use crate::va_arg::emit_va_arg;
use crate::value::Value;
+use rustc_ast as ast;
use rustc_codegen_ssa::base::{compare_simd_types, wants_msvc_seh};
use rustc_codegen_ssa::common::span_invalid_monomorphization_error;
use rustc_codegen_ssa::common::{IntPredicate, TypeKind};
}
}
+ sym::black_box => {
+ args[0].val.store(self, result);
+
+ // We need to "use" the argument in some way LLVM can't introspect, and on
+ // targets that support it we can typically leverage inline assembly to do
+ // this. LLVM's interpretation of inline assembly is that it's, well, a black
+ // box. This isn't the greatest implementation since it probably deoptimizes
+ // more than we want, but it's so far good enough.
+ crate::asm::inline_asm_call(
+ self,
+ "",
+ "r,~{memory}",
+ &[result.llval],
+ self.type_void(),
+ true,
+ false,
+ ast::LlvmAsmDialect::Att,
+ &[span],
+ )
+ .unwrap_or_else(|| bug!("failed to generate inline asm call for `black_box`"));
+
+ // We have copied the value to `result` already.
+ return;
+ }
+
_ if name_str.starts_with("simd_") => {
match generic_simd_intrinsic(self, name, callee_ty, args, ret_ty, llret_ty, span) {
Ok(llval) => llval,