Auto merge of #116454 - tmiasko:small-dominators, r=cjgillot

Generalize small dominators optimization

* Use small dominators optimization from 640ede7b0a more generally.
* Merge `DefLocation` and `LocationExtended` since they serve the same purpose.

compiler/rustc_codegen_ssa/src/mir/analyze.rs

@@ -8,7 +8,7 @@ use rustc_index::bit_set::BitSet;
 use rustc_index::{IndexSlice, IndexVec};
 use rustc_middle::mir::traversal;
 use rustc_middle::mir::visit::{MutatingUseContext, NonMutatingUseContext, PlaceContext, Visitor};
-use rustc_middle::mir::{self, Location, TerminatorKind};
+use rustc_middle::mir::{self, DefLocation, Location, TerminatorKind};
 use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf};
 
 pub fn non_ssa_locals<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
@@ -67,21 +67,6 @@ enum LocalKind {
     SSA(DefLocation),
 }
 
-#[derive(Copy, Clone, PartialEq, Eq)]
-enum DefLocation {
-    Argument,
-    Body(Location),
-}
-
-impl DefLocation {
-    fn dominates(self, location: Location, dominators: &Dominators<mir::BasicBlock>) -> bool {
-        match self {
-            DefLocation::Argument => true,
-            DefLocation::Body(def) => def.successor_within_block().dominates(location, dominators),
-        }
-    }
-}
-
 struct LocalAnalyzer<'mir, 'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> {
     fx: &'mir FunctionCx<'a, 'tcx, Bx>,
     dominators: &'mir Dominators<mir::BasicBlock>,