target-arm: Use TCG operation for Neon 64 bit negation

Use the TCG operation to do Neon 64 bit negations rather than calling
a helper routine for it.
Reviewed-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

target-arm/helper.h

@@ -339,7 +339,6 @@ DEF_HELPER_2(neon_mull_s16, i64, i32, i32)
 
 DEF_HELPER_1(neon_negl_u16, i64, i64)
 DEF_HELPER_1(neon_negl_u32, i64, i64)
-DEF_HELPER_1(neon_negl_u64, i64, i64)
 
 DEF_HELPER_2(neon_qabs_s8, i32, env, i32)
 DEF_HELPER_2(neon_qabs_s16, i32, env, i32)

target-arm/neon_helper.c

@@ -1664,12 +1664,6 @@ uint64_t HELPER(neon_negl_u32)(uint64_t x)
     return low | ((uint64_t)high << 32);
 }
 
-/* FIXME:  There should be a native op for this.  */
-uint64_t HELPER(neon_negl_u64)(uint64_t x)
-{
-    return -x;
-}
-
 /* Saturating sign manipulation.  */
 /* ??? Make these use NEON_VOP1 */
 #define DO_QABS8(x) do { \

target-arm/translate.c

@@ -4184,7 +4184,9 @@ static inline void gen_neon_negl(TCGv_i64 var, int size)
     switch (size) {
     case 0: gen_helper_neon_negl_u16(var, var); break;
     case 1: gen_helper_neon_negl_u32(var, var); break;
-    case 2: gen_helper_neon_negl_u64(var, var); break;
+    case 2:
+        tcg_gen_neg_i64(var, var);
+        break;
     default: abort();
     }
 }