Fix sequentialStoreSimplifier for OffHeap #20826
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SequentialStoreSimplifier checks the baseVariable symRef to confirm compatibility. With OffHeap baseVariable used is the dataAddrPtr which would match symRefs even for different arrays. This commit compares the dataAddrPtr child symRef for compatibility.
| baseNode = baseNode->getFirstChild(); | ||
| activeBaseRef = baseNode->getSymbolReference(); | ||
| } | ||
| else | ||
| { |
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do you need to compare every step of getting active/base ref? currently, you only compare the end results, ignoring if the middle-step(s) are consistent as well. i.e. can there be a situation where one of the refs is gotten without going through dataAddr node ... tree shapes are different, but ref(s) are the same?
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The method generateArraycopyFromSequentialStores is called for a store and it does checks (the store node, the value node, the dest node) for subsequent trees for valid candidates, and I'm changing where it checks the base address symRef in the dest node check. One other shape that's introduced with OffHeap is if its accessing the first element in an array where there's no aladd. Other modifications needed to handle that.
arr[0]
n60n aloadi <contiguousArrayDataAddrField>[#373 final Shadow +8] [flags 0x20604 0x0 ] (internalPtr ) [0x767885060280] bci=[-1,46,2542] rc=1 vc=426 vn=- li=- udi=- nc=1 flg=0x80>
n11n ==>newarray
vs
arr[1] // byte-array
n62n aladd (X>=0 internalPtr ) [0x767885060320] bci=[-1,46,2542] rc=2 vc=426 vn=- li=- udi=- nc=2 flg=0x8100
n60n aloadi <contiguousArrayDataAddrField>[#373 final Shadow +8] [flags 0x20604 0x0 ] (internalPtr ) [0x767885060280] bci=[-1,46,2542] rc=1 vc=426 vn=- li=- udi=- nc=1 flg=0x80>
n11n ==>newarray
n61n lconst 1 (highWordZero X!=0 X>=0 ) [0x7678850602d0] bci=[-1,46,2542] rc=1 vc=426 vn=- li=- udi=- nc=0 flg=0x4104
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Closing issue, moving fixes to:
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SequentialStoreSimplifier checks the baseVariable symRef to confirm compatibility. With OffHeap baseVariable used is the dataAddrPtr which would match symRefs even for different arrays.
This fix compares the dataAddrPtr child symRefs for compatibility.