Rollup merge of #79027 - tmiasko:inline-always-live-locals, r=oli-obk

Limit storage duration of inlined always live locals

Closes #76375.

compiler/rustc_middle/src/mir/mod.rs

@@ -420,7 +420,9 @@ impl<'tcx> Body<'tcx> {
     /// Returns an iterator over all user-defined variables and compiler-generated temporaries (all
     /// locals that are neither arguments nor the return place).
     #[inline]
-    pub fn vars_and_temps_iter(&self) -> impl Iterator<Item = Local> + ExactSizeIterator {
+    pub fn vars_and_temps_iter(
+        &self,
+    ) -> impl DoubleEndedIterator<Item = Local> + ExactSizeIterator {
         let arg_count = self.arg_count;
         let local_count = self.local_decls.len();
         (arg_count + 1..local_count).map(Local::new)