Improve SIMD casts * Allows `simd_cast` intrinsic to take `usize` and `isize` * Adds `simd_as` intrinsic, which is the same as `simd_cast` except for saturating float-to-int conversions (matching the behavior of `as`). cc `@workingjubilee`
in_band_lifetimes
rustc_codegen_llvm
Symbol
Ident
VariantDef
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