => '@init = 1..3;',
        code    => '@a = @init',
    },
    'expr::aassign::pax_pa' => {
        desc    => 'non-empty package array assigned package array',
        setup   => '@init = 1..3; @a = @init',
        code    => '@a = @init',
    },
    'expr::aassign::3p_pa' => {
        desc    => 'three package vars assigned package array',
        setup   => '@init = 1..3; ($x,$y,$z) = 1..3;',
        code    => '($x,$y,$z) = @init',
    },

    # (....) = @_;

    'expr::aassign::ma_defary' => {
        desc    => 'my array assigned @_',
        setup   => '@_ = 1..3;',
        code    => 'my @a = @_',
    },
    'expr::aassign::lax_defary' => {
        desc    => 'non-empty lexical array assigned @_',
        setup   => '@_ = 1..3; my @a = 1..3;',
        code    => '@a = @_',
    },
    'expr::aassign::llax_defary' => {
        desc    => 'non-empty lexical var and array assigned @_',
        setup   => '@_ = 1..3; my ($x, @a) = 1..4;',
        code    => '($x, @a) = @_',
    },
    'expr::aassign::3m_defary' => {
        desc    => 'three my vars assigned @_',
        setup   => '@_ = 1..3;',
        code    => 'my ($x,$y,$z) = @_',
    },
    'expr::aassign::3l_defary' => {
        desc    => 'three lexical vars assigned @_',
        setup   => '@_ = 1..3; my ($x,$y,$z)',
        code    => '($x,$y,$z) = @_',
    },
    'expr::aassign::pa_defary' => {
        desc    => 'package array assigned @_',
        setup   => '@_ = 1..3;',
        code    => '@a = @_',
    },
    'expr::aassign::pax_defary' => {
        desc    => 'non-empty package array assigned @_',
        setup   => '@_ = 1..3; @a = @_',
        code    => '@a = @_',
    },
    'expr::aassign::3p_defary' => {
        desc    => 'three package vars assigned @_',
        setup   => '@_ = 1..3; ($x,$y,$z) = 1..3;',
        code    => '($x,$y,$z) = @_',
    },

    # (....) = %lexical

    'expr::aassign::ma_lh' => {
        desc    => 'my array assigned lexical hash',
        setup   => 'my %h = qw(aardvark 1 banana 2 cucumber 3)',
        code    => 'my @a = %h',
    },


    # (....) = ($lex1,$lex2,$lex3);

    'expr::aassign::ma_3l' => {
        desc    => 'my array assigned lexicals',
        setup   => 'my ($v1,$v2,$v3) = 1..3;',
        code    => 'my @a = ($v1,$v2,$v3)',
    },
    'expr::aassign::lax_3l' => {
        desc    => 'non-empty lexical array assigned lexicals',
        setup   => 'my ($v1,$v2,$v3) = 1..3; my @a = 1..3;',
        code    => '@a = ($v1,$v2,$v3)',
    },
    'expr::aassign::llax_3l' => {
        desc    => 'non-empty lexical var and array assigned lexicals',
        setup   => 'my ($v1,$v2,$v3) = 1..3; my ($x, @a) = 1..4;',
        code    => '($x, @a) = ($v1,$v2,$v3)',
    },
    'expr::aassign::3m_3l' => {
        desc    => 'three my vars assigned lexicals',
        setup   => 'my ($v1,$v2,$v3) = 1..3;',
        code    => 'my ($x,$y,$z) = ($v1,$v2,$v3)',
    },
    'expr::aassign::3l_3l' => {
        desc    => 'three lexical vars assigned lexicals',
        setup   => 'my ($v1,$v2,$v3) = 1..3; my ($x,$y,$z)',
        code    => '($x,$y,$z) = ($v1,$v2,$v3)',
    },
    'expr::aassign::pa_3l' => {
        desc    => 'package array assigned lexicals',
        setup   => 'my ($v1,$v2,$v3) = 1..3;',
        code    => '@a = ($v1,$v2,$v3)',
    },
    'expr::aassign::pax_3l' => {
        desc    => 'non-empty package array assigned lexicals',
        setup   => 'my ($v1,$v2,$v3) = 1..3; @a = @_',
        code    => '@a = ($v1,$v2,$v3)',
    },
    'expr::aassign::3p_3l' => {
        desc    => 'three package vars assigned lexicals',
        setup   => 'my ($v1,$v2,$v3) = 1..3; ($x,$y,$z) = 1..3;',
        code    => '($x,$y,$z) = ($v1,$v2,$v3)',
    },


    # (....) = ($pkg1,$pkg2,$pkg3);

    'expr::aassign::ma_3p' => {
        desc    => 'my array assigned 3 package vars',
        setup   => '($v1,$v2,$v3) = 1..3;',
        code    => 'my @a = ($v1,$v2,$v3)',
    },
    'expr::aassign::lax_3p' => {
        desc    => 'non-empty lexical array assigned 3 package vars',
        setup   => '($v1,$v2,$v3) = 1..3; my @a = 1..3;',
        code    => '@a = ($v1,$v2,$v3)',
    },
    'expr::aassign::llax_3p' => {
        desc    => 'non-empty lexical var and array assigned 3 package vars',
        setup   => '($v1,$v2,$v3) = 1..3; my ($x, @a) = 1..4;',
        code    => '($x, @a) = ($v1,$v2,$v3)',
    },
    'expr::aassign::3m_3p' => {
        desc    => 'three my vars assigned 3 package vars',
        setup   => '($v1,$v2,$v3) = 1..3;',
        code    => 'my ($x,$y,$z) = ($v1,$v2,$v3)',
    },
    'expr::aassign::3l_3p' => {
        desc    => 'three lexical vars assigned 3 package vars',
        setup   => '($v1,$v2,$v3) = 1..3; my ($x,$y,$z)',
        code    => '($x,$y,$z) = ($v1,$v2,$v3)',
    },
    'expr::aassign::pa_3p' => {
        desc    => 'package array assigned 3 package vars',
        setup   => '($v1,$v2,$v3) = 1..3;',
        code    => '@a = ($v1,$v2,$v3)',
    },
    'expr::aassign::pax_3p' => {
        desc    => 'non-empty package array assigned 3 package vars',
        setup   => '($v1,$v2,$v3) = 1..3; @a = @_',
        code    => '@a = ($v1,$v2,$v3)',
    },
    'expr::aassign::3p_3p' => {
        desc    => 'three package vars assigned 3 package vars',
        setup   => '($v1,$v2,$v3) = 1..3; ($x,$y,$z) = 1..3;',
        code    => '($x,$y,$z) = ($v1,$v2,$v3)',
    },


    # (....) = (1,2,$shared);

    'expr::aassign::llax_2c1s' => {
        desc    => 'non-empty lexical var and array assigned 2 consts and 1 shared var',
        setup   => 'my ($x, @a) = 1..4;',
        code    => '($x, @a) = (1,2,$x)',
    },
    'expr::aassign::3l_2c1s' => {
        desc    => 'three lexical vars assigned 2 consts and 1 shared var',
        setup   => 'my ($x,$y,$z) = 1..3;',
        code    => '($x,$y,$z) = (1,2,$x)',
    },
    'expr::aassign::3p_2c1s' => {
        desc    => 'three package vars assigned 2 consts and 1 shared var',
        setup   => '($x,$y,$z) = 1..3;',
        code    => '($x,$y,$z) = (1,2,$x)',
    },


    # ($a,$b) = ($b,$a);

    'expr::aassign::2l_swap' => {
        desc    => 'swap two lexical vars',
        setup   => 'my ($a,$b) = (1,2)',
        code    => '($a,$b) = ($b,$a)',
    },
    'expr::aassign::2p_swap' => {
        desc    => 'swap two package vars',
        setup   => '($a,$b) = (1,2)',
        code    => '($a,$b) = ($b,$a)',
    },
    'expr::aassign::2laelem_swap' => {
        desc    => 'swap two lexical vars',
        setup   => 'my @a = (1,2)',
        code    => '($a[0],$a[1]) = ($a[1],$a[0])',
    },

    # misc list assign

    'expr::aassign::5l_4l1s' => {
        desc    => 'long list of lexical vars, 1 shared',
        setup   => 'my ($a,$b,$c,$d,$e) = 1..5',
        code    => '($a,$b,$c,$d,$e) = ($a,$a,$c,$d,$e)',
    },

    'expr::aassign::5p_4p1s' => {
        desc    => 'long list of package vars, 1 shared',
        setup   => '($a,$b,$c,$d,$e) = 1..5',
        code    => '($a,$b,$c,$d,$e) = ($a,$a,$c,$d,$e)',
    },
    'expr::aassign::5l_defary' => {
        desc    => 'long list of lexical vars to assign @_ to',
        setup   => '@_ = 1..5',
        code    => 'my ($a,$b,$c,$d,$e) = @_',
    },
    'expr::aassign::5l1la_defary' => {
        desc    => 'long list of lexical vars plus long slurp to assign @_ to',
        setup   => '@_ = 1..20',
        code    => 'my ($a,$b,$c,$d,$e,@rest) = @_',
    },
    'expr::aassign::1l_2l' => {
        desc    => 'single lexical LHS',
        setup   => 'my $x = 1;',
        code    => '(undef,$x) = ($x,$x)',
    },
    'expr::aassign::2l_1l' => {
        desc    => 'single lexical RHS',
        setup   => 'my $x = 1;',
        code    => '($x,$x) = ($x)',
    },
    'expr::aassign::2l_1ul' => {
        desc    => 'undef and single lexical RHS',
        setup   => 'my $x = 1;',
        code    => '($x,$x) = (undef, $x)',
    },

