Promote unchecked_add/sub/mul/shl/shr to mir::BinOp

2 files changed, 29 insertions, 2 deletions

diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs
index 1a65f74f4fe..ddc9fdc9a42 100644
--- a/compiler/rustc_middle/src/mir/syntax.rs
+++ b/compiler/rustc_middle/src/mir/syntax.rs
@@ -1267,10 +1267,16 @@ pub enum UnOp {
 pub enum BinOp {
     /// The `+` operator (addition)
     Add,
+    /// Like `Add`, but with UB on overflow.  (Integers only.)
+    AddUnchecked,
     /// The `-` operator (subtraction)
     Sub,
+    /// Like `Sub`, but with UB on overflow.  (Integers only.)
+    SubUnchecked,
     /// The `*` operator (multiplication)
     Mul,
+    /// Like `Mul`, but with UB on overflow.  (Integers only.)
+    MulUnchecked,
     /// The `/` operator (division)
     ///
     /// For integer types, division by zero is UB, as is `MIN / -1` for signed.
@@ -1296,10 +1302,17 @@ pub enum BinOp {
     ///
     /// The offset is truncated to the size of the first operand before shifting.
     Shl,
+    /// Like `Shl`, but is UB if the RHS >= LHS::BITS
+    ShlUnchecked,
     /// The `>>` operator (shift right)
     ///
     /// The offset is truncated to the size of the first operand before shifting.
+    ///
+    /// This is an arithmetic shift if the LHS is signed
+    /// and a logical shift if the LHS is unsigned.
     Shr,
+    /// Like `Shl`, but is UB if the RHS >= LHS::BITS
+    ShrUnchecked,
     /// The `==` operator (equality)
     Eq,
     /// The `<` operator (less than)
diff --git a/compiler/rustc_middle/src/mir/tcx.rs b/compiler/rustc_middle/src/mir/tcx.rs
index 5ca82413448..4a16abdd4e3 100644
--- a/compiler/rustc_middle/src/mir/tcx.rs
+++ b/compiler/rustc_middle/src/mir/tcx.rs
@@ -235,8 +235,11 @@ impl<'tcx> BinOp {
         // FIXME: handle SIMD correctly
         match self {
             &BinOp::Add
+            | &BinOp::AddUnchecked
             | &BinOp::Sub
+            | &BinOp::SubUnchecked
             | &BinOp::Mul
+            | &BinOp::MulUnchecked
             | &BinOp::Div
             | &BinOp::Rem
             | &BinOp::BitXor
@@ -246,7 +249,11 @@ impl<'tcx> BinOp {
                 assert_eq!(lhs_ty, rhs_ty);
                 lhs_ty
             }
-            &BinOp::Shl | &BinOp::Shr | &BinOp::Offset => {
+            &BinOp::Shl
+            | &BinOp::ShlUnchecked
+            | &BinOp::Shr
+            | &BinOp::ShrUnchecked
+            | &BinOp::Offset => {
                 lhs_ty // lhs_ty can be != rhs_ty
             }
             &BinOp::Eq | &BinOp::Lt | &BinOp::Le | &BinOp::Ne | &BinOp::Ge | &BinOp::Gt => {
@@ -293,7 +300,14 @@ impl BinOp {
             BinOp::Gt => hir::BinOpKind::Gt,
             BinOp::Le => hir::BinOpKind::Le,
             BinOp::Ge => hir::BinOpKind::Ge,
-            BinOp::Offset => unreachable!(),
+            BinOp::AddUnchecked
+            | BinOp::SubUnchecked
+            | BinOp::MulUnchecked
+            | BinOp::ShlUnchecked
+            | BinOp::ShrUnchecked
+            | BinOp::Offset => {
+                unreachable!()
+            }
         }
     }
 }