stage2: implement comptime division

src/Module.zig

@@ -4585,6 +4585,37 @@ pub fn intSub(allocator: *Allocator, lhs: Value, rhs: Value) !Value {
     }
 }
 
+pub fn intDiv(allocator: *Allocator, lhs: Value, rhs: Value) !Value {
+    // TODO is this a performance issue? maybe we should try the operation without
+    // resorting to BigInt first.
+    var lhs_space: Value.BigIntSpace = undefined;
+    var rhs_space: Value.BigIntSpace = undefined;
+    const lhs_bigint = lhs.toBigInt(&lhs_space);
+    const rhs_bigint = rhs.toBigInt(&rhs_space);
+    const limbs_q = try allocator.alloc(
+        std.math.big.Limb,
+        lhs_bigint.limbs.len + rhs_bigint.limbs.len + 1,
+    );
+    const limbs_r = try allocator.alloc(
+        std.math.big.Limb,
+        lhs_bigint.limbs.len,
+    );
+    const limbs_buffer = try allocator.alloc(
+        std.math.big.Limb,
+        std.math.big.int.calcDivLimbsBufferLen(lhs_bigint.limbs.len, rhs_bigint.limbs.len),
+    );
+    var result_q = BigIntMutable{ .limbs = limbs_q, .positive = undefined, .len = undefined };
+    var result_r = BigIntMutable{ .limbs = limbs_r, .positive = undefined, .len = undefined };
+    result_q.divTrunc(&result_r, lhs_bigint, rhs_bigint, limbs_buffer, null);
+    const result_limbs = result_q.limbs[0..result_q.len];
+
+    if (result_q.positive) {
+        return Value.Tag.int_big_positive.create(allocator, result_limbs);
+    } else {
+        return Value.Tag.int_big_negative.create(allocator, result_limbs);
+    }
+}
+
 pub fn floatAdd(
     arena: *Allocator,
     float_type: Type,
@@ -4651,6 +4682,39 @@ pub fn floatSub(
     }
 }
 
+pub fn floatDiv(
+    arena: *Allocator,
+    float_type: Type,
+    src: LazySrcLoc,
+    lhs: Value,
+    rhs: Value,
+) !Value {
+    switch (float_type.tag()) {
+        .f16 => {
+            @panic("TODO add __trunctfhf2 to compiler-rt");
+            //const lhs_val = lhs.toFloat(f16);
+            //const rhs_val = rhs.toFloat(f16);
+            //return Value.Tag.float_16.create(arena, lhs_val / rhs_val);
+        },
+        .f32 => {
+            const lhs_val = lhs.toFloat(f32);
+            const rhs_val = rhs.toFloat(f32);
+            return Value.Tag.float_32.create(arena, lhs_val / rhs_val);
+        },
+        .f64 => {
+            const lhs_val = lhs.toFloat(f64);
+            const rhs_val = rhs.toFloat(f64);
+            return Value.Tag.float_64.create(arena, lhs_val / rhs_val);
+        },
+        .f128, .comptime_float, .c_longdouble => {
+            const lhs_val = lhs.toFloat(f128);
+            const rhs_val = rhs.toFloat(f128);
+            return Value.Tag.float_128.create(arena, lhs_val / rhs_val);
+        },
+        else => unreachable,
+    }
+}
+
 pub fn simplePtrType(
     mod: *Module,
     arena: *Allocator,

src/Sema.zig

@@ -4139,6 +4139,13 @@ fn analyzeArithmetic(
                         try Module.floatSub(sema.arena, scalar_type, src, lhs_val, rhs_val);
                     break :blk val;
                 },
+                .div => blk: {
+                    const val = if (is_int)
+                        try Module.intDiv(sema.arena, lhs_val, rhs_val)
+                    else
+                        try Module.floatDiv(sema.arena, scalar_type, src, lhs_val, rhs_val);
+                    break :blk val;
+                },
                 else => return sema.mod.fail(&block.base, src, "TODO Implement arithmetic operand '{s}'", .{@tagName(zir_tag)}),
             };