1 files changed, 6 insertions, 6 deletions

diff --git a/src/lj_parse.c b/src/lj_parse.c
index 5a8bcff9..57eb11cc 100644
--- a/src/lj_parse.c
+++ b/src/lj_parse.c
@@ -951,22 +951,22 @@ static void bcemit_unop(FuncState *fs, BCOp op, ExpDesc *e)
 #if LJ_HASFFI
       if (e->k == VKCDATA) {  /* Fold in-place since cdata is not interned. */
         GCcdata *cd = cdataV(&e->u.nval);
-        int64_t *p = (int64_t *)cdataptr(cd);
+        uint64_t *p = (uint64_t *)cdataptr(cd);
         if (cd->ctypeid == CTID_COMPLEX_DOUBLE)
-          p[1] ^= (int64_t)U64x(80000000,00000000);
+          p[1] ^= U64x(80000000,00000000);
         else
-          *p = -*p;
+          *p = ~*p+1u;
         return;
       } else
 #endif
       if (expr_isnumk(e) && !expr_numiszero(e)) {  /* Avoid folding to -0. */
         TValue *o = expr_numtv(e);
         if (tvisint(o)) {
-          int32_t k = intV(o);
-          if (k == -k)
+          int32_t k = intV(o), negk = (int32_t)(~(uint32_t)k+1u);
+          if (k == negk)
             setnumV(o, -(lua_Number)k);
           else
-            setintV(o, -k);
+            setintV(o, negk);
           return;
         } else {
           o->u64 ^= U64x(80000000,00000000);