From b392321cae84aa9ac37966ce0d3f73a34bee8b11 Mon Sep 17 00:00:00 2001 From: Nate Begeman Date: Thu, 4 Aug 2005 23:24:19 +0000 Subject: Fix a fixme in CondPropagate.cpp by moving a PhiNode optimization into BasicBlock's removePredecessor routine. This requires shuffling around the definition and implementation of hasContantValue from Utils.h,cpp into Instructions.h,cpp llvm-svn: 22664 --- llvm/lib/Transforms/Scalar/CondPropagate.cpp | 11 ------- .../lib/Transforms/Scalar/InstructionCombining.cpp | 2 +- llvm/lib/Transforms/Scalar/LoopSimplify.cpp | 5 ++-- llvm/lib/Transforms/Utils/Local.cpp | 34 ---------------------- .../Transforms/Utils/PromoteMemoryToRegister.cpp | 3 +- 5 files changed, 4 insertions(+), 51 deletions(-) (limited to 'llvm/lib/Transforms') diff --git a/llvm/lib/Transforms/Scalar/CondPropagate.cpp b/llvm/lib/Transforms/Scalar/CondPropagate.cpp index d3ad5778bb4..101acef6dcb 100644 --- a/llvm/lib/Transforms/Scalar/CondPropagate.cpp +++ b/llvm/lib/Transforms/Scalar/CondPropagate.cpp @@ -80,17 +80,6 @@ void CondProp::SimplifyBlock(BasicBlock *BB) { SimplifyPredecessors(SI); } - // See if we can fold any PHI nodes in this block now. - // FIXME: This would not be required if removePredecessor did this for us!! - PHINode *PN; - for (BasicBlock::iterator I = BB->begin(); (PN = dyn_cast(I++)); ) - if (Value *PNV = hasConstantValue(PN)) - if (!isa(PNV)) { - PN->replaceAllUsesWith(PNV); - PN->eraseFromParent(); - MadeChange = true; - } - // If possible, simplify the terminator of this block. if (ConstantFoldTerminator(BB)) MadeChange = true; diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index d644d279359..5767afc4099 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -4401,7 +4401,7 @@ static bool DeadPHICycle(PHINode *PN, std::set &PotentiallyDeadPHIs) { // PHINode simplification // Instruction *InstCombiner::visitPHINode(PHINode &PN) { - if (Value *V = hasConstantValue(&PN)) { + if (Value *V = PN.hasConstantValue()) { // If V is an instruction, we have to be certain that it dominates PN. // However, because we don't have dom info, we can't do a perfect job. if (Instruction *I = dyn_cast(V)) { diff --git a/llvm/lib/Transforms/Scalar/LoopSimplify.cpp b/llvm/lib/Transforms/Scalar/LoopSimplify.cpp index 3e4312681d1..5ddcc4163db 100644 --- a/llvm/lib/Transforms/Scalar/LoopSimplify.cpp +++ b/llvm/lib/Transforms/Scalar/LoopSimplify.cpp @@ -41,7 +41,6 @@ #include "llvm/Analysis/Dominators.h" #include "llvm/Analysis/LoopInfo.h" #include "llvm/Support/CFG.h" -#include "llvm/Transforms/Utils/Local.h" #include "llvm/ADT/SetOperations.h" #include "llvm/ADT/SetVector.h" #include "llvm/ADT/Statistic.h" @@ -257,7 +256,7 @@ BasicBlock *LoopSimplify::SplitBlockPredecessors(BasicBlock *BB, PN->addIncoming(InVal, NewBB); // Can we eliminate this phi node now? - if (Value *V = hasConstantValue(PN)) { + if (Value *V = PN->hasConstantValue()) { if (!isa(V) || getAnalysis().dominates(cast(V), PN)) { PN->replaceAllUsesWith(V); @@ -443,7 +442,7 @@ static PHINode *FindPHIToPartitionLoops(Loop *L, DominatorSet &DS, for (BasicBlock::iterator I = L->getHeader()->begin(); isa(I); ) { PHINode *PN = cast(I); ++I; - if (Value *V = hasConstantValue(PN)) + if (Value *V = PN->hasConstantValue()) if (!isa(V) || DS.dominates(cast(V), PN)) { // This is a degenerate PHI already, don't modify it! PN->replaceAllUsesWith(V); diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp index 4ce9d8f11a1..9744af3c605 100644 --- a/llvm/lib/Transforms/Utils/Local.cpp +++ b/llvm/lib/Transforms/Utils/Local.cpp @@ -406,37 +406,3 @@ bool llvm::dceInstruction(BasicBlock::iterator &BBI) { } return false; } - -//===----------------------------------------------------------------------===// -// PHI Instruction Simplification -// - -/// hasConstantValue - If the specified PHI node always merges together the same -/// value, return the value, otherwise return null. -/// -Value *llvm::hasConstantValue(PHINode *PN) { - // If the PHI node only has one incoming value, eliminate the PHI node... - if (PN->getNumIncomingValues() == 1) - return PN->getIncomingValue(0); - - // Otherwise if all of the incoming values are the same for the PHI, replace - // the PHI node with the incoming value. - // - Value *InVal = 0; - for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) - if (PN->getIncomingValue(i) != PN && // Not the PHI node itself... - !isa(PN->getIncomingValue(i))) - if (InVal && PN->getIncomingValue(i) != InVal) - return 0; // Not the same, bail out. - else - InVal = PN->getIncomingValue(i); - - // The only case that could cause InVal to be null is if we have a PHI node - // that only has entries for itself. In this case, there is no entry into the - // loop, so kill the PHI. - // - if (InVal == 0) InVal = UndefValue::get(PN->getType()); - - // All of the incoming values are the same, return the value now. - return InVal; -} diff --git a/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp b/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp index 1edc1193766..bb7f8680933 100644 --- a/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp +++ b/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp @@ -24,7 +24,6 @@ #include "llvm/Analysis/Dominators.h" #include "llvm/Analysis/AliasSetTracker.h" #include "llvm/ADT/StringExtras.h" -#include "llvm/Transforms/Utils/Local.h" #include "llvm/Support/CFG.h" #include "llvm/Support/StableBasicBlockNumbering.h" #include @@ -348,7 +347,7 @@ void PromoteMem2Reg::run() { PHINode *SomePHI = 0; for (unsigned i = 0, e = PNs.size(); i != e; ++i) if (PNs[i]) { - if (Value *V = hasConstantValue(PNs[i])) { + if (Value *V = PNs[i]->hasConstantValue()) { if (!isa(V) || dominates(cast(V), PNs[i])) { if (AST && isa(PNs[i]->getType())) AST->deleteValue(PNs[i]); -- cgit v1.2.3