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Add is_const_eval intrinsic #959

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Add is_const_eval intrinsic #959

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3 changes: 3 additions & 0 deletions src/shims/intrinsics.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -223,6 +223,9 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
let discr_val = this.read_discriminant(place.into())?.0;
this.write_scalar(Scalar::from_uint(discr_val, dest.layout.size), dest)?;
}
"is_const_eval" => {
this.write_scalar(Scalar::from_u8(1), dest)?;
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This is correct from the what we can do perspective, but that means the naming of the intrinsic is wrong.

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Idk anything better though

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In C++ this is called is_constant_evaluated.

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Will this code even be executed? We usually prefer the librustc_mir implementation of an intrinsic, and only fall back here when none exists there.

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When I started working on this, I started here and not in rust-lang/rust because I thought that rust-lang/rust would call this library to evaluate the intrinsics. Now I am not sure if this makes sense.

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Ah I see. No, that's not how the code is organized. The code in this repo is only used by Miri-the-tool; rustc (and its test suite) to not use the code here at all.

}

"sinf32" | "fabsf32" | "cosf32" | "sqrtf32" | "expf32" | "exp2f32" | "logf32" |
"log10f32" | "log2f32" | "floorf32" | "ceilf32" | "truncf32" | "roundf32" => {
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