stage2: more arithmetic support

 * AIR: add `mod` instruction for modulus division
   - Implement for LLVM backend
 * Sema: implement `@mod`, `@rem`, and `%`.
 * Sema: fix comptime switch evaluation
 * Sema: implement comptime shift left
 * Sema: fix the logic inside analyzeArithmetic to handle all the
   nuances between the different mathematical operations.
   - Implement comptime wrapping operations

1 files changed, 9 insertions, 2 deletions

diff --git a/src/Air.zig b/src/Air.zig
index b4552f9d7b..b5d19127a0 100644
--- a/src/Air.zig
+++ b/src/Air.zig
@@ -69,10 +69,16 @@ pub const Inst = struct {
         /// is the same as both operands.
         /// Uses the `bin_op` field.
         div,
-        /// Integer or float remainder.
-        /// Both operands are guaranteed to be the same type, and the result type is the same as both operands.
+        /// Integer or float remainder division.
+        /// Both operands are guaranteed to be the same type, and the result type
+        /// is the same as both operands.
         /// Uses the `bin_op` field.
         rem,
+        /// Integer or float modulus division.
+        /// Both operands are guaranteed to be the same type, and the result type
+        /// is the same as both operands.
+        /// Uses the `bin_op` field.
+        mod,
         /// Add an offset to a pointer, returning a new pointer.
         /// The offset is in element type units, not bytes.
         /// Wrapping is undefined behavior.
@@ -568,6 +574,7 @@ pub fn typeOfIndex(air: Air, inst: Air.Inst.Index) Type {
         .mulwrap,
         .div,
         .rem,
+        .mod,
         .bit_and,
         .bit_or,
         .xor,