    'expr::aassign::2list_lex' => {
        desc    => 'lexical ($x, $y) = (1, 2)',
        setup   => 'my ($x, $y)',
        code    => '($x, $y) = (1, 2)',
    },

    'expr::aassign::lex_rv' => {
        desc    => 'lexical ($ref1, $ref2) = ($ref3, $ref4)',
        setup   => 'my ($r1, $r2, $r3, $r4);
                    ($r1, $r2) = (($r3, $r4) = ([],  []));',
        code    => '($r1, $r2) = ($r3, $r4)',
    },

    'expr::aassign::lex_rv1' => {
        desc    => 'lexical ($ref1, $ref2) = ($ref3, $ref4) where ref1,2 are freed',
        setup   => 'my ($r1, $r2);',
        code    => '($r1, $r2) = ([], []);',
    },

    'expr::aassign::boolean' => {
        desc    => '!(@a = @b)',
        setup   => 'my ($s,@a, @b); @b = (1,2)',
        code    => '!(@a = @b);',
    },
    'expr::aassign::scalar' => {
        desc    => '$scalar = (@a = @b)',
        setup   => 'my ($s, @a, @b); @b = (1,2)',
        code    => '$s = (@a = @b);',
    },

    # array assign of strings

    'expr::aassign::la_3s' => {
        desc    => 'assign 3 strings to empty lexical array',
        setup   => 'my @a',
        code    => '@a = (); @a = qw(abc defg hijkl);',
    },
    'expr::aassign::la_3ts' => {
        desc    => 'assign 3 temp strings to empty lexical array',
        setup   => 'my @a',
        code    => '@a = (); @a = map $_, qw(abc defg hijkl);',
    },
    'expr::aassign::lan_3s' => {
        desc    => 'assign 3 strings to non-empty lexical array',
        setup   => 'my @a = qw(abc defg hijkl)',
        code    => '@a = qw(abc defg hijkl);',
    },
    'expr::aassign::lan_3ts' => {
        desc    => 'assign 3 temp strings to non-empty lexical array',
        setup   => 'my @a = qw(abc defg hijkl)',
        code    => '@a = map $_, qw(abc defg hijkl);',
    },

    # hash assign of strings

    'expr::aassign::lh_2s' => {
        desc    => 'assign 2 strings to empty lexical hash',
        setup   => 'my %h',
        code    => '%h = (); %h = qw(k1 abc k2 defg);',
    },
    'expr::aassign::lh_2ts' => {
        desc    => 'assign 2 temp strings to empty lexical hash',
        setup   => 'my %h',
        code    => '%h = (); %h = map $_, qw(k1 abc k2 defg);',
    },
    'expr::aassign::lhn_2s' => {
        desc    => 'assign 2 strings to non-empty lexical hash',
        setup   => 'my %h = qw(k1 abc k2 defg);',
        code    => '%h = qw(k1 abc k2 defg);',
    },
    'expr::aassign::lhn_2ts' => {
        desc    => 'assign 2 temp strings to non-empty lexical hash',
        setup   => 'my %h = qw(k1 abc k2 defg);',
        code    => '%h = map $_, qw(k1 abc k2 defg);',
    },


    'expr::arith::add_lex_ii' => {
        desc    => 'add two integers and assign to a lexical var',
        setup   => 'my ($x,$y,$z) = 1..3;',
        code    => '$z = $x + $y',
    },
    'expr::arith::add_pkg_ii' => {
        desc    => 'add two integers and assign to a package var',
        setup   => 'my ($x,$y) = 1..2; $z = 3;',
        code    => '$z = $x + $y',
    },
    'expr::arith::add_lex_nn' => {
        desc    => 'add two NVs and assign to a lexical var',
        setup   => 'my ($x,$y,$z) = (1.1, 2.2, 3.3);',
        code    => '$z = $x + $y',
    },
    'expr::arith::add_pkg_nn' => {
        desc    => 'add two NVs and assign to a package var',
        setup   => 'my ($x,$y); ($x,$y,$z) = (1.1, 2.2, 3.3);',
        code    => '$z = $x + $y',
    },
    'expr::arith::add_lex_ni' => {
        desc    => 'add an int and an NV and assign to a lexical var',
        setup   => 'my ($y,$z) = (2.2, 3.3);',
        pre     => 'my $x = 1', # after 1st iter gets upgraded to PVNV
        code    => '$z = $x + $y',
    },
    'expr::arith::add_pkg_ni' => {
        desc    => 'add an int and an NV and assign to a package var',
        setup   => 'my ($y); ($y,$z) = (2.2, 3.3);',
        pre     => 'my $x = 1', # after 1st iter gets upgraded to PVNV
        code    => '$z = $x + $y',
    },
    'expr::arith::add_lex_ss' => {
        desc    => 'add two short strings and assign to a lexical var',
        setup   => 'my ($x,$y,$z) = ("1", "2", 1);',
        code    => '$z = $x + $y; $x = "1"; ',
    },

    'expr::arith::add_lex_ll' => {
        desc    => 'add two long strings and assign to a lexical var',
        setup   => 'my ($x,$y,$z) = ("12345", "23456", 1);',
        code    => '$z = $x + $y; $x = "12345"; ',
    },

    'expr::arith::sub_lex_ii' => {
        desc    => 'subtract two integers and assign to a lexical var',
        setup   => 'my ($x,$y,$z) = 1..3;',
        code    => '$z = $x - $y',
    },
    'expr::arith::sub_pkg_ii' => {
        desc    => 'subtract two integers and assign to a package var',
        setup   => 'my ($x,$y) = 1..2; $z = 3;',
        code    => '$z = $x - $y',
    },
    'expr::arith::sub_lex_nn' => {
        desc    => 'subtract two NVs and assign to a lexical var',
        setup   => 'my ($x,$y,$z) = (1.1, 2.2, 3.3);',
        code    => '$z = $x - $y',
    },
    'expr::arith::sub_pkg_nn' => {
        desc    => 'subtract two NVs and assign to a package var',
        setup   => 'my ($x,$y); ($x,$y,$z) = (1.1, 2.2, 3.3);',
        code    => '$z = $x - $y',
    },
    'expr::arith::sub_lex_ni' => {
        desc    => 'subtract an int and an NV and assign to a lexical var',
        setup   => 'my ($x,$y,$z) = (1, 2.2, 3.3);',
        code    => '$z = $x - $y',
    },
    'expr::arith::sub_pkg_ni' => {
        desc    => 'subtract an int and an NV and assign to a package var',
        setup   => 'my ($x,$y); ($x,$y,$z) = (1, 2.2, 3.3);',
        code    => '$z = $x - $y',
    },

    'expr::arith::mult_lex_ii' => {
        desc    => 'multiply two integers and assign to a lexical var',
        setup   => 'my ($x,$y,$z) = 1..3;',
        code    => '$z = $x * $y',
    },
    'expr::arith::mult_pkg_ii' => {
        desc    => 'multiply two integers and assign to a package var',
        setup   => 'my ($x,$y) = 1..2; $z = 3;',
        code    => '$z = $x * $y',
    },
    'expr::arith::mult_lex_nn' => {
        desc    => 'multiply two NVs and assign to a lexical var',
        setup   => 'my ($x,$y,$z) = (1.1, 2.2, 3.3);',
        code    => '$z = $x * $y',
    },
    'expr::arith::mult_pkg_nn' => {
        desc    => 'multiply two NVs and assign to a package var',
        setup   => 'my ($x,$y); ($x,$y,$z) = (1.1, 2.2, 3.3);',
        code    => '$z = $x * $y',
    },
    'expr::arith::mult_lex_ni' => {
        desc    => 'multiply an int and an NV and assign to a lexical var',
        setup   => 'my ($x,$y,$z) = (1, 2.2, 3.3);',
        code    => '$z = $x * $y',
    },
    'expr::arith::mult_pkg_ni' => {
        desc    => 'multiply an int and an NV and assign to a package var',
        setup   => 'my ($x,$y); ($x,$y,$z) = (1, 2.2, 3.3);',
        code    => '$z = $x * $y',
    },

    # use '!' to test SvTRUE on various classes of value

    'expr::arith::not_PL_undef' => {
        desc    => '!undef (using PL_sv_undef)',
        setup   => 'my $x',
        code    => '$x = !undef',
    },
    'expr::arith::not_PL_no' => {
        desc    => '!($x == $y) (using PL_sv_no)',
        setup   => 'my ($x, $y) = (1,2); my $z;',
        code    => '$z = !($x == $y)',
    },
    'expr::arith::not_PL_zero' => {
        desc    => '!%h (using PL_sv_zero)',
        setup   => 'my ($x, %h)',
        code    => '$x = !%h',
    },
    'expr::arith::not_PL_yes' => {
        desc    => '!($x == $y) (using PL_sv_yes)',
        setup   => 'my ($x, $y) = (1,1); my $z;',
        code    => '$z = !($x == $y)',
    },
    'expr::arith::not_undef' => {
        desc    => '!$y where $y is undef',
        setup   => 'my ($x, $y)',
        code    => '$x = !$y',
    },
    'expr::arith::not_0' => {
        desc    => '!$x where $x is 0',
        setup   => 'my ($x, $y) = (0, 0)',
        code    => '$y = !$x',
    },
    'expr::arith::not_1' => {
        desc    => '!$x where $x is 1',
        setup   => 'my ($x, $y) = (1, 0)',
        code    => '$y = !$x',
    },
    'expr::arith::not_string' => {
        desc    => '!$x where $x is "foo"',
        setup   => 'my ($x, $y) = ("foo", 0)',
        code    => '$y = !$x',
    },
    'expr::arith::not_ref' => {
        desc    => '!$x where $s is an array ref',
        setup   => 'my ($x, $y) = ([], 0)',
        code    => '$y = !$x',
    },

