diff --git a/def-helper.h b/def-helper.h
index 8a88c5b..8a822c7 100644
--- a/def-helper.h
+++ b/def-helper.h
@@ -81,9 +81,29 @@
 #define dh_is_64bit_ptr (TCG_TARGET_REG_BITS == 64)
 #define dh_is_64bit(t) glue(dh_is_64bit_, dh_alias(t))
 
+#define dh_is_signed_void 0
+#define dh_is_signed_i32 0
+#define dh_is_signed_s32 1
+#define dh_is_signed_i64 0
+#define dh_is_signed_s64 1
+#define dh_is_signed_f32 0
+#define dh_is_signed_f64 0
+#define dh_is_signed_tl  0
+#define dh_is_signed_int 1
+/* ??? This is highly specific to the host cpu.  There are even special
+   extension instructions that may be required, e.g. ia64's addp4.  But
+   for now we don't support any 64-bit targets with 32-bit pointers.  */
+#define dh_is_signed_ptr 0
+#define dh_is_signed_env dh_is_signed_ptr
+#define dh_is_signed(t) dh_is_signed_##t
+
+#define dh_sizemask(t, n) \
+  sizemask |= dh_is_64bit(t) << (n*2); \
+  sizemask |= dh_is_signed(t) << (n*2+1)
+
 #define dh_arg(t, n) \
   args[n - 1] = glue(GET_TCGV_, dh_alias(t))(glue(arg, n)); \
-  sizemask |= dh_is_64bit(t) << n
+  dh_sizemask(t, n)
 
 #define dh_arg_decl(t, n) glue(TCGv_, dh_alias(t)) glue(arg, n)
 
@@ -138,8 +158,8 @@ static inline void glue(gen_helper_, name)(dh_retvar_decl0(ret)) \
 static inline void glue(gen_helper_, name)(dh_retvar_decl(ret) dh_arg_decl(t1, 1)) \
 { \
   TCGArg args[1]; \
-  int sizemask; \
-  sizemask = dh_is_64bit(ret); \
+  int sizemask = 0; \
+  dh_sizemask(ret, 0); \
   dh_arg(t1, 1); \
   tcg_gen_helperN(HELPER(name), flags, sizemask, dh_retvar(ret), 1, args); \
 }
@@ -149,8 +169,8 @@ static inline void glue(gen_helper_, name)(dh_retvar_decl(ret) dh_arg_decl(t1, 1
     dh_arg_decl(t2, 2)) \
 { \
   TCGArg args[2]; \
-  int sizemask; \
-  sizemask = dh_is_64bit(ret); \
+  int sizemask = 0; \
+  dh_sizemask(ret, 0); \
   dh_arg(t1, 1); \
   dh_arg(t2, 2); \
   tcg_gen_helperN(HELPER(name), flags, sizemask, dh_retvar(ret), 2, args); \
@@ -161,8 +181,8 @@ static inline void glue(gen_helper_, name)(dh_retvar_decl(ret) dh_arg_decl(t1, 1
     dh_arg_decl(t2, 2), dh_arg_decl(t3, 3)) \
 { \
   TCGArg args[3]; \
-  int sizemask; \
-  sizemask = dh_is_64bit(ret); \
+  int sizemask = 0; \
+  dh_sizemask(ret, 0); \
   dh_arg(t1, 1); \
   dh_arg(t2, 2); \
   dh_arg(t3, 3); \
@@ -174,8 +194,8 @@ static inline void glue(gen_helper_, name)(dh_retvar_decl(ret) dh_arg_decl(t1, 1
     dh_arg_decl(t2, 2), dh_arg_decl(t3, 3), dh_arg_decl(t4, 4)) \
 { \
   TCGArg args[4]; \
-  int sizemask; \
-  sizemask = dh_is_64bit(ret); \
+  int sizemask = 0; \
+  dh_sizemask(ret, 0); \
   dh_arg(t1, 1); \
   dh_arg(t2, 2); \
   dh_arg(t3, 3); \
diff --git a/target-i386/ops_sse_header.h b/target-i386/ops_sse_header.h
index a0a6361..8d4b2b7 100644
--- a/target-i386/ops_sse_header.h
+++ b/target-i386/ops_sse_header.h
@@ -30,6 +30,9 @@
 #define dh_ctype_Reg Reg *
 #define dh_ctype_XMMReg XMMReg *
 #define dh_ctype_MMXReg MMXReg *
+#define dh_is_signed_Reg dh_is_signed_ptr
+#define dh_is_signed_XMMReg dh_is_signed_ptr
+#define dh_is_signed_MMXReg dh_is_signed_ptr
 
