codegen: mark write barrier field load as volatile #59559
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vtjnash
added
GC
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This LGTM, there's very little optimizations that are legal around these GC stores at that point |
This is as an alternative to changing all allocation functions to mutating all memory and returning an aliasing pointer. This operates usually late in the pipeline, so either should not make much difference, but I think it should suffice to mark this volatile to prevent any de-duplication of this load, and this should also be most conservative. Fixes #59547 Written by Claude.
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why volitile rather than sequentially consistent? |
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There aren't any atomic requirements there. It just can't assume the value that was there cannot change. |
KristofferC
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This is as an alternative to changing all allocation functions to mutating all memory and returning an aliasing pointer. This operates usually late in the pipeline, so either should not make much difference, but I think it should suffice to mark this volatile to prevent any de-duplication of this load, and this should also be most conservative for GC but more liberal for other optimizations. Fixes #59547 Produced with dubious help by Claude. (cherry picked from commit 218f691)
KristofferC
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Sep 17, 2025
This is as an alternative to changing all allocation functions to mutating all memory and returning an aliasing pointer. This operates usually late in the pipeline, so either should not make much difference, but I think it should suffice to mark this volatile to prevent any de-duplication of this load, and this should also be most conservative for GC but more liberal for other optimizations. Fixes #59547 Produced with dubious help by Claude. (cherry picked from commit 218f691)
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KristofferC
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xal-0
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Sep 30, 2025
This is as an alternative to changing all allocation functions to mutating all memory and returning an aliasing pointer. This operates usually late in the pipeline, so either should not make much difference, but I think it should suffice to mark this volatile to prevent any de-duplication of this load, and this should also be most conservative for GC but more liberal for other optimizations. Fixes JuliaLang#59547 Produced with dubious help by Claude.
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This is as an alternative to changing all allocation functions to mutating all memory and returning an aliasing pointer. This operates usually late in the pipeline, so either should not make much difference, but I think it should suffice to mark this volatile to prevent any de-duplication of this load, and this should also be most conservative for GC but more liberal for other optimizations.
Fixes #59547
Produced with dubious help by Claude.