diff --git a/src/intrinsics/llvm_x86.rs b/src/intrinsics/llvm_x86.rs index 980d3262b67f..5b2b3ab2b62a 100644 --- a/src/intrinsics/llvm_x86.rs +++ b/src/intrinsics/llvm_x86.rs @@ -18,6 +18,20 @@ pub(crate) fn codegen_x86_llvm_intrinsic_call<'tcx>( // Spin loop hint } + // Used by is_x86_feature_detected!(); + "llvm.x86.xgetbv" => { + // FIXME use the actual xgetbv instruction + intrinsic_args!(fx, args => (v); intrinsic); + + let v = v.load_scalar(fx); + + // As of writing on XCR0 exists + fx.bcx.ins().trapnz(v, TrapCode::UnreachableCodeReached); + + let res = fx.bcx.ins().iconst(types::I64, 1 /* bit 0 must be set */); + ret.write_cvalue(fx, CValue::by_val(res, fx.layout_of(fx.tcx.types.i64))); + } + // Used by `_mm_movemask_epi8` and `_mm256_movemask_epi8` "llvm.x86.sse2.pmovmskb.128" | "llvm.x86.avx2.pmovmskb"