From cbb70ce070d220642b038ea101d9c0f9fbf860d6 Mon Sep 17 00:00:00 2001
From: dim <dim@FreeBSD.org>
Date: Sun, 20 Feb 2011 12:57:14 +0000
Subject: Vendor import of llvm trunk r126079:
http://llvm.org/svn/llvm-project/llvm/trunk@126079
---
lib/Transforms/Utils/BasicBlockUtils.cpp | 157 ++++++++++++++-----------------
1 file changed, 73 insertions(+), 84 deletions(-)
(limited to 'lib/Transforms/Utils/BasicBlockUtils.cpp')
diff --git a/lib/Transforms/Utils/BasicBlockUtils.cpp b/lib/Transforms/Utils/BasicBlockUtils.cpp
index 093083a..acaea19 100644
--- a/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -19,8 +19,9 @@
#include "llvm/Constant.h"
#include "llvm/Type.h"
#include "llvm/Analysis/AliasAnalysis.h"
-#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/MemoryDependenceAnalysis.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Scalar.h"
@@ -63,12 +64,27 @@ void llvm::DeleteDeadBlock(BasicBlock *BB) {
/// any single-entry PHI nodes in it, fold them away. This handles the case
/// when all entries to the PHI nodes in a block are guaranteed equal, such as
/// when the block has exactly one predecessor.
-void llvm::FoldSingleEntryPHINodes(BasicBlock *BB) {
+void llvm::FoldSingleEntryPHINodes(BasicBlock *BB, Pass *P) {
+ if (!isa<PHINode>(BB->begin())) return;
+
+ AliasAnalysis *AA = 0;
+ MemoryDependenceAnalysis *MemDep = 0;
+ if (P) {
+ AA = P->getAnalysisIfAvailable<AliasAnalysis>();
+ MemDep = P->getAnalysisIfAvailable<MemoryDependenceAnalysis>();
+ }
+
while (PHINode *PN = dyn_cast<PHINode>(BB->begin())) {
if (PN->getIncomingValue(0) != PN)
PN->replaceAllUsesWith(PN->getIncomingValue(0));
else
PN->replaceAllUsesWith(UndefValue::get(PN->getType()));
+
+ if (MemDep)
+ MemDep->removeInstruction(PN); // Memdep updates AA itself.
+ else if (AA && isa<PointerType>(PN->getType()))
+ AA->deleteValue(PN);
+
PN->eraseFromParent();
}
}
@@ -110,7 +126,7 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P) {
if (isa<InvokeInst>(PredBB->getTerminator())) return false;
succ_iterator SI(succ_begin(PredBB)), SE(succ_end(PredBB));
- BasicBlock* OnlySucc = BB;
+ BasicBlock *OnlySucc = BB;
for (; SI != SE; ++SI)
if (*SI != OnlySucc) {
OnlySucc = 0; // There are multiple distinct successors!
@@ -131,10 +147,8 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P) {
}
// Begin by getting rid of unneeded PHIs.
- while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) {
- PN->replaceAllUsesWith(PN->getIncomingValue(0));
- BB->getInstList().pop_front(); // Delete the phi node...
- }
+ if (isa<PHINode>(BB->front()))
+ FoldSingleEntryPHINodes(BB, P);
// Delete the unconditional branch from the predecessor...
PredBB->getInstList().pop_back();
@@ -152,24 +166,27 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P) {
// Finally, erase the old block and update dominator info.
