diff --git a/src/host/buildvm_lib.c b/src/host/buildvm_lib.c
index 8914251e..ffc1b2ca 100644
--- a/src/host/buildvm_lib.c
+++ b/src/host/buildvm_lib.c
@@ -378,7 +378,8 @@ void emit_lib(BuildCtx *ctx)
       char *p;
       /* Simplistic pre-processor. Only handles top-level #if/#endif. */
       if (buf[0] == '#' && buf[1] == 'i' && buf[2] == 'f') {
-	int ok = 1, len = strlen(buf);
+	int ok = 1;
+	size_t len = strlen(buf);
 	if (buf[len-1] == '\n') {
 	  buf[len-1] = 0;
 	  if (buf[len-2] == '\r') {
diff --git a/src/lj_opt_mem.c b/src/lj_opt_mem.c
index 455b0ca6..07dab0d9 100644
--- a/src/lj_opt_mem.c
+++ b/src/lj_opt_mem.c
@@ -229,8 +229,8 @@ static TRef fwd_ahload(jit_State *J, IRRef xref)
 	if (key->o == IR_KSLOT) key = IR(key->op1);
 	lj_ir_kvalue(J->L, &keyv, key);
 	tv = lj_tab_get(J->L, ir_ktab(IR(ir->op1)), &keyv);
-	lj_assertJ(itype2irt(tv) == irt_type(fins->t),
-		   "mismatched type in constant table");
+	if (itype2irt(tv) != irt_type(fins->t))
+	  return 0;  /* Type instability in loop-carried dependency. */
 	if (irt_isnum(fins->t))
 	  return lj_ir_knum_u64(J, tv->u64);
 	else if (LJ_DUALNUM && irt_isint(fins->t))