 DEF_HELPER_2(glue(psrlw, SUFFIX), void, Reg, Reg)
 DEF_HELPER_2(glue(psraw, SUFFIX), void, Reg, Reg)
diff --git a/target-ppc/helper.h b/target-ppc/helper.h
index 5cf6cd4..c025a2f 100644
--- a/target-ppc/helper.h
+++ b/target-ppc/helper.h
@@ -95,6 +95,7 @@ DEF_HELPER_3(fsel, i64, i64, i64, i64)
 
 #define dh_alias_avr ptr
 #define dh_ctype_avr ppc_avr_t *
+#define dh_is_signed_avr dh_is_signed_ptr
 
 DEF_HELPER_3(vaddubm, void, avr, avr, avr)
 DEF_HELPER_3(vadduhm, void, avr, avr, avr)
diff --git a/tcg/s390/tcg-target.h b/tcg/s390/tcg-target.h
index d7fe0c7..8c19262 100644
--- a/tcg/s390/tcg-target.h
+++ b/tcg/s390/tcg-target.h
@@ -87,6 +87,8 @@ enum {
 #define TCG_TARGET_STACK_ALIGN		8
 #define TCG_TARGET_CALL_STACK_OFFSET	0
 
+#define TCG_TARGET_EXTEND_ARGS 1
+
 enum {
     /* Note: must be synced with dyngen-exec.h */
     TCG_AREG0 = TCG_REG_R10,
diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h
index aa436de..4220e3d 100644
--- a/tcg/tcg-op.h
+++ b/tcg/tcg-op.h
@@ -369,8 +369,8 @@ static inline void tcg_gen_helperN(void *func, int flags, int sizemask,
    and pure, hence the call to tcg_gen_callN() with TCG_CALL_CONST |
    TCG_CALL_PURE. This may need to be adjusted if these functions
    start to be used with other helpers. */
-static inline void tcg_gen_helper32(void *func, TCGv_i32 ret,
-                                    TCGv_i32 a, TCGv_i32 b)
+static inline void tcg_gen_helper32(void *func, TCGv_i32 ret, TCGv_i32 a,
+                                    TCGv_i32 b, _Bool is_signed)
 {
     TCGv_ptr fn;
     TCGArg args[2];
@@ -378,12 +378,12 @@ static inline void tcg_gen_helper32(void *func, TCGv_i32 ret,
     args[0] = GET_TCGV_I32(a);
     args[1] = GET_TCGV_I32(b);
     tcg_gen_callN(&tcg_ctx, fn, TCG_CALL_CONST | TCG_CALL_PURE,
-                  0, GET_TCGV_I32(ret), 2, args);
+                  (is_signed ? 0x2a : 0x00), GET_TCGV_I32(ret), 2, args);
     tcg_temp_free_ptr(fn);
 }
 
-static inline void tcg_gen_helper64(void *func, TCGv_i64 ret,
-                                    TCGv_i64 a, TCGv_i64 b)
+static inline void tcg_gen_helper64(void *func, TCGv_i64 ret, TCGv_i64 a,
+                                    TCGv_i64 b, _Bool is_signed)
 {
     TCGv_ptr fn;
     TCGArg args[2];
@@ -391,7 +391,7 @@ static inline void tcg_gen_helper64(void *func, TCGv_i64 ret,
     args[0] = GET_TCGV_I64(a);
     args[1] = GET_TCGV_I64(b);
     tcg_gen_callN(&tcg_ctx, fn, TCG_CALL_CONST | TCG_CALL_PURE,
-                  7, GET_TCGV_I64(ret), 2, args);
+                  (is_signed ? 0x3f : 0x15), GET_TCGV_I64(ret), 2, args);
     tcg_temp_free_ptr(fn);
 }
 