if (P) {
- if (DominatorTree* DT = P->getAnalysisIfAvailable<DominatorTree>()) {
- DomTreeNode* DTN = DT->getNode(BB);
- DomTreeNode* PredDTN = DT->getNode(PredBB);
-
- if (DTN) {
- SmallPtrSet<DomTreeNode*, 8> Children(DTN->begin(), DTN->end());
- for (SmallPtrSet<DomTreeNode*, 8>::iterator DI = Children.begin(),
+ if (DominatorTree *DT = P->getAnalysisIfAvailable<DominatorTree>()) {
+ if (DomTreeNode *DTN = DT->getNode(BB)) {
+ DomTreeNode *PredDTN = DT->getNode(PredBB);
+ SmallVector<DomTreeNode*, 8> Children(DTN->begin(), DTN->end());
+ for (SmallVector<DomTreeNode*, 8>::iterator DI = Children.begin(),
DE = Children.end(); DI != DE; ++DI)
DT->changeImmediateDominator(*DI, PredDTN);
DT->eraseNode(BB);
}
+
+ if (LoopInfo *LI = P->getAnalysisIfAvailable<LoopInfo>())
+ LI->removeBlock(BB);
+
+ if (MemoryDependenceAnalysis *MD =
+ P->getAnalysisIfAvailable<MemoryDependenceAnalysis>())
+ MD->invalidateCachedPredecessors();
}
}
BB->eraseFromParent();
-
-
return true;
}
@@ -218,52 +235,6 @@ void llvm::ReplaceInstWithInst(Instruction *From, Instruction *To) {
ReplaceInstWithInst(From->getParent()->getInstList(), BI, To);
}
-/// RemoveSuccessor - Change the specified terminator instruction such that its
-/// successor SuccNum no longer exists. Because this reduces the outgoing
-/// degree of the current basic block, the actual terminator instruction itself
-/// may have to be changed. In the case where the last successor of the block
-/// is deleted, a return instruction is inserted in its place which can cause a
-/// surprising change in program behavior if it is not expected.
-///
-void llvm::RemoveSuccessor(TerminatorInst *TI, unsigned SuccNum) {
- assert(SuccNum < TI->getNumSuccessors() &&
- "Trying to remove a nonexistant successor!");
-
- // If our old successor block contains any PHI nodes, remove the entry in the
- // PHI nodes that comes from this branch...
- //
- BasicBlock *BB = TI->getParent();
- TI->getSuccessor(SuccNum)->removePredecessor(BB);
-
- TerminatorInst *NewTI = 0;
- switch (TI->getOpcode()) {
- case Instruction::Br:
- // If this is a conditional branch... convert to unconditional branch.
- if (TI->getNumSuccessors() == 2) {
- cast<BranchInst>(TI)->setUnconditionalDest(TI->getSuccessor(1-SuccNum));
- } else { // Otherwise convert to a return instruction...
- Value *RetVal = 0;
-
- // Create a value to return... if the function doesn't return null...
- if (!BB->getParent()->getReturnType()->isVoidTy())
- RetVal = Constant::getNullValue(BB->getParent()->getReturnType());
-
- // Create the return...
- NewTI = ReturnInst::Create(TI->getContext(), RetVal);
- }
- break;
-
- case Instruction::Invoke: // Should convert to call
- case Instruction::Switch: // Should remove entry
- default:
- case Instruction::Ret: // Cannot happen, has no successors!
- llvm_unreachable("Unhandled terminator inst type in RemoveSuccessor!");
- }
-
- if (NewTI) // If it's a different instruction, replace.
- ReplaceInstWithInst(TI, NewTI);
-}
-
/// GetSuccessorNumber - Search for the specified successor of basic block BB
/// and return its position in the terminator instruction's list of
/// successors. It is an error to call this with a block that is not a
@@ -300,13 +271,13 @@ BasicBlock *llvm::SplitEdge(BasicBlock *BB, BasicBlock *Succ, Pass *P) {
assert(SP == BB && "CFG broken");
SP = NULL;
return SplitBlock(Succ, Succ->begin(), P);
- } else {
- // Otherwise, if BB has a single successor, split it at the bottom of the
- // block.
- assert(BB->getTerminator()->getNumSuccessors() == 1 &&
- "Should have a single succ!");
- return SplitBlock(BB, BB->getTerminator(), P);
}
+
+ // Otherwise, if BB has a single successor, split it at the bottom of the
+ // block.
+ assert(BB->getTerminator()->getNumSuccessors() == 1 &&
+ "Should have a single succ!");
+ return SplitBlock(BB, BB->getTerminator(), P);
}
/// SplitBlock - Split the specified block at the specified instruction - every
@@ -322,12 +293,12 @@ BasicBlock *llvm::SplitBlock(BasicBlock *Old, Instruction *SplitPt, Pass *P) {
// The new block lives in whichever loop the old one did. This preserves
// LCSSA as well, because we force the split point to be after any PHI nodes.
