diff options
| -rw-r--r-- | llvm/lib/Transforms/IPO/GlobalConstifier.cpp | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/llvm/lib/Transforms/IPO/GlobalConstifier.cpp b/llvm/lib/Transforms/IPO/GlobalConstifier.cpp index 6f01f25f507..97518a34fab 100644 --- a/llvm/lib/Transforms/IPO/GlobalConstifier.cpp +++ b/llvm/lib/Transforms/IPO/GlobalConstifier.cpp @@ -39,6 +39,16 @@ namespace { Pass *llvm::createGlobalConstifierPass() { return new Constifier(); } +/// A lot of global constants are stored only in trivially dead setter +/// functions. Because we don't want to cycle between globaldce and this pass, +/// just do a simple check to catch the common case. +static bool ContainingFunctionIsTriviallyDead(Instruction *I) { + Function *F = I->getParent()->getParent(); + if (!F->hasInternalLinkage()) return false; + F->removeDeadConstantUsers(); + return F->use_empty(); +} + /// isStoredThrough - Return false if the specified pointer is provably never /// stored through. If we can't tell, we must conservatively assume it might. /// @@ -48,10 +58,13 @@ static bool isStoredThrough(Value *V) { if (isStoredThrough(CE)) return true; } else if (Instruction *I = dyn_cast<Instruction>(*UI)) { - if (I->getOpcode() == Instruction::GetElementPtr) { - if (isStoredThrough(I)) return true; - } else if (!isa<LoadInst>(*UI) && !isa<SetCondInst>(*UI)) - return true; // Any other non-load instruction might store! + if (!ContainingFunctionIsTriviallyDead(I)) { + if (I->getOpcode() == Instruction::GetElementPtr) { + if (isStoredThrough(I)) return true; + } else if (!isa<LoadInst>(*UI) && !isa<SetCondInst>(*UI)) { + return true; // Any other non-load instruction might store! + } + } } else { // Otherwise must be a global or some other user. return true; |
