SILCombine: don't sink forwarding instructions with address operands #86005
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We don't do memory lifetime analysis for this peephole optimization. Therefore we can't risk sinking instructions with address operands out of the addressed memory's lifetime. For example: ``` %3 = mark_dependence %2 on %1 : $*T // must not be moved after the destroy_addr destroy_addr %1 ``` Fixes a verifier crash rdar://166240751
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@swift-ci please test source compatibility release |
atrick
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Dec 12, 2025
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This is probably necessary just to quiet the memory verifier until it can recognize all the uses of dependent values as uses of the original address.
Ideally the verifier would not accept the incoming SIL:
%4 = mark_dependence %0 on %2
destroy_addr %2
destroy_value %4
It is illegal because it deinitializes a dependent value after deinitializing the value that it depends on.
What pass created the bad SIL pattern? And can we have a separate bug for that?
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We don't do memory lifetime analysis for this peephole optimization. Therefore we can't risk sinking instructions with address operands out of the addressed memory's lifetime.
For example:
Fixes a verifier crash
rdar://166240751