diff options
| -rw-r--r-- | lib/Transforms/Utils/Local.cpp | 19 | ||||
| -rw-r--r-- | test/Instrumentation/MemorySanitizer/unreachable.ll | 16 |
2 files changed, 23 insertions, 12 deletions
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp index a54ee08b67..be80d34d96 100644 --- a/lib/Transforms/Utils/Local.cpp +++ b/lib/Transforms/Utils/Local.cpp @@ -985,22 +985,17 @@ bool llvm::removeUnreachableBlocks(Function &F) { if (Reachable.count(I)) continue; - // Remove the block as predecessor of all its reachable successors. - // Unreachable successors don't matter as they'll soon be removed, too. for (succ_iterator SI = succ_begin(I), SE = succ_end(I); SI != SE; ++SI) if (Reachable.count(*SI)) (*SI)->removePredecessor(I); + I->dropAllReferences(); + } - // Zap all instructions in this basic block. - while (!I->empty()) { - Instruction &Inst = I->back(); - if (!Inst.use_empty()) - Inst.replaceAllUsesWith(UndefValue::get(Inst.getType())); - I->getInstList().pop_back(); - } + for (Function::iterator I = llvm::next(F.begin()), E=F.end(); I != E;) + if (!Reachable.count(I)) + I = F.getBasicBlockList().erase(I); + else + ++I; - --I; - llvm::next(I)->eraseFromParent(); - } return true; } diff --git a/test/Instrumentation/MemorySanitizer/unreachable.ll b/test/Instrumentation/MemorySanitizer/unreachable.ll index 66a9575d3f..c8130717c7 100644 --- a/test/Instrumentation/MemorySanitizer/unreachable.ll +++ b/test/Instrumentation/MemorySanitizer/unreachable.ll @@ -21,3 +21,19 @@ exit: ; CHECK: @Func ; CHECK: store i32 0, {{.*}} @__msan_retval_tls ; CHECK: ret i32 42 + + +define i32 @UnreachableLoop() nounwind uwtable { +entry: + ret i32 0 + +zzz: + br label %xxx + +xxx: + br label %zzz +} + +; CHECK: @UnreachableLoop +; CHECK: store i32 0, {{.*}} @__msan_retval_tls +; CHECK: ret i32 0 |