@@ -692,22 +692,22 @@ static inline void tcg_gen_remu_i32(TCGv_i32 ret, TCGv_i32 arg1, TCGv_i32 arg2)
 #else
 static inline void tcg_gen_div_i32(TCGv_i32 ret, TCGv_i32 arg1, TCGv_i32 arg2)
 {
-    tcg_gen_helper32(tcg_helper_div_i32, ret, arg1, arg2);
+    tcg_gen_helper32(tcg_helper_div_i32, ret, arg1, arg2, 1);
 }
 
 static inline void tcg_gen_rem_i32(TCGv_i32 ret, TCGv_i32 arg1, TCGv_i32 arg2)
 {
-    tcg_gen_helper32(tcg_helper_rem_i32, ret, arg1, arg2);
+    tcg_gen_helper32(tcg_helper_rem_i32, ret, arg1, arg2, 1);
 }
 
 static inline void tcg_gen_divu_i32(TCGv_i32 ret, TCGv_i32 arg1, TCGv_i32 arg2)
 {
-    tcg_gen_helper32(tcg_helper_divu_i32, ret, arg1, arg2);
+    tcg_gen_helper32(tcg_helper_divu_i32, ret, arg1, arg2, 0);
 }
 
 static inline void tcg_gen_remu_i32(TCGv_i32 ret, TCGv_i32 arg1, TCGv_i32 arg2)
 {
-    tcg_gen_helper32(tcg_helper_remu_i32, ret, arg1, arg2);
+    tcg_gen_helper32(tcg_helper_remu_i32, ret, arg1, arg2, 0);
 }
 #endif
 
@@ -867,7 +867,7 @@ static inline void tcg_gen_xori_i64(TCGv_i64 ret, TCGv_i64 arg1, int64_t arg2)
    specific code (x86) */
 static inline void tcg_gen_shl_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 {
-    tcg_gen_helper64(tcg_helper_shl_i64, ret, arg1, arg2);
+    tcg_gen_helper64(tcg_helper_shl_i64, ret, arg1, arg2, 1);
 }
 
 static inline void tcg_gen_shli_i64(TCGv_i64 ret, TCGv_i64 arg1, int64_t arg2)
@@ -877,7 +877,7 @@ static inline void tcg_gen_shli_i64(TCGv_i64 ret, TCGv_i64 arg1, int64_t arg2)
 
 static inline void tcg_gen_shr_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 {
-    tcg_gen_helper64(tcg_helper_shr_i64, ret, arg1, arg2);
+    tcg_gen_helper64(tcg_helper_shr_i64, ret, arg1, arg2, 1);
 }
 
 static inline void tcg_gen_shri_i64(TCGv_i64 ret, TCGv_i64 arg1, int64_t arg2)
@@ -887,7 +887,7 @@ static inline void tcg_gen_shri_i64(TCGv_i64 ret, TCGv_i64 arg1, int64_t arg2)
 
 static inline void tcg_gen_sar_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 {
-    tcg_gen_helper64(tcg_helper_sar_i64, ret, arg1, arg2);
+    tcg_gen_helper64(tcg_helper_sar_i64, ret, arg1, arg2, 1);
 }
 
 static inline void tcg_gen_sari_i64(TCGv_i64 ret, TCGv_i64 arg1, int64_t arg2)
@@ -935,22 +935,22 @@ static inline void tcg_gen_mul_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 
 static inline void tcg_gen_div_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 {
-    tcg_gen_helper64(tcg_helper_div_i64, ret, arg1, arg2);
+    tcg_gen_helper64(tcg_helper_div_i64, ret, arg1, arg2, 1);
 }
 
 static inline void tcg_gen_rem_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 {
-    tcg_gen_helper64(tcg_helper_rem_i64, ret, arg1, arg2);
+    tcg_gen_helper64(tcg_helper_rem_i64, ret, arg1, arg2, 1);
 }
 
 static inline void tcg_gen_divu_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 {
-    tcg_gen_helper64(tcg_helper_divu_i64, ret, arg1, arg2);
+    tcg_gen_helper64(tcg_helper_divu_i64, ret, arg1, arg2, 0);
 }
 
 static inline void tcg_gen_remu_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 {
-    tcg_gen_helper64(tcg_helper_remu_i64, ret, arg1, arg2);
+    tcg_gen_helper64(tcg_helper_remu_i64, ret, arg1, arg2, 0);
 }
 