    'expr::arith::preinc' => {
        setup   => 'my $x = 1;',
        code    => '++$x',
    },
    'expr::arith::predec' => {
        setup   => 'my $x = 1;',
        code    => '--$x',
    },
    'expr::arith::postinc' => {
        desc    => '$x++',
        setup   => 'my $x = 1; my $y',
        code    => '$y = $x++', # scalar context so not optimised to ++$x
    },
    'expr::arith::postdec' => {
        desc    => '$x--',
        setup   => 'my $x = 1; my $y',
        code    => '$y = $x--', # scalar context so not optimised to --$x
    },


    # concatenation; quite possibly optimised to OP_MULTICONCAT

    'expr::concat::cl' => {
        setup   => 'my $lex = "abcd"',
        code    => '"foo" . $lex',
    },
    'expr::concat::lc' => {
        setup   => 'my $lex = "abcd"',
        code    => '$lex . "foo"',
    },
    'expr::concat::ll' => {
        setup   => 'my $lex1 = "abcd";  my $lex2 = "wxyz"',
        code    => '$lex1 . $lex2',
    },

    'expr::concat::l_append_c' => {
        setup   => 'my $lex',
        pre     => '$lex = "abcd"',
        code    => '$lex .= "foo"',
    },
    'expr::concat::l_append_l' => {
        setup   => 'my $lex1;  my $lex2 = "wxyz"',
        pre     => '$lex1 = "abcd"',
        code    => '$lex1 .= $lex2',
    },
    'expr::concat::l_append_ll' => {
        setup   => 'my $lex1; my $lex2 = "pqrs"; my $lex3 = "wxyz"',
        pre     => '$lex1 = "abcd"',
        code    => '$lex1 .= $lex2 . $lex3',
    },
    'expr::concat::l_append_clclc' => {
        setup   => 'my $lex1; my $lex2 = "pqrs"; my $lex3 = "wxyz"',
        pre     => '$lex1 = "abcd"',
        code    => '$lex1 .= "-foo-$lex2-foo-$lex3-foo"',
    },
    'expr::concat::l_append_lll' => {
        setup   => 'my $lex1; my ($lex2, $lex3, $lex4) = qw(pqrs wxyz 1234)',
        pre     => '$lex1 = "abcd"',
        code    => '$lex1 .= $lex2 . $lex3 . $lex4',
    },

    'expr::concat::m_ll' => {
        setup   => 'my $lex1 = "abcd";  my $lex2 = "wxyz"',
        code    => 'my $lex = $lex1 . $lex2',
    },
    'expr::concat::m_lll' => {
        setup   => 'my $lex1 = "abcd"; my $lex2 = "pqrs"; my $lex3 = "wxyz"',
        code    => 'my $lex = $lex1 . $lex2 . $lex3',
    },
    'expr::concat::m_cl' => {
        setup   => 'my $lex1 = "abcd"',
        code    => 'my $lex = "const$lex1"',
    },
    'expr::concat::m_clclc' => {
        setup   => 'my $lex1 = "abcd"; my $lex2 = "wxyz"',
        code    => 'my $lex = "foo=$lex1 bar=$lex2\n"',
    },
    'expr::concat::m_clclc_long' => {
        desc    => 'my $lex = "foooooooooo=$lex1 baaaaaaaaar=$lex2\n" where lex1/2 are 400 chars',
        setup   => 'my $lex1 = "abcd" x 100; my $lex2 = "wxyz" x 100',
        code    => 'my $lex = "foooooooooo=$lex1 baaaaaaaaar=$lex2\n"',
    },

    'expr::concat::l_ll' => {
        setup   => 'my $lex; my $lex1 = "abcd";  my $lex2 = "wxyz"',
        code    => '$lex = $lex1 . $lex2',
    },
    'expr::concat::l_ll_ldup' => {
        setup   => 'my $lex1; my $lex2 = "wxyz"',
        pre     => '$lex1 = "abcd"',
        code    => '$lex1 = $lex1 . $lex2',
    },
    'expr::concat::l_ll_rdup' => {
        setup   => 'my $lex1; my $lex2 = "wxyz"',
        pre     => '$lex1 = "abcd"',
        code    => '$lex1 = $lex2 . $lex1',
    },
    'expr::concat::l_ll_lrdup' => {
        setup   => 'my $lex1',
        pre     => '$lex1 = "abcd"',
        code    => '$lex1 = $lex1 . $lex1',
    },
    'expr::concat::l_lll' => {
        setup   => 'my $lex; my $lex1 = "abcd"; my $lex2 = "pqrs"; my $lex3 = "wxyz"',
        code    => '$lex = $lex1 . $lex2 . $lex3',
    },
    'expr::concat::l_lllll' => {
        setup   => 'my $lex; my $lex1 = "abcd"; my $lex2 = "pqrs"; my $lex3 = "wxyz"; my $lex4 = "the quick brown fox"; my $lex5 = "to be, or not to be..."',
        code    => '$lex = $lex1 . $lex2 . $lex3 . $lex4 . $lex5',
    },
    'expr::concat::l_cl' => {
        setup   => 'my $lex; my $lex1 = "abcd"',
        code    => '$lex = "const$lex1"',
    },
    'expr::concat::l_clclc' => {
        setup   => 'my $lex; my $lex1 = "abcd"; my $lex2 = "wxyz"',
        code    => '$lex = "foo=$lex1 bar=$lex2\n"',
    },
    'expr::concat::l_clclc_long' => {
        desc    => '$lex = "foooooooooo=$lex1 baaaaaaaaar=$lex2\n" where lex1/2 are 400 chars',
        setup   => 'my $lex; my $lex1 = "abcd" x 100; my $lex2 = "wxyz" x 100',
        code    => '$lex = "foooooooooo=$lex1 baaaaaaaaar=$lex2\n"',
    },
    'expr::concat::l_clclclclclc' => {
        setup   => 'my $lex; my $lex1 = "abcd"; my $lex2 = "pqrs"; my $lex3 = "the quick brown fox"; my $lex4 = "to be, or not to be..."',
        code    => '$lex = "foo1=$lex1 foo2=$lex2 foo3=$lex3 foo4=$lex4\n"',
    },

    'expr::concat::g_append_c' => {
        setup   => 'our $pkg',
        pre     => '$pkg = "abcd"',
        code    => '$pkg .= "foo"',
    },
    'expr::concat::g_append_l' => {
        setup   => 'our $pkg;  my $lex1 = "wxyz"',
        pre     => '$pkg = "abcd"',
        code    => '$pkg .= $lex1',
    },
    'expr::concat::g_append_ll' => {
        setup   => 'our $pkg; my $lex1 = "pqrs"; my $lex2 = "wxyz"',
        pre     => '$pkg = "abcd"',
        code    => '$pkg .= $lex1 . $lex2',
    },
    'expr::concat::g_append_clclc' => {
        setup   => 'our $pkg; my $lex1 = "pqrs"; my $lex2 = "wxyz"',
        pre     => '$pkg = "abcd"',
        code    => '$pkg .= "-foo-$lex1-foo-$lex2-foo-"',
    },

    'expr::concat::g_ll' => {
        setup   => 'our $pkg; my $lex1 = "abcd";  my $lex2 = "wxyz"',
        code    => '$pkg = $lex1 . $lex2',
    },
    'expr::concat::g_gl_ldup' => {
        setup   => 'our $pkg;  my $lex2 = "wxyz"',
        pre     => '$pkg = "abcd"',
        code    => '$pkg = $pkg . $lex2',
    },
    'expr::concat::g_lg_rdup' => {
        setup   => 'our $pkg;  my $lex1 = "wxyz"',
        pre     => '$pkg = "abcd"',
        code    => '$pkg = $lex1 . $pkg',
    },
    'expr::concat::g_gg_lrdup' => {
        setup   => 'our $pkg',
        pre     => '$pkg = "abcd"',
        code    => '$pkg = $pkg . $pkg',
    },
    'expr::concat::g_lll' => {
        setup   => 'our $pkg; my $lex1 = "abcd"; my $lex2 = "pqrs"; my $lex3 = "wxyz"',
        code    => '$pkg = $lex1 . $lex2 . $lex3',
    },
    'expr::concat::g_cl' => {
        setup   => 'our $pkg; my $lex1 = "abcd"',
        code    => '$pkg = "const$lex1"',
    },
    'expr::concat::g_clclc' => {
        setup   => 'our $pkg; my $lex1 = "abcd"; my $lex2 = "wxyz"',
        code    => '$pkg = "foo=$lex1 bar=$lex2\n"',
    },
    'expr::concat::g_clclc_long' => {
        desc    => '$pkg = "foooooooooo=$lex1 baaaaaaaaar=$lex2\n" where lex1/2 are 400 chars',
        setup   => 'our $pkg; my $lex1 = "abcd" x 100; my $lex2 = "wxyz" x 100',
        code    => '$pkg = "foooooooooo=$lex1 baaaaaaaaar=$lex2\n"',
    },

