[experiment]: Skip match simplification

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -7,7 +7,6 @@ use rustc_abi::{
 };
 use rustc_ast as ast;
 use rustc_ast::{InlineAsmOptions, InlineAsmTemplatePiece};
-use rustc_data_structures::packed::Pu128;
 use rustc_hir::attrs::AttributeKind;
 use rustc_hir::attrs::lang_items::LangItem;
 use rustc_lint_defs::builtin::TAIL_CALL_TRACK_CALLER;
@@ -454,39 +453,6 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 let cmp = bx.icmp(IntPredicate::IntEQ, discr_value, llval);
                 bx.cond_br_with_expect(cmp, lltarget, llotherwise, expect);
             }
-        } else if target_iter.len() == 2
-            && self.mir[targets.otherwise()].is_empty_unreachable()
-            && targets.all_values().contains(&Pu128(0))
-            && targets.all_values().contains(&Pu128(1))
-        {
-            // This is the really common case for `bool`, `Option`, etc.
-            // By using `trunc nuw` we communicate that other values are
-            // impossible without needing `switch` or `assume`s.
-            let true_bb = targets.target_for_value(1);
-            let false_bb = targets.target_for_value(0);
-            let true_ll = helper.llbb_with_cleanup(self, true_bb);
-            let false_ll = helper.llbb_with_cleanup(self, false_bb);
-
-            let expected_cond_value = if self.cx.sess().opts.optimize == OptLevel::No {
-                None
-            } else {
-                match (self.cold_blocks[true_bb], self.cold_blocks[false_bb]) {
-                    // Same coldness, no expectation
-                    (true, true) | (false, false) => None,
-                    // Different coldness, expect the non-cold one
-                    (true, false) => Some(false),
-                    (false, true) => Some(true),
-                }
-            };
-
-            let bool_ty = bx.tcx().types.bool;
-            let cond = if switch_ty == bool_ty {
-                discr_value
-            } else {
-                let bool_llty = bx.immediate_backend_type(bx.layout_of(bool_ty));
-                bx.unchecked_utrunc(discr_value, bool_llty)
-            };
-            bx.cond_br_with_expect(cond, true_ll, false_ll, expected_cond_value);
         } else if self.cx.sess().opts.optimize == OptLevel::No
             && target_iter.len() == 2
             && self.mir[targets.otherwise()].is_empty_unreachable()