diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp index 5d193c54282..08eb95a1a3d 100644 --- a/lib/Transforms/Scalar/JumpThreading.cpp +++ b/lib/Transforms/Scalar/JumpThreading.cpp @@ -1289,33 +1289,6 @@ bool JumpThreadingPass::ProcessThreadableEdges(Value *Cond, BasicBlock *BB, if (PredToDestList.empty()) return false; - // If all the predecessors go to a single known successor, we want to fold, - // not thread. By doing so, we do not need to duplicate the current block and - // also miss potential opportunities in case we don't/can't duplicate. - if (OnlyDest && OnlyDest != MultipleDestSentinel) { - if (PredToDestList.size() == - (size_t)std::distance(pred_begin(BB), pred_end(BB))) { - for (BasicBlock *SuccBB : successors(BB)) { - if (SuccBB != OnlyDest) - SuccBB->removePredecessor(BB, true); // This is unreachable successor. - } - - // Finally update the terminator. - TerminatorInst *Term = BB->getTerminator(); - BranchInst::Create(OnlyDest, Term); - Term->eraseFromParent(); - - // If the condition is now dead due to the removal of the old terminator, - // erase it. - auto *CondInst = dyn_cast(Cond); - if (CondInst && CondInst->use_empty()) - CondInst->eraseFromParent(); - // FIXME: in case this instruction is defined in the current BB and it - // resolves to a single value from all predecessors, we can do RAUW. - return true; - } - } - // Determine which is the most common successor. If we have many inputs and // this block is a switch, we want to start by threading the batch that goes // to the most popular destination first. If we only know about one diff --git a/test/Transforms/JumpThreading/basic.ll b/test/Transforms/JumpThreading/basic.ll index 2fd8c42adc9..14cd1fbe1c8 100644 --- a/test/Transforms/JumpThreading/basic.ll +++ b/test/Transforms/JumpThreading/basic.ll @@ -4,95 +4,6 @@ declare i32 @f1() declare i32 @f2() declare void @f3() -; Make sure we can fold this branch ... We will not be able to thread it as -; L0 is too big to duplicate. L2 is the unreachable block here. -; -; CHECK-LABEL: @test_br_folding_not_threading( -; CHECK: L1: -; CHECK: call i32 @f2() -; CHECK: call void @f3() -; CHECK-NEXT: ret void -; CHECK-NOT: br -; CHECK: L3: -define void @test_br_folding_not_threading(i1 %cond) nounwind { -entry: - br i1 %cond, label %L0, label %L3 -L0: - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - br i1 %cond, label %L1, label %L2 - -L1: - call void @f3() - ret void -L2: - call void @f3() - ret void -L3: - call void @f3() - ret void -} - - -; Make sure we can fold this branch ... We will not be able to thread it as -; L0 is too big to duplicate. L2 is the unreachable block here. -; With more than 1 predecessors. -; -; CHECK-LABEL: @test_br_folding_not_threading_multiple_preds( -; CHECK: L1: -; CHECK: call i32 @f2() -; CHECK: call void @f3() -; CHECK-NEXT: ret void -; CHECK-NOT: br -; CHECK: L3: -define void @test_br_folding_not_threading_multiple_preds(i1 %condx, i1 %cond) nounwind { -entry: - br i1 %condx, label %X0, label %X1 - -X0: - br i1 %cond, label %L0, label %L3 - -X1: - br i1 %cond, label %L0, label %L3 - -L0: - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - call i32 @f2() - br i1 %cond, label %L1, label %L2 - -L1: - call void @f3() - ret void -L2: - call void @f3() - ret void -L3: - call void @f3() - ret void -} - define i32 @test1(i1 %cond) { ; CHECK-LABEL: @test1(