ZJIT: Optimize frozen array subscript #13666
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tekknolagi
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k0kubun
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Jun 20, 2025
| @@ -1309,6 +1310,25 @@ impl Function { | |||
| } | |||
| } | |||
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| fn try_rewrite_subscript(&mut self, block: BlockId, orig_insn_id: InsnId, self_val: InsnId, idx_val: InsnId) { | |||
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| fn try_rewrite_subscript(&mut self, block: BlockId, orig_insn_id: InsnId, self_val: InsnId, idx_val: InsnId) { | |
| fn try_rewrite_aref(&mut self, block: BlockId, orig_insn_id: InsnId, self_val: InsnId, idx_val: InsnId) { |
#[] is called aref very consistently in the CRuby codebase, so calling it differently could confuse contributors, at least including myself.
k0kubun
reviewed
Jun 20, 2025
| bb0(v0:BasicObject): | ||
| PatchPoint BOPRedefined(ARRAY_REDEFINED_OP_FLAG, BOP_FREEZE) | ||
| PatchPoint BOPRedefined(ARRAY_REDEFINED_OP_FLAG, BOP_AREF) | ||
| v11:NilClassExact = Const Value(nil) |
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Is it intentional that the result is nil? -1 is 6, -2 is 5, so -3 should be 4.
$ ruby -e 'p [4,5,6].freeze[-3]'
4
You picked rb_ary_elt for your implementation, but as the comment above the function says, the behavior is different from Array#[].
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Nice catch, thank you
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If we have a frozen array
[..., a, ...]and a compile-time fixnum indexi, we can do the array load at compile-time.