    'expr::concat::utf8_uuu' => {
        desc    => 'my $s = $a.$b.$c where all args are utf8',
        setup   => 'my $s; my $a = "ab\x{100}cde"; my $b = "\x{101}fghij"; my $c = "\x{102}klmn"',
        code    => '$s = $a.$b.$c',
    },
    'expr::concat::utf8_suu' => {
        desc    => 'my $s = "foo=$a bar=$b baz=$c" where $b,$c are utf8',
        setup   => 'my $s; my $a = "abcde"; my $b = "\x{100}fghij"; my $c = "\x{101}klmn"',
        code    => '$s = "foo=$a bar=$b baz=$c"',
    },
    'expr::concat::utf8_usu' => {
        desc    => 'my $s = "foo=$a bar=$b baz=$c" where $a,$c are utf8',
        setup   => 'my $s; my $a = "ab\x{100}cde"; my $b = "fghij"; my $c = "\x{101}klmn"',
        code    => '$s = "foo=$a bar=$b baz=$c"',
    },
    'expr::concat::utf8_usx' => {
        desc    => 'my $s = "foo=$a bar=$b baz=$c" where $a is utf8, $c has 0x80',
        setup   => 'my $s; my $a = "ab\x{100}cde"; my $b = "fghij"; my $c = "\x80\x81klmn"',
        code    => '$s = "foo=$a bar=$b baz=$c"',
    },

    'expr::concat::utf8_s_append_uuu' => {
        desc    => '$s .= $a.$b.$c where all RH args are utf8',
        setup   => 'my $s; my $a = "ab\x{100}cde"; my $b = "\x{101}fghij"; my $c = "\x{102}klmn"',
        pre     => '$s = "abcd"',
        code    => '$s .= $a.$b.$c',
    },
    'expr::concat::utf8_s_append_suu' => {
        desc    => '$s .= "foo=$a bar=$b baz=$c" where $b,$c are utf8',
        setup   => 'my $s; my $a = "abcde"; my $b = "\x{100}fghij"; my $c = "\x{101}klmn"',
        pre     => '$s = "abcd"',
        code    => '$s .= "foo=$a bar=$b baz=$c"',
    },
    'expr::concat::utf8_s_append_usu' => {
        desc    => '$s .= "foo=$a bar=$b baz=$c" where $a,$c are utf8',
        setup   => 'my $s; my $a = "ab\x{100}cde"; my $b = "fghij"; my $c = "\x{101}klmn"',
        pre     => '$s = "abcd"',
        code    => '$s .= "foo=$a bar=$b baz=$c"',
    },
    'expr::concat::utf8_s_append_usx' => {
        desc    => '$s .= "foo=$a bar=$b baz=$c" where $a is utf8, $c has 0x80',
        setup   => 'my $s; my $a = "ab\x{100}cde"; my $b = "fghij"; my $c = "\x80\x81klmn"',
        pre     => '$s = "abcd"',
        code    => '$s .= "foo=$a bar=$b baz=$c"',
    },

    'expr::concat::utf8_u_append_uuu' => {
        desc    => '$s .= $a.$b.$c where all args are utf8',
        setup   => 'my $s; my $a = "ab\x{100}cde"; my $b = "\x{101}fghij"; my $c = "\x{102}klmn"',
        pre     => '$s = "\x{100}wxyz"',
        code    => '$s .= $a.$b.$c',
    },
    'expr::concat::utf8_u_append_suu' => {
        desc    => '$s .= "foo=$a bar=$b baz=$c" where $s,$b,$c are utf8',
        setup   => 'my $s; my $a = "abcde"; my $b = "\x{100}fghij"; my $c = "\x{101}klmn"',
        pre     => '$s = "\x{100}wxyz"',
        code    => '$s .= "foo=$a bar=$b baz=$c"',
    },
    'expr::concat::utf8_u_append_usu' => {
        desc    => '$s .= "foo=$a bar=$b baz=$c" where $s,$a,$c are utf8',
        setup   => 'my $s; my $a = "ab\x{100}cde"; my $b = "fghij"; my $c = "\x{101}klmn"',
        pre     => '$s = "\x{100}wxyz"',
        code    => '$s .= "foo=$a bar=$b baz=$c"',
    },
    'expr::concat::utf8_u_append_usx' => {
        desc    => '$s .= "foo=$a bar=$b baz=$c" where $s,$a are utf8, $c has 0x80',
        setup   => 'my $s; my $a = "ab\x{100}cde"; my $b = "fghij"; my $c = "\x80\x81klmn"',
        pre     => '$s = "\x{100}wxyz"',
        code    => '$s .= "foo=$a bar=$b baz=$c"',
    },

    'expr::concat::nested_mutator' => {
        setup   => 'my $lex1; my ($lex2, $lex3, $lex4) = qw(abcd pqrs wxyz)',
        pre     => '$lex1 = "QPR"',
        code    => '(($lex1 .= $lex2) .= $lex3) .= $lex4',
    },


    # concatenation with magic vars;
    # quite possibly optimised to OP_MULTICONCAT

    'expr::concat::mg::cM' => {
        setup   => '"abcd" =~ /(.*)/',
        code    => '"foo" . $1',
    },
    'expr::concat::mg::Mc' => {
        setup   => '"abcd" =~ /(.*)/',
        code    => '$1 . "foo"',
    },
    'expr::concat::mg::MM' => {
        setup   => '"abcd" =~ /(.*)/',
        code    => '$1 . $1',
    },

    'expr::concat::mg::l_append_M' => {
        setup   => 'my $lex; "abcd" =~ /(.*)/;',
        pre     => '$lex = "abcd"',
        code    => '$lex .= $1',
    },
    'expr::concat::mg::l_append_MM' => {
        setup   => 'my $lex; "abcd" =~ /(.*)/;',
        pre     => '$lex = "abcd"',
        code    => '$lex .= $1 .$1',
    },
    'expr::concat::mg::l_append_cMcMc' => {
        setup   => 'my $lex; "abcd" =~ /(.*)/;',
        pre     => '$lex = "abcd"',
        code    => '$lex .= "-foo-$1-foo-$1-foo"',
    },
    'expr::concat::mg::l_append_MMM' => {
        setup   => 'my $lex; "abcd" =~ /(.*)/;',
        pre     => '$lex = "abcd"',
        code    => '$lex .= $1 .$1 . $1',
    },

    'expr::concat::mg::m_MM' => {
        setup   => '"abcd" =~ /(.*)/;',
        code    => 'my $lex = $1 . $1',
    },
    'expr::concat::mg::m_MMM' => {
        setup   => '"abcd" =~ /(.*)/;',
        code    => 'my $lex = $1 . $1 . $1',
    },
    'expr::concat::mg::m_cL' => {
        setup   => '"abcd" =~ /(.*)/;',
        code    => 'my $lex = "const$1"',
    },
    'expr::concat::mg::m_cMcMc' => {
        setup   => '"abcd" =~ /(.*)/;',
        code    => 'my $lex = "foo=$1 bar=$1\n"',
    },
    'expr::concat::mg::m_cMcMc_long' => {
        desc    => 'my $lex = "foooooooooo=$1 baaaaaaaaar=$1\n" where $1 is 400 chars',
        setup   => 'my $s = "abcd" x 100; $s =~ /(.*)/;',
        code    => 'my $lex = "foooooooooo=$1 baaaaaaaaar=$1\n"',
    },

    'expr::concat::mg::l_MM' => {
        setup   => 'my $lex; "abcd" =~ /(.*)/;',
        code    => '$lex = $1 . $1',
    },
    'expr::concat::mg::l_lM_ldup' => {
        setup   => 'my $lex1; "abcd" =~ /(.*)/;',
        pre     => '$lex1 = "abcd"',
        code    => '$lex1 = $lex1 . $1',
    },
    'expr::concat::mg::l_Ml_rdup' => {
        setup   => 'my $lex1; "abcd" =~ /(.*)/;',
        pre     => '$lex1 = "abcd"',
        code    => '$lex1 = $1 . $lex1',
    },
    'expr::concat::mg::l_MMM' => {
        setup   => 'my $lex; "abcd" =~ /(.*)/;',
        code    => '$lex = $1 . $1 . $1',
    },
    'expr::concat::mg::l_MMMMM' => {
        setup   => 'my $lex; "abcd" =~ /(.*)/;',
        code    => '$lex = $1 . $1 . $1 . $1 . $1',
    },
    'expr::concat::mg::l_cM' => {
        setup   => 'my $lex; "abcd" =~ /(.*)/;',
        code    => '$lex = "const$1"',
    },
    'expr::concat::mg::l_cMcMc' => {
        setup   => 'my $lex; "abcd" =~ /(.*)/;',
        code    => '$lex = "foo=$1 bar=$1\n"',
    },
    'expr::concat::mg::l_cMcMc_long' => {
        desc    => '$lex = "foooooooooo=$1 baaaaaaaaar=$1\n" where $1 is 400 chars',
        setup   => 'my $s = "abcd" x 100; $s =~ /(.*)/;',
        code    => '$lex = "foooooooooo=$1 baaaaaaaaar=$1\n"',
    },
    'expr::concat::mg::l_cMcMcMcMcMc' => {
        setup   => 'my $lex; "abcd" =~ /(.*)/;',
        code    => '$lex = "foo1=$1 foo2=$1 foo3=$1 foo4=$1\n"',
    },

    'expr::concat::mg::g_append_M' => {
        setup   => 'our $pkg; "abcd" =~ /(.*)/;',
        pre     => '$pkg = "abcd"',
        code    => '$pkg .= $1',
    },
    'expr::concat::mg::g_append_MM' => {
        setup   => 'our $pkg; "abcd" =~ /(.*)/;',
        pre     => '$pkg = "abcd"',
        code    => '$pkg .= $1',
        code    => '$pkg .= $1 . $1',
    },
    'expr::concat::mg::g_append_cMcMc' => {
        setup   => 'our $pkg; "abcd" =~ /(.*)/;',
        pre     => '$pkg = "abcd"',
        code    => '$pkg .= "-foo-$1-foo-$1-foo-"',
    },

    'expr::concat::mg::g_MM' => {
        setup   => 'our $pkg; "abcd" =~ /(.*)/;',
        code    => '$pkg = $1 . $1',
    },
    'expr::concat::mg::g_gM_ldup' => {
        setup   => 'our $pkg; "abcd" =~ /(.*)/;',
        pre     => '$pkg = "abcd"',
        code    => '$pkg = $pkg . $1',
    },
    'expr::concat::mg::g_Mg_rdup' => {
        setup   => 'our $pkg; "abcd" =~ /(.*)/;',
        pre     => '$pkg = "abcd"',
        code    => '$pkg = $1 . $pkg',
    },
    'expr::concat::mg::g_MMM' => {
        setup   => 'our $pkg; "abcd" =~ /(.*)/;',
        code    => '$pkg = $1 . $1 . $1',
    },
    'expr::concat::mg::g_cM' => {
        setup   => 'our $pkg; "abcd" =~ /(.*)/;',
        code    => '$pkg = "const$1"',
    },
    'expr::concat::mg::g_cMcMc' => {
        setup   => 'our $pkg; "abcd" =~ /(.*)/;',
        code    => '$pkg = "foo=$1 bar=$1\n"',
    },
    'expr::concat::mg::g_cMcMc_long' => {
        desc    => '$lex = "foooooooooo=$1 baaaaaaaaar=$1\n" where $1 is 400 chars',
        setup   => 'our $pkg; my $s = "abcd" x 100; $s =~ /(.*)/;',
        code    => '$pkg = "foooooooooo=$1 baaaaaaaaar=$1\n"',
    },

    'expr::concat::mg::utf8_uuu' => {
        desc    => 'my $s = $1.$1.$1 where $1 utf8',
        setup   => 'my $s; "ab\x{100}cde" =~ /(.*)/;',
        code    => '$s = $1.$1.$1',
    },
    'expr::concat::mg::utf8_suu' => {
        desc    => 'my $s = "foo=$a bar=$1 baz=$1" where $1 is utf8',
        setup   => 'my $s; my $a = "abcde"; "ab\x{100}cde" =~ /(.*)/;',
        code    => '$s = "foo=$a bar=$1 baz=$1"',
    },

    # OP_MULTICONCAT with magic within s///g - see GH #21360

    'expr::concat::mg::subst1_1' => {
        desc    => 's/(.)/$1-/g, 1 iteration',
        pre     => '$_  = "a"',
        code    => 's/(.)/$1-/g',
    },

    'expr::concat::mg::subst1_2' => {
        desc    => 's/(.)/$1-/g, 2 iterations',
        pre     => '$_  = "aa"',
        code    => 's/(.)/$1-/g',
    },

    'expr::concat::mg::subst1_5' => {
        desc    => 's/(.)/$1-/g, 5 iterations',
        pre     => '$_  = "aaaaa"',
        code    => 's/(.)/$1-/g',
    },

    'expr::concat::mg::subst2_1' => {
        desc    => 's/(.)/$1-$1/g, 1 iteration',
        pre     => '$_  = "a"',
        code    => 's/(.)/$1-/g',
    },

    'expr::concat::mg::subst3_1' => {
        desc    => 's/(.)/$1-$1-$1/g, 1 iteration',
        pre     => '$_  = "a"',
        code    => 's/(.)/$1-$1-$1/g',
    },



    # scalar assign, OP_SASSIGN

    'expr::sassign::undef_lex' => {
        setup   => 'my $x',
        code    => '$x = undef',
    },
    'expr::sassign::undef_lex_direc' => {
        setup   => 'my $x',
        code    => 'undef $x',
    },
    'expr::sassign::undef_my_lex' => {
        setup   => '',
        code    => 'my $x = undef',
    },
    'expr::sassign::undef_my_lex_direc' => {
        setup   => '',
        code    => 'undef my $x',
    },

    'expr::sassign::anonlist' => {
        setup   => '',
        code => '$x = []'
    },
    'expr::sassign::anonlist_lex' => {
        setup   => 'my $x',
        code => '$x = []'
    },
    'expr::sassign::my_anonlist_lex' => {
        setup   => '',
        code => 'my $x = []'
    },
    'expr::sassign::anonhash' => {
        setup   => '',
        code => '$x = {}'
    },
    'expr::sassign::anonhash_lex' => {
        setup   => 'my $x',
        code => '$x = {}'
    },
    'expr::sassign::my_anonhash_lex' => {
        setup   => '',
        code => 'my $x = {}'
    },

    'expr::sassign::my_conststr' => {
        setup   => '',
        code    => 'my $x = "abc"',
    },
    'expr::sassign::scalar_lex_int' => {
        desc    => 'lexical $x = 1',
        setup   => 'my $x',
        code    => '$x = 1',
    },
    'expr::sassign::scalar_lex_str' => {
        desc    => 'lexical $x = "abc"',
        setup   => 'my $x',
        code    => '$x = "abc"',
    },
    'expr::sassign::scalar_lex_strint' => {
        desc    => 'lexical $x = 1 where $x was previously a string',
        setup   => 'my $x = "abc"',
        code    => '$x = 1',
    },
    'expr::sassign::scalar_lex_intstr' => {
        desc    => 'lexical $x = "abc" where $x was previously an int',
        setup   => 'my $x = 1;',
        code    => '$x = "abc"',
    },
    'expr::sassign::lex_rv' => {
        desc    => 'lexical $ref1 = $ref2;',
        setup   => 'my $r1 = []; my $r = $r1;',
        code    => '$r = $r1;',
    },
    'expr::sassign::lex_rv1' => {
        desc    => 'lexical $ref1 = $ref2; where $$ref1 gets freed',
        setup   => 'my $r1 = []; my $r',
        code    => '$r = []; $r = $r1;',
    },

    'expr::sassign::aelemfast_lex_assign' => {
        desc    => 'lexical $x[0] = 1',
        setup   => 'my @x',
        code    => '$x[0] = 1',
    },
    'expr::sassign::aelemfast_lex_assign_ref' => {
        desc    => 'lexical $x[0] = []',
        setup   => 'my @x',
        code    => '$x[0] = []',
    },
    'expr::sassign::aelemfast_lex_assign_deref' => {
        desc    => 'lexical $x[0][1]',
        setup   => 'my @x = ([1,2])',
        code    => '$x[0][1] = 1',
    },

    'expr::sassign::bless_lex' => {
        setup   => 'my $x',
        code    => '$x = bless {}, "X"'
    },

    'func::grep::bool0' => {
        desc    => 'grep returning 0 items in boolean context',
        setup   => 'my @a;',
        code    => '!grep $_, @a;',
    },
    'func::grep::bool1' => {
        desc    => 'grep returning 1 item in boolean context',
        setup   => 'my @a =(1);',
        code    => '!grep $_, @a;',
    },
    'func::grep::scalar0' => {
        desc    => 'returning 0 items in scalar context',
        setup   => 'my $g; my @a;',
        code    => '$g = grep $_, @a;',
    },
    'func::grep::scalar1' => {
        desc    => 'returning 1 item in scalar context',
        setup   => 'my $g; my @a =(1);',
        code    => '$g = grep $_, @a;',
    },

    # (index() == -1) and variants optimise away the op_const and op_eq
    # and any assignment to a lexical var
    'func::index::bool' => {
        desc    => '(index() == -1) for match',
        setup   => 'my $x = "aaaab"',
        code    => 'index($x, "b") == -1',
    },
    'func::index::bool_fail' => {
        desc    => '(index() == -1) for no match',
        setup   => 'my $x = "aaaab"',
        code    => 'index($x, "c") == -1',
    },
    'func::index::lex_bool' => {
        desc    => '$lex = (index() == -1) for match',
        setup   => 'my $r; my $x = "aaaab"',
        code    => '$r = index($x, "b") == -1',
    },
    'func::index::lex_bool_fail' => {
        desc    => '$lex = (index() == -1) for no match',
        setup   => 'my $r; my $x = "aaaab"',
        code    => '$r = index($x, "c") == -1',
    },

