1d8d25777d
The normal dataflow sequence in the ARC optimizer consists of the following states: Retain -> CanRelease -> Use -> Release The optimizer before this patch stored the uses that determine the lifetime of the retainable object pointer when it bottom up hits a retain or when top down it hits a release. This is correct for an imprecise lifetime scenario since what we are trying to do is remove retains/releases while making sure that no ``CanRelease'' (which is usually a call) deallocates the given pointer before we get to the ``Use'' (since that would cause a segfault). If we are considering the precise lifetime scenario though, this is not correct. In such a situation, we *DO* care about the previous sequence, but additionally, we wish to track the uses resulting from the following incomplete sequences: Retain -> CanRelease -> Release (TopDown) Retain <- Use <- Release (BottomUp) *NOTE* This patch looks large but the most of it consists of updating test cases. Additionally this fix exposed an additional bug. I removed the test case that expressed said bug and will recommit it with the fix in a little bit. llvm-svn: 178921 |
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clang | ||
clang-tools-extra | ||
compiler-rt | ||
debuginfo-tests | ||
libclc | ||
libcxx | ||
libcxxabi | ||
lld | ||
lldb | ||
llvm | ||
polly |