Auto merge of rust-lang#68828 - oli-obk:inline_cycle, r=wesleywiser

Prevent query cycles in the MIR inliner

r? `@eddyb` `@wesleywiser`

cc `@rust-lang/wg-mir-opt`

The general design is that we have a new query that is run on the `validated_mir` instead of on the `optimized_mir`. That query is forced before going into the optimization pipeline, so as to not try to read from a stolen MIR.

The query should not be cached cross crate, as you should never call it for items from other crates. By its very design calls into other crates can never cause query cycles.

This is a pessimistic approach to inlining, since we strictly have more calls in the `validated_mir` than we have in `optimized_mir`, but that's not a problem imo.

Author: bors

core/src/iter/range.rs

@@ -200,6 +200,7 @@ macro_rules! step_identical_methods {
         }
 
         #[inline]
+        #[allow(arithmetic_overflow)]
         fn forward(start: Self, n: usize) -> Self {
             // In debug builds, trigger a panic on overflow.
             // This should optimize completely out in release builds.
@@ -211,6 +212,7 @@ macro_rules! step_identical_methods {
         }
 
         #[inline]
+        #[allow(arithmetic_overflow)]
         fn backward(start: Self, n: usize) -> Self {
             // In debug builds, trigger a panic on overflow.
             // This should optimize completely out in release builds.