JIT: fix finally target flags after some flow graph updates

src/coreclr/jit/compiler.h

@@ -4633,6 +4633,8 @@ class Compiler
 
     void fgAddFinallyTargetFlags();
 
+    void fgFixFinallyTargetFlags(BasicBlock* pred, BasicBlock* succ, BasicBlock* newBlock);
+
 #endif // defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
     PhaseStatus fgTailMergeThrows();
     void fgTailMergeThrowsFallThroughHelper(BasicBlock* predBlock,

src/coreclr/jit/fgbasic.cpp

@@ -584,6 +584,10 @@ void Compiler::fgReplaceJumpTarget(BasicBlock* block, BasicBlock* newTarget, Bas
             unreached();
             break;
     }
+
+#if defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
+    fgFixFinallyTargetFlags(block, oldTarget, newTarget);
+#endif
 }
 
 //------------------------------------------------------------------------
@@ -4779,6 +4783,10 @@ BasicBlock* Compiler::fgSplitEdge(BasicBlock* curr, BasicBlock* succ)
         fgAddRefPred(newBlock, curr);
     }
 
+#if defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
+    fgFixFinallyTargetFlags(curr, succ, newBlock);
+#endif
+
     // This isn't accurate, but it is complex to compute a reasonable number so just assume that we take the
     // branch 50% of the time.
     //

src/coreclr/jit/fgehopt.cpp

@@ -1620,6 +1620,32 @@ void Compiler::fgAddFinallyTargetFlags()
     }
 }
 
+//------------------------------------------------------------------------
+// fgFixFinallyTargetFlags: Update BBF_FINALLY_TARGET bits after redirecting flow
+//
+// Arguments:
+//   pred - source of flow
+//   succ - original target of flow from pred
+//   newSucc - new target of flow from pred
+//
+void Compiler::fgFixFinallyTargetFlags(BasicBlock* pred, BasicBlock* succ, BasicBlock* newSucc)
+{
+    if (pred->isBBCallAlwaysPairTail())
+    {
+        assert(succ->bbFlags & BBF_FINALLY_TARGET);
+        newSucc->bbFlags |= BBF_FINALLY_TARGET;
+        succ->bbFlags &= ~BBF_FINALLY_TARGET;
+
+        for (BasicBlock* const pred : succ->PredBlocks())
+        {
+            if (pred->isBBCallAlwaysPairTail())
+            {
+                succ->bbFlags |= BBF_FINALLY_TARGET;
+                break;
+            }
+        }
+    }
+}
 #endif // defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
 
 //------------------------------------------------------------------------

src/coreclr/jit/fgprofile.cpp

@@ -522,6 +522,10 @@ void BlockCountInstrumentor::RelocateProbes()
                 {
                     m_comp->fgRemoveRefPred(pred, block);
                     m_comp->fgAddRefPred(intermediary, block);
+
+#if defined(FEATURE_EH_FUNCLETS) && defined(TARGET_ARM)
+                    m_comp->fgFixFinallyTargetFlags(pred, block, intermediary);
+#endif
                 }
             }
         }