[region-isolation] Add support for debug_step.

Author: gottesmm

lib/SILOptimizer/Analysis/RegionAnalysis.cpp

@@ -2094,6 +2094,7 @@ CONSTANT_TRANSLATION(IsEscapingClosureInst, Ignored)
 CONSTANT_TRANSLATION(MetatypeInst, Ignored)
 CONSTANT_TRANSLATION(EndApplyInst, Ignored)
 CONSTANT_TRANSLATION(AbortApplyInst, Ignored)
+CONSTANT_TRANSLATION(DebugStepInst, Ignored)
 
 //===---
 // Require
@@ -2197,7 +2198,6 @@ CONSTANT_TRANSLATION(AssignInst, Unhandled)
 CONSTANT_TRANSLATION(AssignByWrapperInst, Unhandled)
 CONSTANT_TRANSLATION(AssignOrInitInst, Unhandled)
 CONSTANT_TRANSLATION(MarkFunctionEscapeInst, Unhandled)
-CONSTANT_TRANSLATION(DebugStepInst, Unhandled)
 CONSTANT_TRANSLATION(TestSpecificationInst, Unhandled)
 CONSTANT_TRANSLATION(StoreUnownedInst, Unhandled)
 CONSTANT_TRANSLATION(DeinitExistentialAddrInst, Unhandled)

test/Concurrency/transfernonsendable_instruction_matching.sil

@@ -831,4 +831,24 @@ bb0:
   destroy_value %value : $NonSendableKlass
   %9999 = tuple ()
   return %9999 : $()
-}
+}
+
+sil [ossa] @debug_step_test : $@convention(thin) @async () -> () {
+bb0:
+  %constructFn = function_ref @constructNonSendableKlass : $@convention(thin) () -> @owned NonSendableKlass
+  %value = apply %constructFn() : $@convention(thin) () -> @owned NonSendableKlass
+
+  %unowned = ref_to_unowned %value : $NonSendableKlass to $@sil_unowned NonSendableKlass
+  %ref = unowned_to_ref %unowned : $@sil_unowned NonSendableKlass to $NonSendableKlass
+  %refCopy = copy_value %ref : $NonSendableKlass
+  %transferNonSendableKlass = function_ref @transferNonSendableKlass : $@convention(thin) @async (@guaranteed NonSendableKlass) -> ()
+  apply [caller_isolation=nonisolated] [callee_isolation=global_actor] %transferNonSendableKlass(%refCopy) : $@convention(thin) @async (@guaranteed NonSendableKlass) -> ()
+
+  // Just make sure the pass sees the instruction
+  debug_step
+
+  destroy_value %refCopy : $NonSendableKlass
+  destroy_value %value : $NonSendableKlass
+  %9999 = tuple ()
+  return %9999 : $()
+}