diff --git a/qemu/tcg/optimize.c b/qemu/tcg/optimize.c
index 92db3b89..764cf26f 100644
--- a/qemu/tcg/optimize.c
+++ b/qemu/tcg/optimize.c
@@ -53,6 +53,26 @@ static void reset_temp(TCGContext *s, TCGArg temp)
     temps[temp].mask = -1;
 }
 
+/* Reset all temporaries, given that there are NB_TEMPS of them.  */
+static void reset_all_temps(TCGContext *s, int nb_temps)
+{
+    long len = BITS_TO_LONGS(nb_temps) * sizeof(unsigned long);
+    memset(&s->temps2_used.l, 0, len);
+}
+
+/* Initialize and activate a temporary.  */
+static void init_temp_info(TCGContext *s, TCGArg temp)
+{
+    struct tcg_temp_info *temps = s->temps2;
+    TCGTempSet *temps_used = &s->temps2_used;
+
+    if (!test_bit(temp, temps_used->l)) {
+        temps[temp].state = TCG_TEMP_UNDEF;
+        temps[temp].mask = -1;
+        set_bit(temp, temps_used->l);
+    }
+}
+
 static TCGOp *insert_op_before(TCGContext *s, TCGOp *old_op,
                                 TCGOpcode opc, int nargs)
 {
@@ -85,18 +105,6 @@ static TCGOp *insert_op_before(TCGContext *s, TCGOp *old_op,
     return new_op;
 }
 
-/* Reset all temporaries, given that there are NB_TEMPS of them.  */
-static void reset_all_temps(TCGContext *s, int nb_temps)
-{
-    struct tcg_temp_info *temps = s->temps2;
-    int i;
-
-    for (i = 0; i < nb_temps; i++) {
-        temps[i].state = TCG_TEMP_UNDEF;
-        temps[i].mask = -1;
-    }
-}
-
 static int op_bits(TCGContext *s, TCGOpcode op)
 {
     const TCGOpDef *def = &s->tcg_op_defs[op];
@@ -602,12 +610,24 @@ void tcg_optimize(TCGContext *s)
         const TCGOpDef *def = &s->tcg_op_defs[opc];
 
         oi_next = op->next;
+
+        /* Count the arguments, and initialize the temps that are
+           going to be used */
         if (opc == INDEX_op_call) {
             nb_oargs = op->callo;
             nb_iargs = op->calli;
+            for (i = 0; i < nb_oargs + nb_iargs; i++) {
+                tmp = args[i];
+                if (tmp != TCG_CALL_DUMMY_ARG) {
+                    init_temp_info(s, tmp);
+                }
+            }
         } else {
             nb_oargs = def->nb_oargs;
             nb_iargs = def->nb_iargs;
+            for (i = 0; i < nb_oargs + nb_iargs; i++) {
+                init_temp_info(s, args[i]);
+            }
         }
 
         /* Do copy propagation */
@@ -1303,7 +1323,9 @@ void tcg_optimize(TCGContext *s)
             if (!(args[nb_oargs + nb_iargs + 1]
                   & (TCG_CALL_NO_READ_GLOBALS | TCG_CALL_NO_WRITE_GLOBALS))) {
                 for (i = 0; i < nb_globals; i++) {
-                    reset_temp(s, i);
+                    if (test_bit(i, s->temps2_used.l)) {
+                        reset_temp(s, i);
+                    }
                 }
             }
             goto do_reset_output;
diff --git a/qemu/tcg/tcg.h b/qemu/tcg/tcg.h
index d86bb4f6..95b244bd 100644
--- a/qemu/tcg/tcg.h
+++ b/qemu/tcg/tcg.h
@@ -744,6 +744,7 @@ struct TCGContext {
 
     /* qemu/tcg/optimize.c */
     struct tcg_temp_info temps2[TCG_MAX_TEMPS];
+    TCGTempSet temps2_used;
 
     /* qemu/target-m68k/translate.c */
     TCGv_i32 cpu_halted;