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  1. JDK
  2. JDK-8209420

Track membars for volatile accesses so they can be properly optimized

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      Description

        Aarch64 emits a single instruction for volatile accesses that include the required memory barriers. For this to work properly the aarch64 backend has to locate membars that go with a memory access to elide them. This is currently implemented with some complicated pattern matching that has proven fragile and painful to maintain. This change introduces a new and robust logic to locate membars and memory accesses for volatile accesses.

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            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8230198 Track membars for volatile accesses so they can be properly optimized

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8243344 Track membars for volatile accesses so they can be properly optimized

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8260820 Track membars for volatile accesses so they can be properly optimized

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved

            Backport - A issue that is required to port a Bug or Feature into another product release. This issue type is generally associated with the main Bug/Feature to represent each individual release of the port. JDK-8261726 Track membars for volatile accesses so they can be properly optimized

            • P4 - Minor loss of function, or other problem where easy workaround is present.
            • Resolved
            blocks

            Bug - A problem which impairs or prevents the functions of the product. JDK-8210389 C2: assert(n->outcnt() != 0 || C->top() == n || n->is_Proj()) failed: No dead instructions after post-alloc

            • P3 - Major loss of function.
            • Resolved
            relates to

            Bug - A problem which impairs or prevents the functions of the product. JDK-8211233 MemBarNode::trailing_membar() and MemBarNode::leading_membar() need to handle dying subgraphs better

            • P3 - Major loss of function.
            • Resolved

            Bug - A problem which impairs or prevents the functions of the product. JDK-8214857 "bad trailing membar" assert failure at memnode.cpp:3220

            • P3 - Major loss of function.
            • Resolved

            Enhancement - null JDK-8257192 Integrate AArch64 JIT port into 8u

            • P3 - Major loss of function.
            • Resolved

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                roland Roland Westrelin
                roland Roland Westrelin
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