Index: lib/Transforms/Scalar/LoopSimplifyCFG.cpp =================================================================== --- lib/Transforms/Scalar/LoopSimplifyCFG.cpp +++ lib/Transforms/Scalar/LoopSimplifyCFG.cpp @@ -239,7 +239,7 @@ if (!LiveLoopBlocks.count(From)) return false; BasicBlock *TheOnlySucc = getOnlyLiveSuccessor(From); - return !TheOnlySucc || TheOnlySucc == To; + return !TheOnlySucc || TheOnlySucc == To || LI.getLoopFor(From) != &L; }; // The loop will not be destroyed if its latch is live. Index: test/Transforms/LoopSimplifyCFG/live_block_marking.ll =================================================================== --- test/Transforms/LoopSimplifyCFG/live_block_marking.ll +++ test/Transforms/LoopSimplifyCFG/live_block_marking.ll @@ -4,11 +4,13 @@ ; RUN: opt -S -enable-loop-simplifycfg-term-folding=true -passes='require,loop(indvars,simplify-cfg)' -debug-only=loop-simplifycfg -verify-loop-info -verify-dom-info -verify-loop-lcssa 2>&1 < %s | FileCheck %s ; RUN: opt -S -enable-loop-simplifycfg-term-folding=true -indvars -loop-simplifycfg -enable-mssa-loop-dependency=true -verify-memoryssa -debug-only=loop-simplifycfg -verify-loop-info -verify-dom-info -verify-loop-lcssa 2>&1 < %s | FileCheck %s -; This test demonstrates a bug in live blocks markup that is only catchable in -; inter-pass interaction. define void @test(i1 %c) { ; CHECK-LABEL: @test( ; CHECK-NEXT: entry: +; CHECK-NEXT: switch i32 0, label [[ENTRY_SPLIT:%.*]] [ +; CHECK-NEXT: i32 1, label [[DEAD_EXIT:%.*]] +; CHECK-NEXT: ] +; CHECK: entry-split: ; CHECK-NEXT: br label [[OUTER:%.*]] ; CHECK: outer: ; CHECK-NEXT: br i1 [[C:%.*]], label [[TO_FOLD:%.*]], label [[LATCH:%.*]] @@ -25,7 +27,7 @@ ; CHECK: latch.loopexit: ; CHECK-NEXT: br label [[LATCH]] ; CHECK: latch: -; CHECK-NEXT: br i1 true, label [[OUTER]], label [[DEAD_EXIT:%.*]] +; CHECK-NEXT: br label [[OUTER]] ; CHECK: dead_exit: ; CHECK-NEXT: ret void ;