stage2: fix crash with comptime vector reduce

Author: andrewrk

src/value.zig

@@ -1194,6 +1194,16 @@ pub const Value = extern union {
         return switch (self.tag()) {
             .bool_true, .one => true,
             .bool_false, .zero => false,
+            .int_u64 => switch (self.castTag(.int_u64).?.data) {
+                0 => false,
+                1 => true,
+                else => unreachable,
+            },
+            .int_i64 => switch (self.castTag(.int_i64).?.data) {
+                0 => false,
+                1 => true,
+                else => unreachable,
+            },
             else => unreachable,
         };
     }

test/behavior/vector.zig

@@ -807,6 +807,16 @@ test "vector reduce operation" {
     comptime try S.doTheTest();
 }
 
+test "vector @reduce comptime" {
+    const value = @Vector(4, i32){ 1, -1, 1, -1 };
+    const result = value > @splat(4, @as(i32, 0));
+    // result is { true, false, true, false };
+    comptime try expect(@TypeOf(result) == @Vector(4, bool));
+    const is_all_true = @reduce(.And, result);
+    comptime try expect(@TypeOf(is_all_true) == bool);
+    try expect(is_all_true == false);
+}
+
 test "mask parameter of @shuffle is comptime scope" {
     if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
     if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO