diff options
| -rw-r--r-- | llvm/lib/Transforms/IPO/GlobalOpt.cpp | 40 | ||||
| -rw-r--r-- | llvm/test/Transforms/GlobalOpt/2009-03-03-dbg.ll | 1 |
2 files changed, 31 insertions, 10 deletions
diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp index 0a35fa93e43..9284500a865 100644 --- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp +++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp @@ -137,17 +137,28 @@ struct VISIBILITY_HIDDEN GlobalStatus { } /// ConstantIsDead - Return true if the specified constant is (transitively) -/// dead. The constant may be used by other constants (e.g. constant arrays and -/// constant exprs) as long as they are dead, but it cannot be used by anything -/// else. -static bool ConstantIsDead(Constant *C) { +/// dead. The constant may be used by other constants (e.g. constant arrays, +/// constant exprs, constant global variables) as long as they are dead, +/// but it cannot be used by anything else. If DeadGVs is not null then +/// record dead constant GV users. +static bool ConstantIsDead(Constant *C, + SmallPtrSet<GlobalVariable *, 4> *DeadGVs = false) { if (isa<GlobalValue>(C)) return false; - for (Value::use_iterator UI = C->use_begin(), E = C->use_end(); UI != E; ++UI) - if (Constant *CU = dyn_cast<Constant>(*UI)) { - if (!ConstantIsDead(CU)) return false; + for (Value::use_iterator UI = C->use_begin(), E = C->use_end(); UI != E; ++UI) { + if (GlobalVariable *GV = dyn_cast<GlobalVariable>(*UI)) { + if (!GV->isConstant() || !GV->hasLocalLinkage() || !GV->use_empty()) + return false; + else { + if (DeadGVs) + DeadGVs->insert(GV); + } + } + else if (Constant *CU = dyn_cast<Constant>(*UI)) { + if (!ConstantIsDead(CU, DeadGVs)) return false; } else return false; + } return true; } @@ -338,8 +349,19 @@ static bool CleanupConstantGlobalUsers(Value *V, Constant *Init) { } else if (Constant *C = dyn_cast<Constant>(U)) { // If we have a chain of dead constantexprs or other things dangling from // us, and if they are all dead, nuke them without remorse. - if (ConstantIsDead(C)) { - C->destroyConstant(); + SmallPtrSet<GlobalVariable *, 4> DeadGVs; + if (ConstantIsDead(C, &DeadGVs)) { + for (SmallPtrSet<GlobalVariable *, 4>::iterator TI = DeadGVs.begin(), + TE = DeadGVs.end(); TI != TE; ) { + GlobalVariable *TGV = *TI; ++TI; + if (TGV == C) + C = NULL; + TGV->eraseFromParent(); + } + if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) + GV->eraseFromParent(); + else if (C) + C->destroyConstant(); // This could have invalidated UI, start over from scratch. CleanupConstantGlobalUsers(V, Init); return true; diff --git a/llvm/test/Transforms/GlobalOpt/2009-03-03-dbg.ll b/llvm/test/Transforms/GlobalOpt/2009-03-03-dbg.ll index 1996f621912..13d2f45d7a5 100644 --- a/llvm/test/Transforms/GlobalOpt/2009-03-03-dbg.ll +++ b/llvm/test/Transforms/GlobalOpt/2009-03-03-dbg.ll @@ -1,5 +1,4 @@ ; RUN: llvm-as < %s | opt -globalopt | llvm-dis | not grep global_variable42 -; XFAIL: * %llvm.dbg.anchor.type = type { i32, i32 } %llvm.dbg.basictype.type = type { i32, { }*, i8*, { }*, i32, i64, i64, i64, i32, i32 } |
