RFR: 8375046: C2: Assertion failed in GrowableArray::remove_till(0)

[Aleksey Shipilev]

On Mon, 12 Jan 2026 15:33:28 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Seen this assert in stress CTW runs:
> 
> 
> # Internal Error (/home/shade/trunks/jdk/src/hotspot/share/utilities/growableArray.hpp:498), pid=2972347, tid=2973775
> # assert(start < end && end <= this->_len) failed: erase called with invalid range (0, 0) for length 0
> 
> Stack: [0x00007fd660bea000,0x00007fd660cea000], sp=0x00007fd660ce4fc0, free space=1003k
> Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
> V [libjvm.so+0xc00a41] Compile::inline_incrementally_one()+0x801 (growableArray.hpp:498)
> V [libjvm.so+0xc01650] Compile::inline_incrementally(PhaseIterGVN&)+0x2f0 (compile.cpp:2212)
> V [libjvm.so+0xc04581] Compile::Optimize()+0x7d1 (compile.cpp:2357) 
> 
> 
> It looks innocuous, as `GrowableArray::remove_range` does nothing real on `[0, 0)`. It is still IMO a bug to call it with `[0, 0)`, as it is not clear whether to trust inclusive or exclusive boundary. But for `remove_till`, it looks plausible that `remove_till(0)` should work and be a no-op.
> 
> Additional testing:
>  - [x] Linux x86_64 server fastdebug, new gtest used to fail without the fix, now passes

Oh, `GrowableArray::remove_till` is also used in G1, dang. For clarity, I think we can just use `remove_range` then and only handle this on C2 side. Let me do that...

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PR Comment: https://git.openjdk.org/jdk/pull/29171#issuecomment-3739197443