[DSE] Delay deleting non-memory-defs until end of DSE. (#83411) #8323
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DSE uses BatchAA, which caches queries using pairs of MemoryLocations. At the moment, DSE may remove instructions that are used as pointers in cached MemoryLocations. If a new instruction used by a new MemoryLoation and this instruction gets allocated at the same address as a previosuly cached and then removed instruction, we may access an incorrect entry in the cache. To avoid this delay removing all instructions except MemoryDefs until the end of DSE. This should avoid removing any values used in BatchAA's cache. Test case by @vporpo from llvm#83181. (Test not precommitted because the results are non-determinstic - memset only sometimes gets removed) PR: llvm#83411
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@swift-ci please test |
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@swift-ci please test llvm |
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DSE uses BatchAA, which caches queries using pairs of MemoryLocations. At the moment, DSE may remove instructions that are used as pointers in cached MemoryLocations. If a new instruction used by a new MemoryLoation and this instruction gets allocated at the same address as a previosuly cached and then removed instruction, we may access an incorrect entry in the cache.
To avoid this delay removing all instructions except MemoryDefs until the end of DSE. This should avoid removing any values used in BatchAA's cache.
Test case by @vporpo from
llvm#83181.
(Test not precommitted because the results are non-determinstic - memset only sometimes gets removed)
PR: llvm#83411