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.

2 files changed, 5 insertions, 4 deletions

diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index 07e1b55afe5..13538683e05 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/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);
                 }
                 _ => {}
diff --git a/compiler/rustc_codegen_llvm/src/consts.rs b/compiler/rustc_codegen_llvm/src/consts.rs
index e1baf95e1d9..ec92bd686d2 100644
--- a/compiler/rustc_codegen_llvm/src/consts.rs
+++ b/compiler/rustc_codegen_llvm/src/consts.rs
@@ -16,7 +16,9 @@ use rustc_middle::mir::interpret::{
 use rustc_middle::mir::mono::MonoItem;
 use rustc_middle::ty::{self, Instance, Ty};
 use rustc_middle::{bug, span_bug};
-use rustc_target::abi::{AddressSpace, Align, HasDataLayout, LayoutOf, Primitive, Scalar, Size};
+use rustc_target::abi::{
+    AddressSpace, Align, HasDataLayout, LayoutOf, Primitive, Scalar, Size, WrappingRange,
+};
 use tracing::debug;
 
 pub fn const_alloc_to_llvm(cx: &CodegenCx<'ll, '_>, alloc: &Allocation) -> &'ll Value {
@@ -59,7 +61,7 @@ pub fn const_alloc_to_llvm(cx: &CodegenCx<'ll, '_>, alloc: &Allocation) -> &'ll
                 Pointer::new(alloc_id, Size::from_bytes(ptr_offset)),
                 &cx.tcx,
             ),
-            &Scalar { value: Primitive::Pointer, valid_range: 0..=!0 },
+            &Scalar { value: Primitive::Pointer, valid_range: WrappingRange { start: 0, end: !0 } },
             cx.type_i8p_ext(address_space),
         ));
         next_offset = offset + pointer_size;