Dedup some type checks in the MIR validator

1 files changed, 26 insertions, 0 deletions

diff --git a/compiler/rustc_const_eval/src/util/mod.rs b/compiler/rustc_const_eval/src/util/mod.rs
index 7641f560714..289e3422595 100644
--- a/compiler/rustc_const_eval/src/util/mod.rs
+++ b/compiler/rustc_const_eval/src/util/mod.rs
@@ -1,3 +1,5 @@
+use rustc_middle::mir;
+
 mod alignment;
 mod check_validity_requirement;
 mod compare_types;
@@ -7,3 +9,27 @@ pub use self::alignment::is_disaligned;
 pub use self::check_validity_requirement::check_validity_requirement;
 pub use self::compare_types::{is_equal_up_to_subtyping, is_subtype};
 pub use self::type_name::type_name;
+
+/// Classify whether an operator is "left-homogeneous", i.e., the LHS has the
+/// same type as the result.
+#[inline]
+pub(crate) fn binop_left_homogeneous(op: mir::BinOp) -> bool {
+    use rustc_middle::mir::BinOp::*;
+    match op {
+        Add | AddUnchecked | Sub | SubUnchecked | Mul | MulUnchecked | Div | Rem | BitXor
+        | BitAnd | BitOr | Offset | Shl | ShlUnchecked | Shr | ShrUnchecked => true,
+        Eq | Ne | Lt | Le | Gt | Ge => false,
+    }
+}
+
+/// Classify whether an operator is "right-homogeneous", i.e., the RHS has the
+/// same type as the LHS.
+#[inline]
+pub(crate) fn binop_right_homogeneous(op: mir::BinOp) -> bool {
+    use rustc_middle::mir::BinOp::*;
+    match op {
+        Add | AddUnchecked | Sub | SubUnchecked | Mul | MulUnchecked | Div | Rem | BitXor
+        | BitAnd | BitOr | Eq | Ne | Lt | Le | Gt | Ge => true,
+        Offset | Shl | ShlUnchecked | Shr | ShrUnchecked => false,
+    }
+}