[DFAJumpThreading] Dont insert existing edge to DomTree

Change-Id: Iddc75ba3a219458ee0c6dfefaa1c2a574cd44f9e

Author: UsmanNadeem

llvm/lib/Transforms/Scalar/DFAJumpThreading.cpp

@@ -266,8 +266,7 @@ void DFAJumpThreading::unfold(DomTreeUpdater *DTU, LoopInfo *LI,
     if (!ProfcheckDisableMetadataFixes)
       BI->setMetadata(LLVMContext::MD_prof,
                       SI->getMetadata(LLVMContext::MD_prof));
-    DTU->applyUpdates({{DominatorTree::Insert, StartBlock, EndBlock},
-                       {DominatorTree::Insert, StartBlock, NewBlock}});
+    DTU->applyUpdates({{DominatorTree::Insert, StartBlock, NewBlock}});
   } else {
     BasicBlock *EndBlock = SIUse->getParent();
     BasicBlock *NewBlockT = BasicBlock::Create(

llvm/test/Transforms/DFAJumpThreading/dfa-jump-threading-transform.ll

@@ -470,11 +470,9 @@ define i16 @DTU_update_crash() {
 ; CHECK-NEXT:    [[P_24_ADDR_3_JT0:%.*]] = phi i32 [ 0, [[FOR_BODY_SELECTBLOCK]] ], [ 0, [[SEL_SI_UNFOLD_FALSE_JT0]] ]
 ; CHECK-NEXT:    br label [[FOR_INC]]
 ; CHECK:       for.inc:
-; CHECK-NEXT:    [[P_24_ADDR_31:%.*]] = phi i32 [ [[P_24_ADDR_3_JT0]], [[SWITCHBLOCK_JT0]] ], [ [[P_24_ADDR_3]], [[SWITCHBLOCK]] ]
 ; CHECK-NEXT:    br i1 false, label [[FOR_BODY_SELECTBLOCK]], label [[CLEANUP]]
 ; CHECK:       cleanup:
-; CHECK-NEXT:    [[P_24_ADDR_32:%.*]] = phi i32 [ [[P_24_ADDR_31]], [[FOR_INC]] ], [ [[P_24_ADDR_3]], [[SWITCHBLOCK]] ], [ [[P_24_ADDR_3]], [[SWITCHBLOCK]] ]
-; CHECK-NEXT:    call void (...) @llvm.fake.use(i32 [[P_24_ADDR_32]])
+; CHECK-NEXT:    call void (...) @llvm.fake.use(i32 [[P_24_ADDR_3_JT0]])
 ; CHECK-NEXT:    ret i16 0
 ;
 entry:
@@ -506,6 +504,8 @@ declare void @llvm.fake.use(...)
 !0 = !{!"function_entry_count", i32 10}
 !1 = !{!"branch_weights", i32 3, i32 5}
 ;.
+; CHECK: attributes #[[ATTR0:[0-9]+]] = { nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: readwrite) }
+;.
 ; CHECK: [[META0:![0-9]+]] = !{!"function_entry_count", i32 10}
 ; CHECK: [[PROF1]] = !{!"branch_weights", i32 3, i32 5}
 ;.