Legalize: make the feature set comptime-known in zig1

This allows legalizations to be added that aren't used by zig1 without
affecting the size of zig1.

1 files changed, 13 insertions, 6 deletions

diff --git a/src/codegen/c.zig b/src/codegen/c.zig
index f4952d4a58..0fe3f80919 100644
--- a/src/codegen/c.zig
+++ b/src/codegen/c.zig
@@ -23,12 +23,19 @@ const BigIntLimb = std.math.big.Limb;
 const BigInt = std.math.big.int;
 
 pub fn legalizeFeatures(_: *const std.Target) ?*const Air.Legalize.Features {
-    return if (dev.env.supports(.legalize)) comptime &.initMany(&.{
-        .expand_intcast_safe,
-        .expand_add_safe,
-        .expand_sub_safe,
-        .expand_mul_safe,
-    }) else null; // we don't currently ask zig1 to use safe optimization modes
+    return comptime switch (dev.env.supports(.legalize)) {
+        inline false, true => |supports_legalize| &.init(.{
+            // we don't currently ask zig1 to use safe optimization modes
+            .expand_intcast_safe = supports_legalize,
+            .expand_add_safe = supports_legalize,
+            .expand_sub_safe = supports_legalize,
+            .expand_mul_safe = supports_legalize,
+
+            .expand_packed_load = true,
+            .expand_packed_store = true,
+            .expand_packed_struct_field_val = true,
+        }),
+    };
 }
 
 /// For most backends, MIR is basically a sequence of machine code instructions, perhaps with some