Reinstate r133435 and r133449 (reverted in r133499) now that the clang

self-hosted build failure has been fixed (r133512).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133513 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jay Foad
2011-06-21 10:33:19 +00:00
parent 69254f67a5
commit cd35e09a4a
18 changed files with 211 additions and 156 deletions

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@@ -153,13 +153,13 @@ bool llvm::MergeBlockIntoPredecessor(BasicBlock *BB, Pass *P) {
// Delete the unconditional branch from the predecessor...
PredBB->getInstList().pop_back();
// Move all definitions in the successor to the predecessor...
PredBB->getInstList().splice(PredBB->end(), BB->getInstList());
// Make all PHI nodes that referred to BB now refer to Pred as their
// source...
BB->replaceAllUsesWith(PredBB);
// Move all definitions in the successor to the predecessor...
PredBB->getInstList().splice(PredBB->end(), BB->getInstList());
// Inherit predecessors name if it exists.
if (!PredBB->hasName())
PredBB->takeName(BB);

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@@ -193,44 +193,22 @@ BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum,
// If there are any PHI nodes in DestBB, we need to update them so that they
// merge incoming values from NewBB instead of from TIBB.
if (PHINode *APHI = dyn_cast<PHINode>(DestBB->begin())) {
// This conceptually does:
// foreach (PHINode *PN in DestBB)
// PN->setIncomingBlock(PN->getIncomingBlock(TIBB), NewBB);
// but is optimized for two cases.
if (APHI->getNumIncomingValues() <= 8) { // Small # preds case.
unsigned BBIdx = 0;
for (BasicBlock::iterator I = DestBB->begin(); isa<PHINode>(I); ++I) {
// We no longer enter through TIBB, now we come in through NewBB.
// Revector exactly one entry in the PHI node that used to come from
// TIBB to come from NewBB.
PHINode *PN = cast<PHINode>(I);
// Reuse the previous value of BBIdx if it lines up. In cases where we
// have multiple phi nodes with *lots* of predecessors, this is a speed
// win because we don't have to scan the PHI looking for TIBB. This
// happens because the BB list of PHI nodes are usually in the same
// order.
if (PN->getIncomingBlock(BBIdx) != TIBB)
BBIdx = PN->getBasicBlockIndex(TIBB);
PN->setIncomingBlock(BBIdx, NewBB);
}
} else {
// However, the foreach loop is slow for blocks with lots of predecessors
// because PHINode::getIncomingBlock is O(n) in # preds. Instead, walk
// the user list of TIBB to find the PHI nodes.
SmallPtrSet<PHINode*, 16> UpdatedPHIs;
for (Value::use_iterator UI = TIBB->use_begin(), E = TIBB->use_end();
UI != E; ) {
Value::use_iterator Use = UI++;
if (PHINode *PN = dyn_cast<PHINode>(*Use)) {
// Remove one entry from each PHI.
if (PN->getParent() == DestBB && UpdatedPHIs.insert(PN))
PN->setOperand(Use.getOperandNo(), NewBB);
}
}
{
unsigned BBIdx = 0;
for (BasicBlock::iterator I = DestBB->begin(); isa<PHINode>(I); ++I) {
// We no longer enter through TIBB, now we come in through NewBB.
// Revector exactly one entry in the PHI node that used to come from
// TIBB to come from NewBB.
PHINode *PN = cast<PHINode>(I);
// Reuse the previous value of BBIdx if it lines up. In cases where we
// have multiple phi nodes with *lots* of predecessors, this is a speed
// win because we don't have to scan the PHI looking for TIBB. This
// happens because the BB list of PHI nodes are usually in the same
// order.
if (PN->getIncomingBlock(BBIdx) != TIBB)
BBIdx = PN->getBasicBlockIndex(TIBB);
PN->setIncomingBlock(BBIdx, NewBB);
}
}

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@@ -572,12 +572,12 @@ void llvm::CloneAndPruneFunctionInto(Function *NewFunc, const Function *OldFunc,
// removed, so we just need to splice the blocks.
BI->eraseFromParent();
// Move all the instructions in the succ to the pred.
I->getInstList().splice(I->end(), Dest->getInstList());
// Make all PHI nodes that referred to Dest now refer to I as their source.
Dest->replaceAllUsesWith(I);
// Move all the instructions in the succ to the pred.
I->getInstList().splice(I->end(), Dest->getInstList());
// Remove the dest block.
Dest->eraseFromParent();

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@@ -1097,15 +1097,15 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI) {
TheCall->replaceAllUsesWith(Returns[0]->getReturnValue());
}
// Update PHI nodes that use the ReturnBB to use the AfterCallBB.
BasicBlock *ReturnBB = Returns[0]->getParent();
ReturnBB->replaceAllUsesWith(AfterCallBB);
// Splice the code from the return block into the block that it will return
// to, which contains the code that was after the call.
BasicBlock *ReturnBB = Returns[0]->getParent();
AfterCallBB->getInstList().splice(AfterCallBB->begin(),
ReturnBB->getInstList());
// Update PHI nodes that use the ReturnBB to use the AfterCallBB.
ReturnBB->replaceAllUsesWith(AfterCallBB);
// Delete the return instruction now and empty ReturnBB now.
Returns[0]->eraseFromParent();
ReturnBB->eraseFromParent();
@@ -1125,8 +1125,8 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI) {
// Splice the code entry block into calling block, right before the
// unconditional branch.
OrigBB->getInstList().splice(Br, CalleeEntry->getInstList());
CalleeEntry->replaceAllUsesWith(OrigBB); // Update PHI nodes
OrigBB->getInstList().splice(Br, CalleeEntry->getInstList());
// Remove the unconditional branch.
OrigBB->getInstList().erase(Br);

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@@ -427,10 +427,6 @@ void llvm::MergeBasicBlockIntoOnlyPred(BasicBlock *DestBB, Pass *P) {
BasicBlock *PredBB = DestBB->getSinglePredecessor();
assert(PredBB && "Block doesn't have a single predecessor!");
// Splice all the instructions from PredBB to DestBB.
PredBB->getTerminator()->eraseFromParent();
DestBB->getInstList().splice(DestBB->begin(), PredBB->getInstList());
// Zap anything that took the address of DestBB. Not doing this will give the
// address an invalid value.
if (DestBB->hasAddressTaken()) {
@@ -445,6 +441,10 @@ void llvm::MergeBasicBlockIntoOnlyPred(BasicBlock *DestBB, Pass *P) {
// Anything that branched to PredBB now branches to DestBB.
PredBB->replaceAllUsesWith(DestBB);
// Splice all the instructions from PredBB to DestBB.
PredBB->getTerminator()->eraseFromParent();
DestBB->getInstList().splice(DestBB->begin(), PredBB->getInstList());
if (P) {
DominatorTree *DT = P->getAnalysisIfAvailable<DominatorTree>();
if (DT) {
@@ -660,12 +660,17 @@ bool llvm::EliminateDuplicatePHINodes(BasicBlock *BB) {
// them, which helps expose duplicates, but we have to check all the
// operands to be safe in case instcombine hasn't run.
uintptr_t Hash = 0;
// This hash algorithm is quite weak as hash functions go, but it seems
// to do a good enough job for this particular purpose, and is very quick.
for (User::op_iterator I = PN->op_begin(), E = PN->op_end(); I != E; ++I) {
// This hash algorithm is quite weak as hash functions go, but it seems
// to do a good enough job for this particular purpose, and is very quick.
Hash ^= reinterpret_cast<uintptr_t>(static_cast<Value *>(*I));
Hash = (Hash << 7) | (Hash >> (sizeof(uintptr_t) * CHAR_BIT - 7));
}
for (PHINode::block_iterator I = PN->block_begin(), E = PN->block_end();
I != E; ++I) {
Hash ^= reinterpret_cast<uintptr_t>(static_cast<BasicBlock *>(*I));
Hash = (Hash << 7) | (Hash >> (sizeof(uintptr_t) * CHAR_BIT - 7));
}
// Avoid colliding with the DenseMap sentinels ~0 and ~0-1.
Hash >>= 1;
// If we've never seen this hash value before, it's a unique PHI.

