llvm backend: llvm assert hit when compiling for mips and passing vector for f80 to a function

[antlilja]

Zig Version

0.11.0-dev.4059+17255bed4

Steps to Reproduce and Observed Behavior

The compiler hits an LLVM assert when passing a f80 vector to a function and compiling for mips

zig test test.zig -target mips64-linux-none (with a zig compiler linked to a debug version of LLVM)

// test.zig

fn foo(vec: @Vector(1, f80)) void {
    _ = vec;
}

test "test" {
    var x = foo(@Vector(1, f80){0.0});
    _ = x;
}

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp:767: getCopyToPartsVector: Assertion `Val.getValueType() == BuiltVectorTy && "Unexpected vector value type"' failed.

It seems to be and issue with LLVM itself and has already been reported in the LLVM issue tracker. But I thought it wouldn't hurt to file an issue if anyone else runs into it.

Expected Behavior

Does not crash

[andrewrk]

Thanks for reporting the issue upstream!

[tgross35]

Is this closed since llvm/llvm-project@e49103b was applied?

[Rexicon226]

Is this closed since llvm/llvm-project@e49103b was applied?

No, because this was applied to a version of LLVM that we haven't upgraded to yet. The error still happens in master branch.

[nektro]

that commit made it into llvm 17 so if it fixed the issue it would already be fixed on zig master. so it seems there's more investigating to be done.

[Rexicon226]

that commit made it into llvm 17 so if it fixed the issue it would already be fixed on zig master. so it seems there's more investigating to be done.

You're right, I missread the date of the commit 😄

The current error I'm getting on master is the same one antilja reported. However the reduced case reported in the LLVM issue passes for me now. So it seems there is another edge case here of some sort.

EDIT:
Sort of.

Running with build-exe causes the assertion, however building the IR with llc works fine.

[alexrp]

Still happens with LLVM 19:

/home/alexrp/Source/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp:811: void getCopyToPartsVector(llvm::SelectionDAG&, const llvm::SDLoc&, llvm::SDValue, llvm::SDValue*, unsigned int, llvm::MVT, const llvm::Value*, std::optional<unsigned int>): Assertion `Val.getValueType() == BuiltVectorTy && "Unexpected vector value type"' failed.