RFR: 8259609: C2: optimize long range checks in long counted loops

[Tobias Hartmann]

On Mon, 18 Jan 2021 13:34:16 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> I think you forgot to push the fix.
>
>> I think you forgot to push the fix.
> 
> Indeed. Pushed now.

I'm now seeing this with the same test at a higher tier (and therefore different flags):
#  Internal Error (workspace/open/src/hotspot/share/opto/loopPredicate.cpp:1154), pid=8709, tid=8726
#  assert(ok) failed: must be index expression

Stack: [0x00007f2f3bdfe000,0x00007f2f3beff000],  sp=0x00007f2f3bef8fd0,  free space=1003k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
V  [libjvm.so+0x129032b]  PhaseIdealLoop::loop_predication_impl_helper(IdealLoopTree*, ProjNode*, ProjNode*, CountedLoopNode*, ConNode*, Invariance&, Deoptimization::DeoptReason)+0x74b
V  [libjvm.so+0x1291e0b]  PhaseIdealLoop::loop_predication_impl(IdealLoopTree*) [clone .part.0]+0x81b
V  [libjvm.so+0x1292d09]  IdealLoopTree::loop_predication(PhaseIdealLoop*)+0x109
V  [libjvm.so+0x1292c28]  IdealLoopTree::loop_predication(PhaseIdealLoop*)+0x28
V  [libjvm.so+0x12dd182]  PhaseIdealLoop::build_and_optimize(LoopOptsMode)+0x1282
V  [libjvm.so+0xa1bfbb]  PhaseIdealLoop::optimize(PhaseIterGVN&, LoopOptsMode)+0x32b
V  [libjvm.so+0xa182a6]  Compile::Optimize()+0x586
V  [libjvm.so+0xa1af60]  Compile::Compile(ciEnv*, ciMethod*, int, bool, bool, bool, bool, DirectiveSet*)+0x1840
V  [libjvm.so+0x84a6bc]  C2Compiler::compile_method(ciEnv*, ciMethod*, int, bool, DirectiveSet*)+0x1dc
V  [libjvm.so+0xa2afd8]  CompileBroker::invoke_compiler_on_method(CompileTask*)+0xe88
V  [libjvm.so+0xa2bc28]  CompileBroker::compiler_thread_loop()+0x5a8
V  [libjvm.so+0x1856b66]  JavaThread::thread_main_inner()+0x256
V  [libjvm.so+0x185d570]  Thread::call_run()+0x100
V  [libjvm.so+0x1543f46]  thread_native_entry(Thread*)+0x116

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PR: https://git.openjdk.java.net/jdk/pull/2045