RISC-V: "Illegal instruction" crash on SpacemiT-K3

[sxa]

Version

v26.5.0 (but any v26 and above is affected)

Platform

Linux firefly 6.18.3 #2 SMP PREEMPT_DYNAMIC Wed May 13 16:58:11 CST 2026 riscv64 GNU/Linux

Subsystem

V8

What steps will reproduce the bug?

run npm or any node-gyp on a SpacemiT-K3 board. Also fails in the build-addons step with make run-ci as that executes node-gyp. Other boards such as the SpacemiT-K1 do not show the crash (Both should have vector instructions available)

How often does it reproduce? Is there a required condition?

100% of the time

What is the expected behavior? Why is that the expected behavior?

There should be no crash when running npm

What do you see instead?

Illegal Instruction

Additional information

Based on the fact that sxa@1ecdd38 fixes it seems likely that this was introduced as part of the vector instructions introduced in v8/v8@de361fd - I haven't yet tracked it down to any specific operation in that function. At the moment I've also only determined that it fixes the initial crash and hopefully that doesn' uncover more issues.

FYI @luhenry @luyahan @nodejs/platform-riscv64

Split out from nodejs/build#4099 (comment)

[sxa]

That is likely not the only problem as even with that bypass of the vector instructions in that file enabled there are still Illegal instruction failures in some test cases e.g.

=== release test-http-set-global-proxy-from-env-fetch ===
Path: client-proxy/test-http-set-global-proxy-from-env-fetch
[CLOSE] null SIGILL
node:internal/modules/run_main:107
    triggerUncaughtException(
    ^