Add support for operators on Core.IntLiteral.

core/io.carbon

@@ -15,5 +15,4 @@ fn PrintChar(x: i32) -> i32 = "print.char";
 fn ReadChar() -> i32 = "read.char";
 
 // TODO: Change this to a global constant once they are fully supported.
-// TODO: Use simply -1 once we support negate on an IntLiteral.
-fn EOF() -> i32 { return -(1 as i32); }
+fn EOF() -> i32 { return -1; }

core/prelude/operators/arithmetic.carbon

@@ -4,6 +4,8 @@
 
 package Core library "prelude/operators/arithmetic";
 
+import library "prelude/types/int_literal";
+
 // Addition: `a + b`.
 interface Add {
   fn Op[self: Self](other: Self) -> Self;
@@ -68,3 +70,30 @@ interface Mod {
 interface ModAssign {
   fn Op[addr self: Self*](other: Self);
 }
+
+
+// Operations for IntLiteral. These need to be here because IntLiteral has no
+// associated library of its own.
+impl IntLiteral() as Add {
+  fn Op[self: Self](other: Self) -> Self = "int.sadd";
+}
+
+impl IntLiteral() as Div {
+  fn Op[self: Self](other: Self) -> Self = "int.sdiv";
+}
+
+impl IntLiteral() as Mod {
+  fn Op[self: Self](other: Self) -> Self = "int.smod";
+}
+
+impl IntLiteral() as Mul {
+  fn Op[self: Self](other: Self) -> Self = "int.smul";
+}
+
+impl IntLiteral() as Negate {
+  fn Op[self: Self]() -> Self = "int.snegate";
+}
+
+impl IntLiteral() as Sub {
+  fn Op[self: Self](other: Self) -> Self = "int.ssub";
+}

core/prelude/operators/bitwise.carbon

@@ -4,6 +4,8 @@
 
 package Core library "prelude/operators/bitwise";
 
+import library "prelude/types/int_literal";
+
 // Bit complement: `^a`.
 interface BitComplement {
   fn Op[self: Self]() -> Self;
@@ -58,3 +60,30 @@ interface RightShift {
 interface RightShiftAssign {
   fn Op[addr self: Self*](other: Self);
 }
+
+
+// Operations for IntLiteral. These need to be here because IntLiteral has no
+// associated library of its own.
+impl IntLiteral() as BitAnd {
+  fn Op[self: Self](other: Self) -> Self = "int.and";
+}
+
+impl IntLiteral() as BitComplement {
+  fn Op[self: Self]() -> Self = "int.complement";
+}
+
+impl IntLiteral() as BitOr {
+  fn Op[self: Self](other: Self) -> Self = "int.or";
+}
+
+impl IntLiteral() as BitXor {
+  fn Op[self: Self](other: Self) -> Self = "int.xor";
+}
+
+impl IntLiteral() as LeftShift {
+  fn Op[self: Self](other: Self) -> Self = "int.left_shift";
+}
+
+impl IntLiteral() as RightShift {
+  fn Op[self: Self](other: Self) -> Self = "int.right_shift";
+}

core/prelude/operators/comparison.carbon

@@ -5,6 +5,7 @@
 package Core library "prelude/operators/comparison";
 
 export import library "prelude/types/bool";
+import library "prelude/types/int_literal";
 
 // Equality comparison: `a == b` and `a != b`.
 interface Eq {
@@ -28,3 +29,19 @@ impl bool as Eq {
   fn Equal[self: Self](other: Self) -> bool = "bool.eq";
   fn NotEqual[self: Self](other: Self) -> bool = "bool.neq";
 }
+
+
+// Operations for IntLiteral. These need to be here because IntLiteral has no
+// associated library of its own.
+impl IntLiteral() as Eq {
+  fn Equal[self: Self](other: Self) -> bool = "int.eq";
+  fn NotEqual[self: Self](other: Self) -> bool = "int.neq";
+}
+
+impl IntLiteral() as Ordered {
+  // TODO: fn Compare
+  fn Less[self: Self](other: Self) -> bool = "int.less";
+  fn LessOrEquivalent[self: Self](other: Self) -> bool = "int.less_eq";
+  fn Greater[self: Self](other: Self) -> bool = "int.greater";
+  fn GreaterOrEquivalent[self: Self](other: Self) -> bool = "int.greater_eq";
+}

toolchain/base/int.h

@@ -232,6 +232,14 @@ constexpr int32_t IntId::InvalidIndex = Invalid.AsIndex();
 // an array of `APInt` values and represented as an index in the ID.
 class IntStore {
  public:
+  // The maximum supported bit width of an integer type.
+  // TODO: Pick a maximum size and document it in the design. For now
+  // we use 2^^23, because that's the largest size that LLVM supports.
+  static constexpr int MaxIntWidth = 1 << 23;
+
+  // Pick a canonical bit width for the provided number of significant bits.
+  static auto CanonicalBitWidth(int significant_bits) -> int;
+
   // Accepts a signed `int64_t` and uses the mathematical signed integer value
   // of it as the added integer value.
   //
@@ -395,9 +403,6 @@ class IntStore {
     return IntId::Invalid;
   }
 
-  // Pick a canonical bit width for the provided number of significant bits.
-  static auto CanonicalBitWidth(int significant_bits) -> int;
-
   // Canonicalize an incoming signed APInt to the correct bit width.
   static auto CanonicalizeSigned(llvm::APInt value) -> llvm::APInt;