Index: llvm/trunk/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp =================================================================== --- llvm/trunk/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp +++ llvm/trunk/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp @@ -1380,13 +1380,21 @@ DominatorTree &DT, LoopInfo &LI) { // Find all the dead blocks, and remove them from their successors. SmallVector DeadBlocks; - for (BasicBlock *BB : llvm::concat(L.blocks(), ExitBlocks)) + for (BasicBlock *BB : ExitBlocks) if (!DT.isReachableFromEntry(BB)) { for (BasicBlock *SuccBB : successors(BB)) SuccBB->removePredecessor(BB); DeadBlocks.push_back(BB); } + for (Loop *ParentL = &L; ParentL; ParentL = ParentL->getParentLoop()) + for (BasicBlock *BB : ParentL->blocks()) + if (!DT.isReachableFromEntry(BB)) { + for (BasicBlock *SuccBB : successors(BB)) + SuccBB->removePredecessor(BB); + DeadBlocks.push_back(BB); + } + SmallPtrSet DeadBlockSet(DeadBlocks.begin(), DeadBlocks.end()); @@ -1431,7 +1439,7 @@ // Actually delete the blocks now that they've been fully unhooked from the // IR. - for (auto *BB : DeadBlocks) + for (auto *BB : DeadBlockSet) BB->eraseFromParent(); } Index: llvm/trunk/test/Transforms/SimpleLoopUnswitch/delete-dead-blocks.ll =================================================================== --- llvm/trunk/test/Transforms/SimpleLoopUnswitch/delete-dead-blocks.ll +++ llvm/trunk/test/Transforms/SimpleLoopUnswitch/delete-dead-blocks.ll @@ -0,0 +1,45 @@ +; RUN: opt < %s -simple-loop-unswitch -enable-nontrivial-unswitch -S 2>&1 | FileCheck %s +; RUN: opt < %s -passes=unswitch -enable-nontrivial-unswitch -S 2>&1 | FileCheck %s +; +; Checking that (dead) blocks from inner loop are deleted after unswitch. +; +declare void @foo() + +; CHECK-LABEL: @Test +define void @Test(i32) { +entry: + br label %outer +outer: + %oi = phi i32 [ 0, %entry ], [ %oinc, %outer_continue] + br label %inner +inner: + %ii = phi i32 [ 0, %outer ], [ %iinc, %continue] + call void @foo() + switch i32 %0, label %get_out2 [ + i32 0, label %continue + i32 1, label %case1 + i32 2, label %get_out + ] +; +; since we unswitch on the above switch, %case1 and %continue blocks +; become dead in the original loop +; +; CHECK-NOT: case1: +case1: + br label %continue +; CHECK-NOT: {{^}}continue: +continue: + %iinc = add i32 %ii, 1 + %icmp = icmp eq i32 %ii, 100 + br i1 %icmp, label %inner, label %outer_continue + +outer_continue: + %oinc = add i32 %oi, 1 + %ocmp = icmp eq i32 %oi, 100 + br i1 %ocmp, label %outer, label %get_out + +get_out: + ret void +get_out2: + unreachable +}