Integrated: 8299168: RISC-V: Fix MachNode size mismatch for MacroAssembler::_verify_oops*

[Xiaolin Zheng]

On Wed, 21 Dec 2022 04:47:51 GMT, Xiaolin Zheng <xlinzheng at openjdk.org> wrote:

> Nearly the same as [JDK-8285437](https://bugs.openjdk.org/browse/JDK-8285437). MachNode size should match in scratch emission and real emission phases. The address of the local char buffer is a random value, but when RVC is enabled, the `movptr`, containing `lui+addi+slli+addi+slli`, with another dangling `addi` at last to load the immediate address of the special local char buffer may get compressed depending on the char buffer's different addresses. So the size may at last mismatch. Due to this part containing implicit fixed-length semantics, it shall be a reasonable fix to add an `IncompressibleRegion` for these two special positions to disable automatic RVC transformations.
> 
> `test/hotspot/jtreg/testlibrary_tests/ir_framework/tests/TestDFlags.java` in hotspot tier4 can reflect this issue. It contains a `vm.flagless` so it didn't run in my local environment until recently.
> 
> Tested Hotspot tier1~4 with fastdebug build on physical hardware along with some other patches.
> 
> Thanks,
> Xiaolin

This pull request has now been integrated.

Changeset: 2f4098e1
Author:    Xiaolin Zheng <xlinzheng at openjdk.org>
Committer: Fei Yang <fyang at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/2f4098e1dc9c97e706d70008e473f9c4496cbc8a
Stats:     14 lines in 1 file changed: 6 ins; 0 del; 8 mod

8299168: RISC-V: Fix MachNode size mismatch for MacroAssembler::_verify_oops*

Reviewed-by: fyang

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PR: https://git.openjdk.org/jdk/pull/11750