diff options
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/mir/place.rs | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/compiler/rustc_codegen_ssa/src/mir/place.rs b/compiler/rustc_codegen_ssa/src/mir/place.rs index b8fa8c0351b..c38484109d2 100644 --- a/compiler/rustc_codegen_ssa/src/mir/place.rs +++ b/compiler/rustc_codegen_ssa/src/mir/place.rs @@ -1,5 +1,6 @@ use rustc_abi::Primitive::{Int, Pointer}; -use rustc_abi::{Align, FieldsShape, Size, TagEncoding, VariantIdx, Variants}; +use rustc_abi::{Align, BackendRepr, FieldsShape, Size, TagEncoding, VariantIdx, Variants}; +use rustc_middle::mir::interpret::Scalar; use rustc_middle::mir::tcx::PlaceTy; use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, TyAndLayout}; use rustc_middle::ty::{self, Ty}; @@ -385,15 +386,22 @@ impl<'a, 'tcx, V: CodegenObject> PlaceRef<'tcx, V> { if variant_index != untagged_variant { let niche = self.project_field(bx, tag_field); let niche_llty = bx.cx().immediate_backend_type(niche.layout); + let BackendRepr::Scalar(scalar) = niche.layout.backend_repr else { + bug!("expected a scalar placeref for the niche"); + }; + // We are supposed to compute `niche_value.wrapping_add(niche_start)` wrapping + // around the `niche`'s type. + // The easiest way to do that is to do wrapping arithmetic on `u128` and then + // masking off any extra bits that occur because we did the arithmetic with too many bits. let niche_value = variant_index.as_u32() - niche_variants.start().as_u32(); let niche_value = (niche_value as u128).wrapping_add(niche_start); - // FIXME(eddyb): check the actual primitive type here. - let niche_llval = if niche_value == 0 { - // HACK(eddyb): using `c_null` as it works on all types. - bx.cx().const_null(niche_llty) - } else { - bx.cx().const_uint_big(niche_llty, niche_value) - }; + let niche_value = niche_value & niche.layout.size.unsigned_int_max(); + + let niche_llval = bx.cx().scalar_to_backend( + Scalar::from_uint(niche_value, niche.layout.size), + scalar, + niche_llty, + ); OperandValue::Immediate(niche_llval).store(bx, niche); } } |