- if (LoopInfo* LI = P->getAnalysisIfAvailable<LoopInfo>())
+ if (LoopInfo *LI = P->getAnalysisIfAvailable<LoopInfo>())
if (Loop *L = LI->getLoopFor(Old))
L->addBasicBlockToLoop(New, LI->getBase());
if (DominatorTree *DT = P->getAnalysisIfAvailable<DominatorTree>()) {
- // Old dominates New. New node domiantes all other nodes dominated by Old.
+ // Old dominates New. New node dominates all other nodes dominated by Old.
DomTreeNode *OldNode = DT->getNode(Old);
std::vector<DomTreeNode *> Children;
for (DomTreeNode::iterator I = OldNode->begin(), E = OldNode->end();
@@ -340,9 +311,6 @@ BasicBlock *llvm::SplitBlock(BasicBlock *Old, Instruction *SplitPt, Pass *P) {
DT->changeImmediateDominator(*I, NewNode);
}
- if (DominanceFrontier *DF = P->getAnalysisIfAvailable<DominanceFrontier>())
- DF->splitBlock(Old);
-
return New;
}
@@ -354,10 +322,9 @@ BasicBlock *llvm::SplitBlock(BasicBlock *Old, Instruction *SplitPt, Pass *P) {
/// suffix of 'Suffix'.
///
/// This currently updates the LLVM IR, AliasAnalysis, DominatorTree,
-/// DominanceFrontier, LoopInfo, and LCCSA but no other analyses.
-/// In particular, it does not preserve LoopSimplify (because it's
-/// complicated to handle the case where one of the edges being split
-/// is an exit of a loop with other exits).
+/// LoopInfo, and LCCSA but no other analyses. In particular, it does not
+/// preserve LoopSimplify (because it's complicated to handle the case where one
+/// of the edges being split is an exit of a loop with other exits).
///
BasicBlock *llvm::SplitBlockPredecessors(BasicBlock *BB,
BasicBlock *const *Preds,
@@ -407,13 +374,10 @@ BasicBlock *llvm::SplitBlockPredecessors(BasicBlock *BB,
}
}
- // Update dominator tree and dominator frontier if available.
+ // Update dominator tree if available.
DominatorTree *DT = P ? P->getAnalysisIfAvailable<DominatorTree>() : 0;
if (DT)
DT->splitBlock(NewBB);
- if (DominanceFrontier *DF =
- P ? P->getAnalysisIfAvailable<DominanceFrontier>() : 0)
- DF->splitBlock(NewBB);
// Insert a new PHI node into NewBB for every PHI node in BB and that new PHI
// node becomes an incoming value for BB's phi node. However, if the Preds
@@ -545,7 +509,32 @@ void llvm::FindFunctionBackedges(const Function &F,
// Go up one level.
InStack.erase(VisitStack.pop_back_val().first);
}
- } while (!VisitStack.empty());
-
-
+ } while (!VisitStack.empty());
+}
+
+/// FoldReturnIntoUncondBranch - This method duplicates the specified return
+/// instruction into a predecessor which ends in an unconditional branch. If
+/// the return instruction returns a value defined by a PHI, propagate the
+/// right value into the return. It returns the new return instruction in the
+/// predecessor.
+ReturnInst *llvm::FoldReturnIntoUncondBranch(ReturnInst *RI, BasicBlock *BB,
+ BasicBlock *Pred) {
+ Instruction *UncondBranch = Pred->getTerminator();
+ // Clone the return and add it to the end of the predecessor.
+ Instruction *NewRet = RI->clone();
+ Pred->getInstList().push_back(NewRet);
+
+ // If the return instruction returns a value, and if the value was a
+ // PHI node in "BB", propagate the right value into the return.
+ for (User::op_iterator i = NewRet->op_begin(), e = NewRet->op_end();
+ i != e; ++i)
+ if (PHINode *PN = dyn_cast<PHINode>(*i))
+ if (PN->getParent() == BB)
+ *i = PN->getIncomingValueForBlock(Pred);
+
+ // Update any PHI nodes in the returning block to realize that we no
+ // longer branch to them.
+ BB->removePredecessor(Pred);
+ UncondBranch->eraseFromParent();
+ return cast<ReturnInst>(NewRet);
}
--
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