Rollup merge of rust-lang#136786 - compiler-errors:de-de-duplicate-blocks, r=oli-obk

Remove the deduplicate_blocks pass

I don't think this pass does anything. It's a lot of complexity for 🤷  amount of benefit.

r? oli-obk

Author: matthiaskrgr

compiler/rustc_mir_transform/src/deduplicate_blocks.rs

@@ -135,7 +135,6 @@ declare_passes! {
         Initial,
         Final
     };
-    mod deduplicate_blocks : DeduplicateBlocks;
     mod deref_separator : Derefer;
     mod dest_prop : DestinationPropagation;
     pub mod dump_mir : Marker;
@@ -700,7 +699,6 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
             &nrvo::RenameReturnPlace,
             &simplify::SimplifyLocals::Final,
             &multiple_return_terminators::MultipleReturnTerminators,
-            &deduplicate_blocks::DeduplicateBlocks,
             &large_enums::EnumSizeOpt { discrepancy: 128 },
             // Some cleanup necessary at least for LLVM and potentially other codegen backends.
             &add_call_guards::CriticalCallEdges,