diff options
Diffstat (limited to 'compiler/rustc_const_eval/src/const_eval/machine.rs')
| -rw-r--r-- | compiler/rustc_const_eval/src/const_eval/machine.rs | 18 |
1 files changed, 5 insertions, 13 deletions
diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs index f24fb18f83b..a18ae79f318 100644 --- a/compiler/rustc_const_eval/src/const_eval/machine.rs +++ b/compiler/rustc_const_eval/src/const_eval/machine.rs @@ -279,23 +279,15 @@ impl<'tcx> CompileTimeInterpCx<'tcx> { fn guaranteed_cmp(&mut self, a: Scalar, b: Scalar) -> InterpResult<'tcx, u8> { interp_ok(match (a, b) { // Comparisons between integers are always known. - (Scalar::Int { .. }, Scalar::Int { .. }) => { - if a == b { - 1 - } else { - 0 - } - } - // Comparisons of abstract pointers with null pointers are known if the pointer - // is in bounds, because if they are in bounds, the pointer can't be null. - // Inequality with integers other than null can never be known for sure. - (Scalar::Int(int), ptr @ Scalar::Ptr(..)) - | (ptr @ Scalar::Ptr(..), Scalar::Int(int)) + (Scalar::Int(a), Scalar::Int(b)) => (a == b) as u8, + // Comparisons of null with an arbitrary scalar can be known if `scalar_may_be_null` + // indicates that the scalar can definitely *not* be null. + (Scalar::Int(int), ptr) | (ptr, Scalar::Int(int)) if int.is_null() && !self.scalar_may_be_null(ptr)? => { 0 } - // Equality with integers can never be known for sure. + // Other ways of comparing integers and pointers can never be known for sure. (Scalar::Int { .. }, Scalar::Ptr(..)) | (Scalar::Ptr(..), Scalar::Int { .. }) => 2, // FIXME: return a `1` for when both sides are the same pointer, *except* that // some things (like functions and vtables) do not have stable addresses |