[8u] RFR: 8233023: assert(Opcode() == mem->Opcode() || phase->C->get_alias_index(adr_type()) == Compile::AliasIdxRaw) failed: no mismatched stores, except on raw memory

[Severin Gehwolf]

Hi,

Could I please get a review of this 8u only issue? The reason a
fastdebug build of latest OpenJDK 8u asserts for the dec-tree benchmark
of the renaissance suite is because the 8u backport of JDK-8140309 was
missing this hunk from JDK 9[1]:

+             (Opcode() == Op_StoreL && st->Opcode() == Op_StoreI) || // expanded ClearArrayNode
+             (is_mismatched_access() || st->as_Store()->is_mismatched_access()),

I had a closer look and there doesn't seem to be missing anything else.
The proposed fix is to amend the assert condition in the appropriate
place, which brings 8u in line with JDK 9 code where the failure isn't
observed.

Bug: https://bugs.openjdk.java.net/browse/JDK-8233023
webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8233023/01/webrev/

Testing: 8u tier1 test set with fastdebug build on x86_64 Linux. No new
failures. dec-tree benchmark now runs successfully on an 8u fastdebug
build.

Thoughts?

Thanks,
Severin

[1] http://hg.openjdk.java.net/jdk9/jdk9/hotspot/rev/4bee38ba018c