    # using a const string as second arg to index triggers using FBM.
    # the FBM matcher special-cases 1,2-byte strings.
    #
    'func::index::short_const1' => {
        desc    => 'index of a short string against a 1 char const substr',
        setup   => 'my $x = "aaaab"',
        code    => 'index $x, "b"',
    },
    'func::index::long_const1' => {
        desc    => 'index of a long string against a 1 char const substr',
        setup   => 'my $x = "a" x 1000 . "b"',
        code    => 'index $x, "b"',
    },
    'func::index::short_const2aabc_bc' => {
        desc    => 'index of a short string against a 2 char const substr',
        setup   => 'my $x = "aaaabc"',
        code    => 'index $x, "bc"',
    },
    'func::index::long_const2aabc_bc' => {
        desc    => 'index of a long string against a 2 char const substr',
        setup   => 'my $x = "a" x 1000 . "bc"',
        code    => 'index $x, "bc"',
    },
    'func::index::long_const2aa_ab' => {
        desc    => 'index of a long string aaa.. against const substr "ab"',
        setup   => 'my $x = "a" x 1000',
        code    => 'index $x, "ab"',
    },
    'func::index::long_const2bb_ab' => {
        desc    => 'index of a long string bbb.. against const substr "ab"',
        setup   => 'my $x = "b" x 1000',
        code    => 'index $x, "ab"',
    },
    'func::index::long_const2aa_bb' => {
        desc    => 'index of a long string aaa.. against const substr "bb"',
        setup   => 'my $x = "a" x 1000',
        code    => 'index $x, "bb"',
    },
    # this one is designed to be pathological
    'func::index::long_const2ab_aa' => {
        desc    => 'index of a long string abab.. against const substr "aa"',
        setup   => 'my $x = "ab" x 500',
        code    => 'index $x, "aa"',
    },
    # near misses with gaps, 1st letter
    'func::index::long_const2aaxx_xy' => {
        desc    => 'index of a long string with "xx"s against const substr "xy"',
        setup   => 'my $x = "aaaaaaaaxx" x 100',
        code    => 'index $x, "xy"',
    },
    # near misses with gaps, 2nd letter
    'func::index::long_const2aayy_xy' => {
        desc    => 'index of a long string with "yy"s against const substr "xy"',
        setup   => 'my $x = "aaaaaaaayy" x 100',
        code    => 'index $x, "xy"',
    },
    # near misses with gaps, duplicate letter
    'func::index::long_const2aaxy_xx' => {
        desc    => 'index of a long string with "xy"s against const substr "xx"',
        setup   => 'my $x = "aaaaaaaaxy" x 100',
        code    => 'index $x, "xx"',
    },
    # alternating near misses with gaps
    'func::index::long_const2aaxxaayy_xy' => {
        desc    => 'index of a long string with "xx/yy"s against const substr "xy"',
        setup   => 'my $x = "aaaaaaaaxxbbbbbbbbyy" x 50',
        code    => 'index $x, "xy"',
    },
    'func::index::short_const3aabcd_bcd' => {
        desc    => 'index of a short string against a 3 char const substr',
        setup   => 'my $x = "aaaabcd"',
        code    => 'index $x, "bcd"',
    },
    'func::index::long_const3aabcd_bcd' => {
        desc    => 'index of a long string against a 3 char const substr',
        setup   => 'my $x = "a" x 1000 . "bcd"',
        code    => 'index $x, "bcd"',
    },
    'func::index::long_const3ab_abc' => {
        desc    => 'index of a long string of "ab"s against a 3 char const substr "abc"',
        setup   => 'my $x = "ab" x 500',
        code    => 'index $x, "abc"',
    },
    'func::index::long_const3bc_abc' => {
        desc    => 'index of a long string of "bc"s against a 3 char const substr "abc"',
        setup   => 'my $x = "bc" x 500',
        code    => 'index $x, "abc"',
    },
    'func::index::utf8_position_1' => {
        desc    => 'index of a utf8 string, matching at position 1',
        setup   => 'my $x = "abc". chr(0x100); chop $x',
        code    => 'index $x, "b"',
    },


    # JOIN


    'func::join::empty_l_ll' => {
        setup   => 'my $lex; my $lex1 = "abcd"; my $lex2 = "wxyz"',
        code    => '$lex = join "", $lex1, $lex2',
    },


    # KEYS


    'func::keys::lex::void_cxt_empty' => {
        desc    => ' keys() on an empty lexical hash in void context',
        setup   => 'my %h = ()',
        code    => 'keys %h',
    },
    'func::keys::lex::void_cxt' => {
        desc    => ' keys() on a non-empty lexical hash in void context',
        setup   => 'my %h = qw(aardvark 1 banana 2 cucumber 3)',
        code    => 'keys %h',
    },
    'func::keys::lex::bool_cxt_empty' => {
        desc    => ' keys() on an empty lexical hash in bool context',
        setup   => 'my %h = ()',
        code    => '!keys %h',
    },
    'func::keys::lex::bool_cxt' => {
        desc    => ' keys() on a non-empty lexical hash in bool context',
        setup   => 'my %h = qw(aardvark 1 banana 2 cucumber 3)',
        code    => '!keys %h',
    },
    'func::keys::lex::scalar_cxt_empty' => {
        desc    => ' keys() on an empty lexical hash in scalar context',
        setup   => 'my $k; my %h = ()',
        code    => '$k = keys %h',
    },
    'func::keys::lex::scalar_cxt' => {
        desc    => ' keys() on a non-empty lexical hash in scalar context',
        setup   => 'my $k; my %h = qw(aardvark 1 banana 2 cucumber 3)',
        code    => '$k = keys %h',
    },
    'func::keys::lex::list_cxt_empty' => {
        desc    => ' keys() on an empty lexical hash in list context',
        setup   => 'my %h = ()',
        code    => '() = keys %h',
    },
    'func::keys::lex::list_cxt' => {
        desc    => ' keys() on a non-empty lexical hash in list context',
        setup   => 'my %h = qw(aardvark 1 banana 2 cucumber 3)',
        code    => '() = keys %h',
    },

    'func::keys::pkg::void_cxt_empty' => {
        desc    => ' keys() on an empty package hash in void context',
        setup   => 'our %h = ()',
        code    => 'keys %h',
    },
    'func::keys::pkg::void_cxt' => {
        desc    => ' keys() on a non-empty package hash in void context',
        setup   => 'our %h = qw(aardvark 1 banana 2 cucumber 3)',
        code    => 'keys %h',
    },
    'func::keys::pkg::bool_cxt_empty' => {
        desc    => ' keys() on an empty package hash in bool context',
        setup   => 'our %h = ()',
        code    => '!keys %h',
    },
    'func::keys::pkg::bool_cxt' => {
        desc    => ' keys() on a non-empty package hash in bool context',
        setup   => 'our %h = qw(aardvark 1 banana 2 cucumber 3)',
        code    => '!keys %h',
    },
    'func::keys::pkg::scalar_cxt_empty' => {
        desc    => ' keys() on an empty package hash in scalar context',
        setup   => 'my $k; our %h = ()',
        code    => '$k = keys %h',
    },
    'func::keys::pkg::scalar_cxt' => {
        desc    => ' keys() on a non-empty package hash in scalar context',
        setup   => 'my $k; our %h = qw(aardvark 1 banana 2 cucumber 3)',
        code    => '$k = keys %h',
    },
    'func::keys::pkg::list_cxt_empty' => {
        desc    => ' keys() on an empty package hash in list context',
        setup   => 'our %h = ()',
        code    => '() = keys %h',
    },
    'func::keys::pkg::list_cxt' => {
        desc    => ' keys() on a non-empty package hash in list context',
        setup   => 'our %h = qw(aardvark 1 banana 2 cucumber 3)',
        code    => '() = keys %h',
    },


    'func::length::bool0' => {
        desc    => 'length==0 in boolean context',
        setup   => 'my $s = "";',
        code    => '!length($s);',
    },
    'func::length::bool10' => {
        desc    => 'length==10 in boolean context',
        setup   => 'my $s = "abcdefghijk";',
        code    => '!length($s);',
    },
    'func::length::scalar10' => {
        desc    => 'length==10 in scalar context',
        setup   => 'my $p; my $s = "abcdefghijk";',
        code    => '$p = length($s);',
    },
    'func::length::bool0_utf8' => {
        desc    => 'utf8 string length==0 in boolean context',
        setup   => 'my $s = "\x{100}"; chop $s;',
        code    => '!length($s);',
    },
    'func::length::bool10_utf8' => {
        desc    => 'utf8 string length==10 in boolean context',
        setup   => 'my $s = "abcdefghij\x{100}";',
        code    => '!length($s);',
    },
    'func::length::scalar10_utf8' => {
        desc    => 'utf8 string length==10 in scalar context',
        setup   => 'my $p; my $s = "abcdefghij\x{100}";',
        code    => '$p = length($s);',
    },

    'func::pos::bool0' => {
        desc    => 'pos==0 in boolean context',
        setup   => 'my $s = "abc"; pos($s) = 0',
        code    => '!pos($s);',
    },
    'func::pos::bool10' => {
        desc    => 'pos==10 in boolean context',
        setup   => 'my $s = "abcdefghijk"; pos($s) = 10',
        code    => '!pos($s);',
    },
    'func::pos::scalar10' => {
        desc    => 'pos==10 in scalar context',
        setup   => 'my $p; my $s = "abcdefghijk"; pos($s) = 10',
        code    => '$p = pos($s);',
    },

    'func::ref::notaref_bool' => {
        desc    => 'ref($notaref) in boolean context',
        setup   => 'my $r = "boo"',
        code    => '!ref $r',
    },
    'func::ref::ref_bool' => {
        desc    => 'ref($ref) in boolean context',
        setup   => 'my $r = []',
        code    => '!ref $r',
    },
    'func::ref::blessedref_bool' => {
        desc    => 'ref($blessed_ref) in boolean context',
        setup   => 'my $r = bless []',
        code    => '!ref $r',
    },

    'func::ref::notaref' => {
        desc    => 'ref($notaref) in scalar context',
        setup   => 'my $x; my $r = "boo"',
        code    => '$x = ref $r',
    },
    'func::ref::ref' => {
        desc    => 'ref($ref) in scalar context',
        setup   => 'my $x; my $r = []',
        code    => '$x = ref $r',
    },
    'func::ref::blessedref' => {
        desc    => 'ref($blessed_ref) in scalar context',
        setup   => 'my $x; my $r = bless []',
        code    => '$x = ref $r',
    },



