Method intcast

crates/rustc_codegen_spirv/src/builder/builder_methods.rs:1555–1610

(&mut self, val: Self::Value, dest_ty: Self::Type, is_signed: bool)

    }

    fn intcast(&mut self, val: Self::Value, dest_ty: Self::Type, is_signed: bool) -> Self::Value {
        if val.ty == dest_ty {
            // I guess?
            return val;
        }
        match (self.lookup_type(val.ty), self.lookup_type(dest_ty)) {
            // sign change
            (
                SpirvType::Integer(val_width, val_signedness),
                SpirvType::Integer(dest_width, dest_signedness),
            ) if val_width == dest_width && val_signedness != dest_signedness => self
                .emit()
                .bitcast(dest_ty, None, val.def(self))
                .unwrap()
                .with_type(dest_ty),
            // width change, and optional sign change
            (SpirvType::Integer(_, _), SpirvType::Integer(_, dest_signedness)) => {
                // spir-v spec doesn't seem to say that signedness needs to match the operands, only that the signedness
                // of the destination type must match the instruction's signedness.
                if dest_signedness {
                    self.emit().s_convert(dest_ty, None, val.def(self))
                } else {
                    self.emit().u_convert(dest_ty, None, val.def(self))
                }
                .unwrap()
                .with_type(dest_ty)
            }
            // bools are ints in llvm, so we have to implement this here
            (SpirvType::Bool, SpirvType::Integer(_, _)) => {
                // spir-v doesn't have a direct conversion instruction
                let if_true = self.constant_int(dest_ty, 1);
                let if_false = self.constant_int(dest_ty, 0);
                self.emit()
                    .select(
                        dest_ty,
                        None,
                        val.def(self),
                        if_true.def(self),
                        if_false.def(self),
                    )
                    .unwrap()
                    .with_type(dest_ty)
            }
            (SpirvType::Integer(_, _), SpirvType::Bool) => {
                // spir-v doesn't have a direct conversion instruction, glslang emits OpINotEqual
                let zero = self.constant_int(val.ty, 0);
                self.emit()
                    .i_not_equal(dest_ty, None, val.def(self), zero.def(self))
                    .unwrap()
                    .with_type(dest_ty)
            }
            (val_ty, dest_ty_spv) => self.fatal(&format!(
                "TODO: intcast not implemented yet: val={val:?} val.ty={val_ty:?} dest_ty={dest_ty_spv:?} is_signed={is_signed}"
            )),
        }
    }

    fn pointercast(&mut self, val: Self::Value, dest_ty: Self::Type) -> Self::Value {