Inline debug_strict_*.

Author: cjgillot

Diff for: compiler/rustc_serialize/src/int_overflow.rs

@@ -20,6 +20,7 @@ macro_rules! impl_debug_strict_add {
     ($( $ty:ty )*) => {
         $(
             impl DebugStrictAdd for $ty {
+                #[inline(always)]
                 fn debug_strict_add(self, other: Self) -> Self {
                     if cfg!(debug_assertions) {
                         self + other
@@ -42,6 +43,7 @@ macro_rules! impl_debug_strict_sub {
     ($( $ty:ty )*) => {
         $(
             impl DebugStrictSub for $ty {
+                #[inline(always)]
                 fn debug_strict_sub(self, other: Self) -> Self {
                     if cfg!(debug_assertions) {
                         self - other