    'func::sort::num' => {
        desc    => 'plain numeric sort',
        setup   => 'my (@a, @b); @a = reverse 1..10;',
        code    => '@b = sort { $a <=> $b } @a',
    },
    'func::sort::num_block' => {
        desc    => 'codeblock numeric sort',
        setup   => 'my (@a, @b); @a = reverse 1..10;',
        code    => '@b = sort { $a + 1 <=> $b + 1 } @a',
    },
    'func::sort::num_fn' => {
        desc    => 'function numeric sort',
        setup   => 'sub f { $a + 1 <=> $b + 1 } my (@a, @b); @a = reverse 1..10;',
        code    => '@b = sort f @a',
    },
    'func::sort::str' => {
        desc    => 'plain string sort',
        setup   => 'my (@a, @b); @a = reverse "a".."j";',
        code    => '@b = sort { $a cmp $b } @a',
    },
    'func::sort::str_block' => {
        desc    => 'codeblock string sort',
        setup   => 'my (@a, @b); @a = reverse "a".."j";',
        code    => '@b = sort { ($a . "") cmp ($b . "") } @a',
    },
    'func::sort::str_fn' => {
        desc    => 'function string sort',
        setup   => 'sub f { ($a . "") cmp ($b . "") } my (@a, @b); @a = reverse  "a".."j";',
        code    => '@b = sort f @a',
    },

    'func::sort::num_inplace' => {
        desc    => 'plain numeric sort in-place',
        setup   => 'my @a = reverse 1..10;',
        code    => '@a = sort { $a <=> $b } @a',
    },
    'func::sort::num_block_inplace' => {
        desc    => 'codeblock numeric sort in-place',
        setup   => 'my @a = reverse 1..10;',
        code    => '@a = sort { $a + 1 <=> $b + 1 } @a',
    },
    'func::sort::num_fn_inplace' => {
        desc    => 'function numeric sort in-place',
        setup   => 'sub f { $a + 1 <=> $b + 1 } my @a = reverse 1..10;',
        code    => '@a = sort f @a',
    },
    'func::sort::str_inplace' => {
        desc    => 'plain string sort in-place',
        setup   => 'my @a = reverse "a".."j";',
        code    => '@a = sort { $a cmp $b } @a',
    },
    'func::sort::str_block_inplace' => {
        desc    => 'codeblock string sort in-place',
        setup   => 'my @a = reverse "a".."j";',
        code    => '@a = sort { ($a . "") cmp ($b . "") } @a',
    },
    'func::sort::str_fn_inplace' => {
        desc    => 'function string sort in-place',
        setup   => 'sub f { ($a . "") cmp ($b . "") } my @a = reverse  "a".."j";',
        code    => '@a = sort f @a',
    },


    'func::split::vars' => {
        desc    => 'split into two lexical vars',
        setup   => 'my $s = "abc:def";',
        code    => 'my ($x, $y) = split /:/, $s, 2;',
    },

    'func::split::array' => {
        desc    => 'split into a lexical array',
        setup   => 'my @a; my $s = "abc:def";',
        code    => '@a = split /:/, $s, 2;',
    },
    'func::split::myarray' => {
        desc    => 'split into a lexical array declared in the assign',
        setup   => 'my $s = "abc:def";',
        code    => 'my @a = split /:/, $s, 2;',
    },
    'func::split::arrayexpr' => {
        desc    => 'split into an @{$expr} ',
        setup   => 'my $s = "abc:def"; my $r = []',
        code    => '@$r = split /:/, $s, 2;',
    },
    'func::split::arraylist' => {
        desc    => 'split into an array with extra arg',
        setup   => 'my @a; my $s = "abc:def";',
        code    => '@a = (split(/:/, $s, 2), 1);',
    },

    # SPRINTF


    'func::sprintf::d' => {
        desc    => '%d',
        setup   => 'my $s; my $a1 = 1234;',
        code    => '$s = sprintf "%d", $a1',
    },
    'func::sprintf::d8' => {
        desc    => '%8d',
        setup   => 'my $s; my $a1 = 1234;',
        code    => '$s = sprintf "%8d", $a1',
    },
    'func::sprintf::foo_d8' => {
        desc    => 'foo=%8d',
        setup   => 'my $s; my $a1 = 1234;',
        code    => '$s = sprintf "foo=%8d", $a1',
    },

    'func::sprintf::f0' => {
        # "%.0f" is very special-cased
        desc    => 'sprintf "%.0f"',
        setup   => 'my $s; my $a1 = 123.456;',
        code    => '$s = sprintf "%.0f", $a1',
    },
    'func::sprintf::foo_f0' => {
        # "...%.0f..." is special-cased
        desc    => 'sprintf "foo=%.0f"',
        setup   => 'my $s; my $a1 = 123.456;',
        code    => '$s = sprintf "foo=%.0f\n", $a1',
    },
    'func::sprintf::foo_f93' => {
        desc    => 'foo=%9.3f',
        setup   => 'my $s; my $a1 = 123.456;',
        code    => '$s = sprintf "foo=%9.3f\n", $a1',
    },

    'func::sprintf::g9' => {
        # "...%.NNNg..." is special-cased
        desc    => '%.9g',
        setup   => 'my $s; my $a1 = 123.456;',
        code    => '$s = sprintf "%.9g", $a1',
    },
    'func::sprintf::foo_g9' => {
        # "...%.NNNg..." is special-cased
        desc    => 'foo=%.9g',
        setup   => 'my $s; my $a1 = 123.456;',
        code    => '$s = sprintf "foo=%.9g\n", $a1',
    },
    'func::sprintf::foo_g93' => {
        desc    => 'foo=%9.3g',
        setup   => 'my $s; my $a1 = 123.456;',
        code    => '$s = sprintf "foo=%9.3g\n", $a1',
    },

    'func::sprintf::s' => {
        desc    => '%s',
        setup   => 'my $s; my $a1 = "abcd";',
        code    => '$s = sprintf "%s", $a1',
    },
    'func::sprintf::foo_s' => {
        desc    => 'foo=%s',
        setup   => 'my $s; my $a1 = "abcd";',
        code    => '$s = sprintf "foo=%s", $a1',
    },
    'func::sprintf::mixed_utf8_sss' => {
        desc    => 'foo=%s bar=%s baz=%s',
        setup   => 'my $s;my $a = "ab\x{100}cd"; my $b = "efg"; my $c = "h\x{101}ij"',
        code    => '$s = sprintf "foo=%s bar=%s baz=%s", $a, $b, $c',
    },

    # sprint that's likely to be optimised to an OP_MULTICONCAT

    'func::sprintf::l' => {
        setup   => 'my $lex1 = "abcd"',
        code    => 'sprintf "%s", $lex1',
    },
    'func::sprintf::g_l' => {
        setup   => 'our $pkg; my $lex1 = "abcd"',
        code    => '$pkg = sprintf "%s", $lex1',
    },
    'func::sprintf::g_append_l' => {
        setup   => 'our $pkg; my $lex1 = "abcd"',
        pre     => '$pkg = "pqrs"',
        code    => '$pkg .= sprintf "%s", $lex1',
    },
    'func::sprintf::g_ll' => {
        setup   => 'our $pkg; my $lex1 = "abcd"; my $lex2 = "wxyz"',
        code    => '$pkg = sprintf "%s%s", $lex1, $lex2',
    },
    'func::sprintf::g_append_ll' => {
        setup   => 'our $pkg; my $lex1 = "abcd"; my $lex2 = "wxyz"',
        pre     => '$pkg = "pqrs"',
        code    => '$pkg .= sprintf "%s%s", $lex1, $lex2',
    },
    'func::sprintf::g_cl' => {
        setup   => 'our $pkg; my $lex1 = "abcd"',
        code    => '$pkg = sprintf "foo=%s", $lex1',
    },
    'func::sprintf::g_clclc' => {
        setup   => 'our $pkg; my $lex1 = "abcd"; my $lex2 = "wxyz"',
        code    => '$pkg = sprintf "foo=%s bar=%s\n", $lex1, $lex2',
    },

    'func::sprintf::l_l' => {
        setup   => 'my $lex; my $lex1 = "abcd"',
        code    => '$lex = sprintf "%s", $lex1',
    },
    'func::sprintf::l_append_l' => {
        setup   => 'my $lex; my $lex1 = "abcd"',
        pre     => '$lex = "pqrs"',
        code    => '$lex .= sprintf "%s", $lex1',
    },
    'func::sprintf::ll' => {
        setup   => 'my $lex1 = "abcd"; my $lex2 = "wxyz"',
        code    => 'sprintf "%s%s", $lex1, $lex2',
    },
    'func::sprintf::l_ll' => {
        setup   => 'my $lex; my $lex1 = "abcd"; my $lex2 = "wxyz"',
        code    => '$lex = sprintf "%s%s", $lex1, $lex2',
    },
    'func::sprintf::l_append_ll' => {
        setup   => 'my $lex; my $lex1 = "abcd"; my $lex2 = "wxyz"',
        pre     => '$lex = "pqrs"',
        code    => '$lex .= sprintf "%s%s", $lex1, $lex2',
    },
    'func::sprintf::l_cl' => {
        setup   => 'my $lex; my $lex1 = "abcd"',
        code    => '$lex = sprintf "foo=%s", $lex1',
    },
    'func::sprintf::l_clclc' => {
        setup   => 'my $lex; my $lex1 = "abcd"; my $lex2 = "wxyz"',
        code    => '$lex = sprintf "foo=%s bar=%s\n", $lex1, $lex2',
    },

