3 files changed, 11 insertions, 6 deletions

diff --git a/c/c.h b/c/c.h
index 787db5d..45ce509 100644
--- a/c/c.h
+++ b/c/c.h
@@ -25,16 +25,18 @@ enum exprkind {
 struct expr {
    uchar t;
    uchar qual;
-   ushort narg; /* ECALL */
    union type ty;
    struct span span;
    union {
      struct {
-        struct expr *sub;
-        struct exgetfld {
-           ushort off;
-           uchar bitsiz, bitoff;
-        } fld; /* EGETF */
+        struct expr *sub; /* child(ren) */
+        union {
+           struct exgetfld {
+              ushort off;
+              uchar bitsiz, bitoff;
+           } fld; /* EGETF */
+           ushort narg; /* ECALL */
+        };
      };
      uvlong u; vlong i; double f; /* ENUMLIT */
      struct {
diff --git a/ir/ir.h b/ir/ir.h
index 6e8ae88..b47965d 100644
--- a/ir/ir.h
+++ b/ir/ir.h
@@ -68,6 +68,7 @@ union ref {
    struct { unsigned t : 3; signed i : 29; };
    uint bits;
 };
+static_assert(sizeof(union ref) == 4);
 
 struct addr {
    union ref base, index;
@@ -115,6 +116,7 @@ struct instr {
    uchar reg; /* 0 -> no reg; else reg + 1 */
    union ref l, r; /* args */
 };
+static_assert(sizeof(struct instr) == 4*3);
 
 enum jumpkind { JXXX, Jb, Jret, Jtrap, };
 
diff --git a/type.h b/type.h
index c3dffb7..6647e70 100644
--- a/type.h
+++ b/type.h
@@ -44,6 +44,7 @@ union type {
    };
    uint bits;
 };
+static_assert(sizeof(union type) == 4);
 
 #define isprimt(t)     in_range((t), TYBOOL, TYVOID)
 #define isintt(t)      in_range((t), TYENUM, TYUVLONG)