I'm doing some exploratory development for the original playstation with zig. Everything is fine in debug builds, but when turning on ReleaseSmall I get invalid instructions, specifically teq after a divu to check for divide by zero. teq isn't valid in the mips1 ISA and it's correctly recognized as such (I get a compile error if I try to use it as inline assembly).
I guess my question here really is is this a zig bug or an llvm bug, and how exactly can I narrow it down.
#target generating invalid instructions
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ok I think I found it, it's not a zig issue but llvm. the difference from zigs point of view was it was emitting one of those fancy mul by a large constant to do division by a constant, vs using the divu instruction. it does feel a bit weird that it's not the other way around though
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I'm doing some exploratory development for the original playstation with zig. E...
idk if you solved it already, but this sounds like you've got the wrong -cpu option
You gotta tell LLVM the CPU features you have available, as well as just the architecture
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the -cpu option is correct, it's a bug in llvm
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huh, weird
llvm is emitting that instruction despite it not being available with your cpu options?
that's very odd
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but fwiw mips1 support is considered "experimental"
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Might be worth reporting it to them if there's not already a bug for it
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already done 😎
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nice c:
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working on a fix, just gotta wait for llvm and zig to compile...