Fix condition for unreachable code in IRCode conversion
#53512
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Needs a test before this merges, but otherwise this should be good to go. As far as I can tell, this bug is present on 1.9 but I believe it is being masked by a difference in our 21 ┄ %58 = φᶜ (%85)::Base.GenericCondition{ReentrantLock}
│ φ (#20 => %59, #2 => %1)::Base.GenericCondition{ReentrantLock}
│ %71 = φᶜ (%86, %98)::Core.Compiler.MaybeUndef(Core.Const(nothing))
│ φ (#20 => %73, #2 => #undef)::Core.Compiler.MaybeUndef(Union{})
│ %76 = φᶜ (%87, %103)::Core.Compiler.MaybeUndef(Core.Const(nothing))
│ φ (#20 => %78, #2 => #undef)::Core.Compiler.MaybeUndef(Union{})
│ %81 = φᶜ (%88)::Core.Compiler.MaybeUndef(Union{})
│ φ (#20 => %82, #2 => #undef)::Core.Compiler.MaybeUndef(Union{})
└─── $(Expr(:leave, 1)) |
vtjnash
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Feb 28, 2024
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Maybe merge this @topolarity, while we're waiting on #53553? |
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This is a partial back-port of JuliaLang#50924, where we discovered that the optimizer would ignore: 1. must-throw `%XX = SlotNumber(_)` statements 2. must-throw `goto #bb if not %x` statements when re-building the CFG during IRCode conversion. This is mostly harmless, except that in the case of (1) we can accidentally fall through the statically deleted (`Const()`-wrapped) code from inference and observe a control-flow edge that never should have existed, such as an edge into a catch block. Such an edge is invalid semantically and breaks our SSA conversion. This one-line change fixes (1) but not (2), which is enough for IR validity. We should follow-up with a tweak to `compute_basic_blocks` to enforce this requirement. The test added here is very brittle, but it's better than nothing until we have utilities to provide hand-written (pre-optimizer) IR and pass it through part of our pipeline.
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…53512) This is a partial back-port of JuliaLang#50924, where we discovered that the optimizer would ignore: 1. must-throw `%XX = SlotNumber(_)` statements 2. must-throw `goto #bb if not %x` statements This is mostly harmless, except that in the case of (1) we can accidentally fall through the statically deleted (`Const()`-wrapped) code from inference and end up observing a control-flow edge that never existed. If the spurious edge is to a catch block, then the edge is invalid semantically and breaks our SSA conversion. This one-line change fixes (1) but not (2), which is enough for IR validity. Resolves part of JuliaLang#53366. (cherry picked from commit 035d17a)
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This is a partial back-port of #50924, where we discovered that the optimizer would ignore:
%XX = SlotNumber(_)statementsgoto #bb if not %xstatementsThis is mostly harmless, except that in the case of (1) we can accidentally fall through the statically deleted (
Const()-wrapped) code from inference and end up observing a control-flow edge that never existed.If the spurious edge is to a catch block, then the edge is invalid semantically and breaks our SSA conversion.
This one-line change fixes (1) but not (2), which is enough for IR validity.
Resolves part of #53366.