1berry/ruby
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Add peephole optimizer for newarray(2)/expandarray(2, 0) -> swap

Browse Source 
An optimization for multiple assignment in the popped case to avoid
array allocation was lost in my fix to make multiple assignment follow
left-to-right evaluation (50c54d40a81bb2a4794a6be5f1861152900b4fed).

Before, in the two element case, swap was used.  Afterward, newarray(2)
and expandarray(2, 0) were used, which is the same as swap, with the
addition of an unnecessary allocation.

Because this issue is not specific to multiple assignment, and the
multiple assignment code is complex enough as it is, this updates
the peephole optimizer to do the newarray(2)/expandarray(2, 0) -> swap
conversion.

A more general optimization pass for
newarray(X)/expandarray(X, 0) -> reverse(X) will follow, but that
requires readding the reverse instruction.
This commit is contained in:
Jeremy Evans 2022-07-20 12:16:24 -07:00
parent 3569d13095
commit 9f8abd28ba
Notes: git 2022-08-10 14:20:08 +09:00 
Merged: https://github.com/ruby/ruby/pull/6158
1 changed files with 19 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
compile.c
View File

@ -3332,6 +3332,25 @@ iseq_peephole_optimize(rb_iseq_t *iseq, LINK_ELEMENT *list, const int do_tailcal
}
}
if (IS_INSN_ID(iobj, newarray)) {
LINK_ELEMENT *next = iobj->link.next;
if (IS_INSN(next) && IS_INSN_ID(next, expandarray) &&
OPERAND_AT(iobj, 0) == OPERAND_AT(next, 0) &&
OPERAND_AT(next, 1) == INT2FIX(0)) {
/*
* newarray 2
* expandarray 2, 0
* =>
* swap
*/
if (OPERAND_AT(iobj, 0) == INT2FIX(2)) {
ELEM_REMOVE(next);
INSN_OF(iobj) = BIN(swap);
iobj->operand_size = 0;
}
}
}
if (IS_INSN_ID(iobj, anytostring)) {
LINK_ELEMENT *next = iobj->link.next;
/*