[CSKY] Don't emit __multi3 on 32-bit CSKY

[Dirreke]

Fix #68971
According to #21245 , disable __multi3 and other buitin functions which are not available in 32-bit target.

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[Dirreke]

@rengolin @DimitryAndric
Could you review it because it's similar to #21245 ?

[DimitryAndric]

This should be fine, but it needs a test, similar to llvm/test/CodeGen/ARM/umulo-128-legalisation-lowering.ll. (I don't know much about CSKY, but I assume that test case can mostly be copied except for the generated assembly code.)

[Dirreke]

This should be fine, but it needs a test, similar to llvm/test/CodeGen/ARM/umulo-128-legalisation-lowering.ll. (I don't know much about CSKY, but I assume that test case can mostly be copied except for the generated assembly code.)

Thanks! After some tests, I think #68971 is different from #21245 . I can not simply disable UINTTOFP_I128_FXX like __multi3 easily.

When program call the u128 related builtin functions like __multi3 and __floattidf on CSKY, the value of the parameters will be passed to the function, but the function will regard it as an address. It result a SIGSEGV.

I have no idea about how to fix it. Do you have any advice?

[Dirreke]

there's nothing to do. It's error in codegen of rust. Thank all of you2