Auto merge of #88242 - bonega:allocation_range, r=oli-obk

Use custom wrap-around type instead of RangeInclusive

Two reasons:

1. More memory is allocated than necessary for `valid_range` in `Scalar`. The range is not used as an iterator and `exhausted` is never used.
2. `contains`, `count` etc. methods in `RangeInclusive` are doing very unhelpful(and dangerous!) things when used as a wrap-around range. - In general this PR wants to limit potentially confusing methods, that have a low probability of working.

Doing a local perf run, every metric shows improvement except for instructions.
Max-rss seem to have a very consistent improvement.

Sorry - newbie here, probably doing something wrong.

compiler/rustc_codegen_llvm/src/builder.rs

@@ -462,7 +462,6 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
             load: &'ll Value,
             scalar: &abi::Scalar,
         ) {
-            let vr = scalar.valid_range.clone();
             match scalar.value {
                 abi::Int(..) => {
                     let range = scalar.valid_range_exclusive(bx);
@@ -470,7 +469,7 @@ impl BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
                         bx.range_metadata(load, range);
                     }
                 }
-                abi::Pointer if vr.start() < vr.end() && !vr.contains(&0) => {
+                abi::Pointer if !scalar.valid_range.contains_zero() => {
                     bx.nonnull_metadata(load);
                 }
                 _ => {}