RFR: 8320682: [AArch64] C1 compilation fails with "Field too big for insn" [v3]

[Daniel Lundén]

On Fri, 8 Dec 2023 08:43:45 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> src/hotspot/share/c1/c1_globals.hpp line 280:
>> 
>>> 278:   develop(intx, NMethodSizeLimit, (64*K)*wordSize,                          \
>>> 279:           "Maximum size of a compiled method.")                             \
>>> 280:           range(0, 1*M)                                                     \
>> 
>> Shouldn't this be defined in platform-specific code, along with a comment explaining why 1MB was chosen?
>
> It could be, and I would have suggested doing so, but I am unaware of any circumstances in which ginormous C1-compiled methods are of any benefit to any port.

I think a 1MB upper bound is sensible for all platforms (see my other comment below). I'll add a comment explaining the choice, thanks. Please let me know if you think a larger bound is more suitable. In that case, we should also apply @theRealAph's improved aarch64 fix above for `const2reg`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16951#discussion_r1420482258