Auto merge of #131481 - nnethercote:rm-GenKillSet, r=cjgillot

Remove `GenKillAnalysis`

There are two kinds of dataflow analysis in the compiler: `Analysis`, which is the basic kind, and `GenKillAnalysis`, which is a more specialized kind for gen/kill analyses that is intended as an optimization. However, it turns out that `GenKillAnalysis` is actually a  pessimization! It's faster (and much simpler) to do all the gen/kill analyses via `Analysis`. This lets us remove `GenKillAnalysis`, and `GenKillSet`, and a few other things, and also merge `AnalysisDomain` into `Analysis`. The PR removes 500 lines of code and improves performance.

r? `@tmiasko`

1 files changed, 2 insertions, 7 deletions

diff --git a/compiler/rustc_const_eval/src/check_consts/resolver.rs b/compiler/rustc_const_eval/src/check_consts/resolver.rs
index eb5024c36f4..74eb6b37fbb 100644
--- a/compiler/rustc_const_eval/src/check_consts/resolver.rs
+++ b/compiler/rustc_const_eval/src/check_consts/resolver.rs
@@ -11,7 +11,7 @@ use rustc_middle::mir::{
     self, BasicBlock, CallReturnPlaces, Local, Location, Statement, StatementKind, TerminatorEdges,
 };
 use rustc_mir_dataflow::fmt::DebugWithContext;
-use rustc_mir_dataflow::{Analysis, AnalysisDomain, JoinSemiLattice};
+use rustc_mir_dataflow::{Analysis, JoinSemiLattice};
 
 use super::{ConstCx, Qualif, qualifs};
 
@@ -310,7 +310,7 @@ impl JoinSemiLattice for State {
     }
 }
 
-impl<'tcx, Q> AnalysisDomain<'tcx> for FlowSensitiveAnalysis<'_, '_, 'tcx, Q>
+impl<'tcx, Q> Analysis<'tcx> for FlowSensitiveAnalysis<'_, '_, 'tcx, Q>
 where
     Q: Qualif,
 {
@@ -328,12 +328,7 @@ where
     fn initialize_start_block(&self, _body: &mir::Body<'tcx>, state: &mut Self::Domain) {
         self.transfer_function(state).initialize_state();
     }
-}
 
-impl<'tcx, Q> Analysis<'tcx> for FlowSensitiveAnalysis<'_, '_, 'tcx, Q>
-where
-    Q: Qualif,
-{
     fn apply_statement_effect(
         &mut self,
         state: &mut Self::Domain,