Remove Cifthenelse #3859
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Remove Cifthenelse #3859
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This is based on #3855 |
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Ah but the first bullet point isn't quite right: the " |
lthls
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Apr 15, 2025
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gretay-js
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| @@ -871,6 +871,11 @@ let[@inline] get_const = function | |||
| | Cconst_natint (i, _) -> Some i | |||
| | _ -> None | |||
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| let ifthenelse (cond, then_dbg, then_, else_dbg, else_, dbg) = | |||
| (* This case is matched on in [Cfg_selection] *) | |||
| let cond = tag_int (Cop (Ccmpi Cne, [cond; Cconst_int (1, dbg)], dbg)) dbg in | |||
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why do we need tag_int around this expression?
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This is to bring the Cmm language further in line with Flambda 2.
I think this should be ok, but will look at the generated code. Two problems might be:
Cmm_helpers.ifthenelse, what will happen? This should be fine if the results of e.g.Iinttestare in{0, 1}, but is that guaranteed?Cswitchon{0, 1}gets caught by the new pattern in instruction selection, will the code be worse? It's unclear such a switch would ever be generated anyway (seeTo_cmm_expr.switch).