[perl #113710] Make __SUB__ work in sort block

When the peephole optimiser encounters a __SUB__, it looks to see
whether the current sub is clonable.  If it is not, it inlines the
__SUB__ as a const op.

This works most of the time.  A forward declaration will cause the sub
definition to reuse the existing stub.  When that happens, the sub
visible during compilation in PL_compcv is not the sub that the
op tree will finally be attached to.  But the peephole optimiser
is called after that, with PL_compcv set to the other CV (what
was a stub).

ck_sort was calling the peephole optimiser on the sort block ahead of
time.  So this caused __SUB__ to point to the wrong subroutine.

By removing the CALL_PEEP call from ck_sort and adding logic to the
peephole optimiser itself to traverse the sort block (it is not in the
usual op_next chain), this bug is eliminated.

I modified the DEFER macro to work as a single statement.  You don’t
want to know how much time I spent debugging the bus errors that were
occurring because if(foo) DEFER; didn’t do what I though.

It turns out that grepstart and mapstart, which also use ck_sort,
had their blocks go through the peephole optimiser twice, because
grepwhile already has special-casing in the peephole optimiser.

This also has the side-effect of making map and grep slightly more
efficient, in that they no longer execute a scope op (which is just
pp_null).  By temporarily disconnecting the subtree before running the
optimiser, ck_sort was hiding a possible optimisation (skipping the
scope op).

2 files changed, 0 insertions, 14 deletions

diff --git a/ext/B/t/f_map.t b/ext/B/t/f_map.t
index 2fa2ec95eb..4506543411 100644
--- a/ext/B/t/f_map.t
+++ b/ext/B/t/f_map.t
@@ -247,7 +247,6 @@ checkOptree(note   => q{},
 # b      <@> stringify[t5] sK/1
 # c      <$> const[IV 1] s
 # d      <@> list lK
-# -      <@> scope lK
 #            goto 7
 # e  <0> pushmark s
 # f  <#> gv[*hash] s
@@ -268,7 +267,6 @@ EOT_EOT
 # b      <@> stringify[t3] sK/1
 # c      <$> const(IV 1) s
 # d      <@> list lK
-# -      <@> scope lK
 #            goto 7
 # e  <0> pushmark s
 # f  <$> gv(*hash) s
@@ -301,7 +299,6 @@ checkOptree(note   => q{},
 # b      <@> stringify[t5] sK/1
 # c      <$> const[IV 1] s
 # d      <@> list lKP
-# -      <@> scope lK
 #            goto 7
 # e  <0> pushmark s
 # f  <#> gv[*hash] s
@@ -322,7 +319,6 @@ EOT_EOT
 # b      <@> stringify[t3] sK/1
 # c      <$> const(IV 1) s
 # d      <@> list lKP
-# -      <@> scope lK
 #            goto 7
 # e  <0> pushmark s
 # f  <$> gv(*hash) s
@@ -354,7 +350,6 @@ checkOptree(note   => q{},
 # a      <1> lc[t4] sK/1
 # b      <$> const[IV 1] s
 # c      <@> list lK
-# -      <@> scope lK
 #            goto 7
 # d  <0> pushmark s
 # e  <#> gv[*hash] s
@@ -374,7 +369,6 @@ EOT_EOT
 # a      <1> lc[t2] sK/1
 # b      <$> const(IV 1) s
 # c      <@> list lK
-# -      <@> scope lK
 #            goto 7
 # d  <0> pushmark s
 # e  <$> gv(*hash) s
diff --git a/ext/B/t/f_sort.t b/ext/B/t/f_sort.t
index 58a8cf2eed..f17976f11f 100644
--- a/ext/B/t/f_sort.t
+++ b/ext/B/t/f_sort.t
@@ -520,7 +520,6 @@ checkOptree(name   => q{Compound sort/map Expression },
 # o      <1> rv2av[t4] sKR/1
 # p      <$> const[IV 0] s
 # q      <2> aelem sK/2
-# -      <@> scope lK
 #            goto l
 # r  <0> pushmark s
 # s  <#> gv[*new] s
@@ -555,7 +554,6 @@ EOT_EOT
 # o      <1> rv2av[t2] sKR/1
 # p      <$> const(IV 0) s
 # q      <2> aelem sK/2
-# -      <@> scope lK
 #            goto l
 # r  <0> pushmark s
 # s  <$> gv(*new) s
@@ -790,7 +788,6 @@ checkOptree(note   => q{},
 # 9      <#> gvsv[*_] s
 # a      <#> gvsv[*_] s
 # b      <2> eq sK/2
-# -      <@> scope sK
 #            goto 8
 # c  <@> sort lK/NUM
 # d  <0> pushmark s
@@ -810,7 +807,6 @@ EOT_EOT
 # 9      <$> gvsv(*_) s
 # a      <$> gvsv(*_) s
 # b      <2> eq sK/2
-# -      <@> scope sK
 #            goto 8
 # c  <@> sort lK/NUM
 # d  <0> pushmark s
@@ -869,7 +865,6 @@ checkOptree(note   => q{},
 # 8      <#> gvsv[*_] s
 # 9      <#> gvsv[*_] s
 # a      <2> eq sK/2
-# -      <@> scope sK
 #            goto 7
 # b  <@> sort K/NUM
 # c  <1> leavesub[1 ref] K/REFC,1
@@ -884,7 +879,6 @@ EOT_EOT
 # 8      <$> gvsv(*_) s
 # 9      <$> gvsv(*_) s
 # a      <2> eq sK/2
-# -      <@> scope sK
 #            goto 7
 # b  <@> sort K/NUM
 # c  <1> leavesub[1 ref] K/REFC,1
@@ -942,7 +936,6 @@ checkOptree(note   => q{},
 # 8      <#> gvsv[*_] s
 # 9      <#> gvsv[*_] s
 # a      <2> eq sK/2
-# -      <@> scope sK
 #            goto 7
 # b  <@> sort sK/NUM
 # c  <#> gvsv[*s] s
@@ -959,7 +952,6 @@ EOT_EOT
 # 8      <$> gvsv(*_) s
 # 9      <$> gvsv(*_) s
 # a      <2> eq sK/2
-# -      <@> scope sK
 #            goto 7
 # b  <@> sort sK/NUM
 # c  <$> gvsv(*s) s