SimplifyConstCondition: Run again after CopyProp

Author: clubby789

compiler/rustc_mir_transform/src/lib.rs

@@ -610,10 +610,11 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
             &early_otherwise_branch::EarlyOtherwiseBranch,
             &simplify_comparison_integral::SimplifyComparisonIntegral,
             &dest_prop::DestinationPropagation,
-            &o1(simplify_branches::SimplifyConstCondition::Final),
+            &o1(simplify_branches::SimplifyConstCondition::AfterDestProp),
             &o1(remove_noop_landing_pads::RemoveNoopLandingPads),
             &o1(simplify::SimplifyCfg::Final),
             &copy_prop::CopyProp,
+            &o1(simplify_branches::SimplifyConstCondition::Final),
             &dead_store_elimination::DeadStoreElimination::Final,
             &nrvo::RenameReturnPlace,
             &simplify::SimplifyLocals::Final,

compiler/rustc_mir_transform/src/simplify_branches.rs

@@ -3,13 +3,15 @@ use rustc_middle::ty::TyCtxt;
 
 pub enum SimplifyConstCondition {
     AfterConstProp,
+    AfterDestProp,
     Final,
 }
 /// A pass that replaces a branch with a goto when its condition is known.
 impl<'tcx> MirPass<'tcx> for SimplifyConstCondition {
     fn name(&self) -> &'static str {
         match self {
             SimplifyConstCondition::AfterConstProp => "SimplifyConstCondition-after-const-prop",
+            SimplifyConstCondition::AfterDestProp => "SimplifyConstCondition-after-dest-prop",
             SimplifyConstCondition::Final => "SimplifyConstCondition-final",
         }
     }