diff options
| -rw-r--r-- | lib/Transforms/Scalar/GVN.cpp | 45 |
1 files changed, 2 insertions, 43 deletions
diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp index 732f6c8..9fe7786 100644 --- a/lib/Transforms/Scalar/GVN.cpp +++ b/lib/Transforms/Scalar/GVN.cpp @@ -701,7 +701,6 @@ namespace { bool processBlock(BasicBlock *BB); void dump(DenseMap<uint32_t, Value*>& d); bool iterateOnFunction(Function &F); - Value *CollapsePhi(PHINode* p); bool performPRE(Function& F); Value *lookupNumber(BasicBlock *BB, uint32_t num); void cleanupGlobalSets(); @@ -733,33 +732,6 @@ void GVN::dump(DenseMap<uint32_t, Value*>& d) { errs() << "}\n"; } -static bool isSafeReplacement(PHINode* p, Instruction *inst) { - if (!isa<PHINode>(inst)) - return true; - - for (Instruction::use_iterator UI = p->use_begin(), E = p->use_end(); - UI != E; ++UI) - if (PHINode* use_phi = dyn_cast<PHINode>(*UI)) - if (use_phi->getParent() == inst->getParent()) - return false; - - return true; -} - -Value *GVN::CollapsePhi(PHINode *PN) { - Value *ConstVal = PN->hasConstantValue(DT); - if (!ConstVal) return 0; - - Instruction *Inst = dyn_cast<Instruction>(ConstVal); - if (!Inst) - return ConstVal; - - if (DT->dominates(Inst, PN)) - if (isSafeReplacement(PN, Inst)) - return Inst; - return 0; -} - /// IsValueFullyAvailableInBlock - Return true if we can prove that the value /// we're analyzing is fully available in the specified block. As we go, keep /// track of which blocks we know are fully alive in FullyAvailableBlocks. This @@ -1954,21 +1926,8 @@ bool GVN::processInstruction(Instruction *I, return false; } - // Collapse PHI nodes - if (PHINode* p = dyn_cast<PHINode>(I)) { - Value *constVal = CollapsePhi(p); - - if (constVal) { - p->replaceAllUsesWith(constVal); - if (MD && constVal->getType()->isPointerTy()) - MD->invalidateCachedPointerInfo(constVal); - VN.erase(p); - - toErase.push_back(p); - } else { - localAvail[I->getParent()]->table.insert(std::make_pair(Num, I)); - } - + if (isa<PHINode>(I)) { + localAvail[I->getParent()]->table.insert(std::make_pair(Num, I)); // If the number we were assigned was a brand new VN, then we don't // need to do a lookup to see if the number already exists // somewhere in the domtree: it can't! |