 #else
@@ -1212,22 +1212,22 @@ static inline void tcg_gen_remu_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 #else
 static inline void tcg_gen_div_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 {
-    tcg_gen_helper64(tcg_helper_div_i64, ret, arg1, arg2);
+    tcg_gen_helper64(tcg_helper_div_i64, ret, arg1, arg2, 1);
 }
 
 static inline void tcg_gen_rem_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 {
-    tcg_gen_helper64(tcg_helper_rem_i64, ret, arg1, arg2);
+    tcg_gen_helper64(tcg_helper_rem_i64, ret, arg1, arg2, 1);
 }
 
 static inline void tcg_gen_divu_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 {
-    tcg_gen_helper64(tcg_helper_divu_i64, ret, arg1, arg2);
+    tcg_gen_helper64(tcg_helper_divu_i64, ret, arg1, arg2, 0);
 }
 
 static inline void tcg_gen_remu_i64(TCGv_i64 ret, TCGv_i64 arg1, TCGv_i64 arg2)
 {
-    tcg_gen_helper64(tcg_helper_remu_i64, ret, arg1, arg2);
+    tcg_gen_helper64(tcg_helper_remu_i64, ret, arg1, arg2, 0);
 }
 #endif
 
diff --git a/tcg/tcg.c b/tcg/tcg.c
index 880e7ce..d8ddd1f 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -560,6 +560,24 @@ void tcg_gen_callN(TCGContext *s, TCGv_ptr func, unsigned int flags,
     int real_args;
     int nb_rets;
     TCGArg *nparam;
+
+#if defined(TCG_TARGET_EXTEND_ARGS) && TCG_TARGET_REG_BITS == 64
+    for (i = 0; i < nargs; ++i) {
+        int is_64bit = sizemask & (1 << (i+1)*2);
+        int is_signed = sizemask & (2 << (i+1)*2);
+        if (!is_64bit) {
+            TCGv_i64 temp = tcg_temp_new_i64();
+            TCGv_i64 orig = MAKE_TCGV_I64(args[i]);
+            if (is_signed) {
+                tcg_gen_ext32s_i64(temp, orig);
+            } else {
+                tcg_gen_ext32u_i64(temp, orig);
+            }
+            args[i] = GET_TCGV_I64(temp);
+        }
+    }
+#endif /* TCG_TARGET_EXTEND_ARGS */
+
     *gen_opc_ptr++ = INDEX_op_call;
     nparam = gen_opparam_ptr++;
 #ifdef TCG_TARGET_I386
@@ -588,7 +606,8 @@ void tcg_gen_callN(TCGContext *s, TCGv_ptr func, unsigned int flags,
     real_args = 0;
     for (i = 0; i < nargs; i++) {
 #if TCG_TARGET_REG_BITS < 64
-        if (sizemask & (2 << i)) {
+        int is_64bit = sizemask & (1 << (i+1)*2);
+        if (is_64bit) {
 #ifdef TCG_TARGET_I386
             /* REGPARM case: if the third parameter is 64 bit, it is
                allocated on the stack */
@@ -622,12 +641,12 @@ void tcg_gen_callN(TCGContext *s, TCGv_ptr func, unsigned int flags,
             *gen_opparam_ptr++ = args[i] + 1;
 #endif
             real_args += 2;
-        } else
-#endif
-        {
-            *gen_opparam_ptr++ = args[i];
-            real_args++;
+            continue;
         }
+#endif /* TCG_TARGET_REG_BITS < 64 */
+
+        *gen_opparam_ptr++ = args[i];
+        real_args++;
     }
     *gen_opparam_ptr++ = GET_TCGV_PTR(func);
 
@@ -637,6 +656,16 @@ void tcg_gen_callN(TCGContext *s, TCGv_ptr func, unsigned int flags,
 
     /* total parameters, needed to go backward in the instruction stream */
     *gen_opparam_ptr++ = 1 + nb_rets + real_args + 3;
+
+#if defined(TCG_TARGET_EXTEND_ARGS) && TCG_TARGET_REG_BITS == 64
+    for (i = 0; i < nargs; ++i) {
+        int is_64bit = sizemask & (1 << (i+1)*2);
+        if (!is_64bit) {
+            TCGv_i64 temp = MAKE_TCGV_I64(args[i]);
+            tcg_temp_free_i64(temp);
+        }
+    }
+#endif /* TCG_TARGET_EXTEND_ARGS */
 }
 
 #if TCG_TARGET_REG_BITS == 32
