Trim off a few more runtime checks

Author: saethlin

compiler/rustc_mir_transform/src/lib.rs

@@ -714,12 +714,9 @@ fn run_optimization_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
             &multiple_return_terminators::MultipleReturnTerminators,
             &deduplicate_blocks::DeduplicateBlocks,
             &large_enums::EnumSizeOpt { discrepancy: 128 },
-            &add_call_guards::CriticalCallEdges,
             // Cleanup for human readability, off by default.
             &prettify::ReorderBasicBlocks,
             &prettify::ReorderLocals,
-            // Dump the end result for testing and debugging purposes.
-            &dump_mir::Marker("PreCodegen"),
         ],
         Some(MirPhase::Runtime(RuntimePhase::Optimized)),
     );
@@ -795,6 +792,7 @@ pub fn build_codegen_mir<'tcx>(tcx: TyCtxt<'tcx>, instance: Instance<'tcx>) -> B
             &o1(simplify_branches::SimplifyConstCondition::PostMono),
             &o1(simplify::SimplifyCfg::PostMono),
             &add_call_guards::CriticalCallEdges,
+            &dump_mir::Marker("PreCodegen"),
         ],
         None,
     );

compiler/rustc_mir_transform/src/validate.rs

@@ -386,23 +386,6 @@ impl<'a, 'tcx> Visitor<'tcx> for CfgChecker<'a, 'tcx> {
                     }
                     self.check_unwind_edge(location, unwind);
 
-                    // The code generation assumes that there are no critical call edges. The
-                    // assumption is used to simplify inserting code that should be executed along
-                    // the return edge from the call. FIXME(tmiasko): Since this is a strictly code
-                    // generation concern, the code generation should be responsible for handling
-                    // it.
-                    if self.mir_phase >= MirPhase::Runtime(RuntimePhase::Optimized)
-                        && self.is_critical_call_edge(target, unwind)
-                    {
-                        self.fail(
-                            location,
-                            format!(
-                                "encountered critical edge in `Call` terminator {:?}",
-                                terminator.kind,
-                            ),
-                        );
-                    }
-
                     // The call destination place and Operand::Move place used as an argument might
                     // be passed by a reference to the callee. Consequently they cannot be packed.
                     if is_within_packed(self.tcx, &self.body.local_decls, destination).is_some() {