    'func::sprintf::m_l' => {
        setup   => 'my $lex1 = "abcd"',
        code    => 'my $lex = sprintf "%s", $lex1',
    },
    'func::sprintf::m_ll' => {
        setup   => 'my $lex1 = "abcd"; my $lex2 = "wxyz"',
        code    => 'my $lex = sprintf "%s%s", $lex1, $lex2',
    },
    'func::sprintf::m_cl' => {
        setup   => 'my $lex1 = "abcd"',
        code    => 'my $lex = sprintf "foo=%s", $lex1',
    },
    'func::sprintf::m_clclc' => {
        setup   => 'my $lex1 = "abcd"; my $lex2 = "wxyz"',
        code    => 'my $lex = sprintf "foo=%s bar=%s\n", $lex1, $lex2',
    },

    'func::sprintf::utf8__l_lll' => {
        desc    => '$s = sprintf("foo=%s bar=%s baz=%s", $a, $b, $c) where $a,$c are utf8',
        setup   => 'my $s; my $a = "ab\x{100}cde"; my $b = "fghij"; my $c = "\x{101}klmn"',
        code    => '$s = sprintf "foo=%s bar=%s baz=%s", $a, $b, $c',
    },


    # S///

    'func::subst::bool' => {
        desc    => 's/// in boolean context',
        setup   => '',
        code    => '$_ = "aaa"; !s/./x/g;'
    },


    'func::values::scalar_cxt_empty' => {
        desc    => ' values() on an empty hash in scalar context',
        setup   => 'my $k; my %h = ()',
        code    => '$k = values %h',
    },
    'func::values::scalar_cxt' => {
        desc    => ' values() on a non-empty hash in scalar context',
        setup   => 'my $k; my %h = qw(aardvark 1 banana 2 cucumber 3)',
        code    => '$k = values %h',
    },
    'func::values::list_cxt_empty' => {
        desc    => ' values() on an empty hash in list context',
        setup   => 'my %h = ()',
        code    => '() = values %h',
    },
    'func::values::list_cxt' => {
        desc    => ' values() on a non-empty hash in list context',
        setup   => 'my %h = qw(aardvark 1 banana 2 cucumber 3)',
        code    => '() = values %h',
    },



    'loop::block' => {
        desc    => 'empty basic loop',
        setup   => '',
        code    => '{1;}',
    },

    'loop::do' => {
        desc    => 'basic do block',
        setup   => 'my $x; my $y = 2;',
        code    => '$x = do {1; $y}', # the ';' stops the do being optimised
    },

    'loop::for::my_range1' => {
        desc    => 'empty for loop with my var and 1 integer range',
        setup   => '',
        code    => 'for my $x (1..1) {}',
    },
    'loop::for::lex_range1' => {
        desc    => 'empty for loop with lexical var and 1 integer range',
        setup   => 'my $x;',
        code    => 'for $x (1..1) {}',
    },
    'loop::for::pkg_range1' => {
        desc    => 'empty for loop with package var and 1 integer range',
        setup   => '$x = 1;',
        code    => 'for $x (1..1) {}',
    },
    'loop::for::defsv_range1' => {
        desc    => 'empty for loop with $_ and integer 1 range',
        setup   => ';',
        code    => 'for (1..1) {}',
    },
    'loop::for::my_range4' => {
        desc    => 'empty for loop with my var and 4 integer range',
        setup   => '',
        code    => 'for my $x (1..4) {}',
    },
    'loop::for::lex_range4' => {
        desc    => 'empty for loop with lexical var and 4 integer range',
        setup   => 'my $x;',
        code    => 'for $x (1..4) {}',
    },
    'loop::for::pkg_range4' => {
        desc    => 'empty for loop with package var and 4 integer range',
        setup   => '$x = 1;',
        code    => 'for $x (1..4) {}',
    },
    'loop::for::defsv_range4' => {
        desc    => 'empty for loop with $_ and integer 4 range',
        setup   => ';',
        code    => 'for (1..4) {}',
    },

    'loop::for::my_list1' => {
        desc    => 'empty for loop with my var and 1 integer list',
        setup   => '',
        code    => 'for my $x (1) {}',
    },
    'loop::for::lex_list1' => {
        desc    => 'empty for loop with lexical var and 1 integer list',
        setup   => 'my $x;',
        code    => 'for $x (1) {}',
    },
    'loop::for::pkg_list1' => {
        desc    => 'empty for loop with package var and 1 integer list',
        setup   => '$x = 1;',
        code    => 'for $x (1) {}',
    },
    'loop::for::defsv_list1' => {
        desc    => 'empty for loop with $_ and integer 1 list',
        setup   => ';',
        code    => 'for (1) {}',
    },
    'loop::for::my_list4' => {
        desc    => 'empty for loop with my var and 4 integer list',
        setup   => '',
        code    => 'for my $x (1,2,3,4) {}',
    },
    'loop::for::lex_list4' => {
        desc    => 'empty for loop with lexical var and 4 integer list',
        setup   => 'my $x;',
        code    => 'for $x (1,2,3,4) {}',
    },
    'loop::for::pkg_list4' => {
        desc    => 'empty for loop with package var and 4 integer list',
        setup   => '$x = 1;',
        code    => 'for $x (1,2,3,4) {}',
    },
    'loop::for::defsv_list4' => {
        desc    => 'empty for loop with $_ and integer 4 list',
        setup   => '',
        code    => 'for (1,2,3,4) {}',
    },

    'loop::for::my_array1' => {
        desc    => 'empty for loop with my var and 1 integer array',
        setup   => 'my @a = (1);',
        code    => 'for my $x (@a) {}',
    },
    'loop::for::lex_array1' => {
        desc    => 'empty for loop with lexical var and 1 integer array',
        setup   => 'my $x; my @a = (1);',
        code    => 'for $x (@a) {}',
    },
    'loop::for::pkg_array1' => {
        desc    => 'empty for loop with package var and 1 integer array',
        setup   => '$x = 1; my @a = (1);',
        code    => 'for $x (@a) {}',
    },
    'loop::for::defsv_array1' => {
        desc    => 'empty for loop with $_ and integer 1 array',
        setup   => 'my @a = (@a);',
        code    => 'for (1) {}',
    },
    'loop::for::my_array4' => {
        desc    => 'empty for loop with my var and 4 integer array',
        setup   => 'my @a = (1..4);',
        code    => 'for my $x (@a) {}',
    },
    'loop::for::lex_array4' => {
        desc    => 'empty for loop with lexical var and 4 integer array',
        setup   => 'my $x; my @a = (1..4);',
        code    => 'for $x (@a) {}',
    },
    'loop::for::pkg_array4' => {
        desc    => 'empty for loop with package var and 4 integer array',
        setup   => '$x = 1; my @a = (1..4);',
        code    => 'for $x (@a) {}',
    },
    'loop::for::defsv_array4' => {
        desc    => 'empty for loop with $_ and integer 4 array',
        setup   => 'my @a = (1..4);',
        code    => 'for (@a) {}',
    },

    'loop::for::next4' => {
        desc    => 'for loop containing only next with my var and integer 4 array',
        setup   => 'my @a = (1..4);',
        code    => 'for my $x (@a) {next}',
    },

    'loop::grep::expr_3int' => {
        desc    => 'grep $_ > 0, 1,2,3',
        setup   => 'my @a',
        code    => '@a = grep $_ > 0, 1,2,3',
    },

    'loop::grep::block_3int' => {
        desc    => 'grep { 1; $_ > 0} 1,2,3',
        setup   => 'my @a',
        code    => '@a = grep { 1; $_ > 0} 1,2,3',
    },

    'loop::map::expr_3int' => {
        desc    => 'map $_+1, 1,2,3',
        setup   => 'my @a',
        code    => '@a = map $_+1, 1,2,3',
    },

    'loop::map::block_3int' => {
        desc    => 'map { 1; $_+1} 1,2,3',
        setup   => 'my @a',
        code    => '@a = map { 1; $_+1} 1,2,3',
    },

    'loop::while::i1' => {
        desc    => 'empty while loop 1 iteration',
        setup   => 'my $i = 0;',
        code    => 'while (++$i % 2) {}',
    },
    'loop::while::i4' => {
        desc    => 'empty while loop 4 iterations',
        setup   => 'my $i = 0;',
        code    => 'while (++$i % 4) {}',
    },


    'regex::anyof_plus::anchored' => {
        setup   => '$_ = "a" x 100;',
        code    => '/^[acgt]+/',
    },
    'regex::anyof_plus::floating' => {
        desc    => '/[acgt]+where match starts at position 0 for 100 chars/',
        setup   => '$_ = "a" x 100;',
        code    => '/[acgt]+/',
    },
    'regex::anyof_plus::floating_away' => {
        desc    => '/[acgt]+/ where match starts at position 100 for 100 chars',
        setup   => '$_ = ("0" x 100) . ("a" x 100);',
        code    => '/[acgt]+/',
    },

    'regex::whilem::min_captures_fail' => {
        desc    => '/WHILEM with anon-greedy match and captures that fails',
        setup   => '$_ = ("a" x 20)',
        code    => '/^(?:(.)(.))*?[XY]/',
    },
    'regex::whilem::max_captures_fail' => {
        desc    => '/WHILEM with a greedy match and captures that fails',
        setup   => '$_ = ("a" x 20)',
        code    => '/^(?:(.)(.))*[XY]/',
    },
];