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@@ -47,6 +47,14 @@ static inline void RemapInstruction(Instruction *I,
if (It != VMap.end())
I->setOperand(op, It->second);
}
if (PHINode *PN = dyn_cast<PHINode>(I)) {
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
ValueToValueMapTy::iterator It = VMap.find(PN->getIncomingBlock(i));
if (It != VMap.end())
PN->setIncomingBlock(i, cast<BasicBlock>(It->second));
}
}
}
/// FoldBlockIntoPredecessor - Folds a basic block into its predecessor if it
@@ -75,13 +83,13 @@ static BasicBlock *FoldBlockIntoPredecessor(BasicBlock *BB, LoopInfo* LI) {
// Delete the unconditional branch from the predecessor...
OnlyPred->getInstList().pop_back();
// Move all definitions in the successor to the predecessor...
OnlyPred->getInstList().splice(OnlyPred->end(), BB->getInstList());
// Make all PHI nodes that referred to BB now refer to Pred as their
// source...
BB->replaceAllUsesWith(OnlyPred);
// Move all definitions in the successor to the predecessor...
OnlyPred->getInstList().splice(OnlyPred->end(), BB->getInstList());
std::string OldName = BB->getName();
// Erase basic block from the function...
@@ -247,16 +255,14 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count,
// the successor of the latch block. The successor of the exit block will
// be updated specially after unrolling all the way.
if (*BB != LatchBlock)
for (Value::use_iterator UI = (*BB)->use_begin(), UE = (*BB)->use_end();
UI != UE;) {
Instruction *UseInst = cast<Instruction>(*UI);
++UI;
if (isa<PHINode>(UseInst) && !L->contains(UseInst)) {
PHINode *phi = cast<PHINode>(UseInst);
Value *Incoming = phi->getIncomingValueForBlock(*BB);
phi->addIncoming(Incoming, New);
}
}
for (succ_iterator SI = succ_begin(*BB), SE = succ_end(*BB); SI != SE;
++SI)
if (!L->contains(*SI))
for (BasicBlock::iterator BBI = (*SI)->begin(), BBE = (*SI)->end();
PHINode *phi = dyn_cast<PHINode>(BBI); ++BBI) {
Value *Incoming = phi->getIncomingValueForBlock(*BB);
phi->addIncoming(Incoming, New);
}
// Keep track of new headers and latches as we create them, so that
// we can insert the proper branches later.
@@ -288,24 +294,20 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count,
// successor blocks, update them to use the appropriate values computed as the
// last iteration of the loop.
if (Count != 1) {
SmallPtrSet<PHINode*, 8> Users;
for (Value::use_iterator UI = LatchBlock->use_begin(),
UE = LatchBlock->use_end(); UI != UE; ++UI)
if (PHINode *phi = dyn_cast<PHINode>(*UI))
Users.insert(phi);
BasicBlock *LastIterationBB = cast<BasicBlock>(LastValueMap[LatchBlock]);
for (SmallPtrSet<PHINode*,8>::iterator SI = Users.begin(), SE = Users.end();
for (succ_iterator SI = succ_begin(LatchBlock), SE = succ_end(LatchBlock);
SI != SE; ++SI) {
PHINode *PN = *SI;
Value *InVal = PN->removeIncomingValue(LatchBlock, false);
// If this value was defined in the loop, take the value defined by the
// last iteration of the loop.
if (Instruction *InValI = dyn_cast<Instruction>(InVal)) {
if (L->contains(InValI))
InVal = LastValueMap[InVal];
for (BasicBlock::iterator BBI = (*SI)->begin(), BBE = (*SI)->end();
PHINode *PN = dyn_cast<PHINode>(BBI); ++BBI) {
Value *InVal = PN->removeIncomingValue(LatchBlock, false);
// If this value was defined in the loop, take the value defined by the
// last iteration of the loop.
if (Instruction *InValI = dyn_cast<Instruction>(InVal)) {
if (L->contains(InValI))
InVal = LastValueMap[InVal];
}
PN->addIncoming(InVal, LastIterationBB);
}
PN->addIncoming(InVal, LastIterationBB);
}
}
@@ -352,11 +354,16 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count,
// Replace the conditional branch with an unconditional one.
BranchInst::Create(Dest, Term);
Term->eraseFromParent();
// Merge adjacent basic blocks, if possible.
if (BasicBlock *Fold = FoldBlockIntoPredecessor(Dest, LI)) {
}
}
// Merge adjacent basic blocks, if possible.
for (unsigned i = 0, e = Latches.size(); i != e; ++i) {
BranchInst *Term = cast<BranchInst>(Latches[i]->getTerminator());
if (Term->isUnconditional()) {
BasicBlock *Dest = Term->getSuccessor(0);
if (BasicBlock *Fold = FoldBlockIntoPredecessor(Dest, LI))
std::replace(Latches.begin(), Latches.end(), Dest, Fold);
std::replace(Headers.begin(), Headers.end(), Dest, Fold);
}
}
}

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@@ -16,6 +16,7 @@
#include "llvm/Type.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/Instructions.h"
#include "llvm/Metadata.h"
#include "llvm/ADT/SmallVector.h"
using namespace llvm;
@@ -128,6 +129,19 @@ void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
"Referenced value not in value map!");
}
// Remap phi nodes' incoming blocks.
if (PHINode *PN = dyn_cast<PHINode>(I)) {
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
Value *V = MapValue(PN->getIncomingBlock(i), VMap, Flags);
// If we aren't ignoring missing entries, assert that something happened.
if (V != 0)
PN->setIncomingBlock(i, cast<BasicBlock>(V));
else
assert((Flags & RF_IgnoreMissingEntries) &&
"Referenced block not in value map!");
}
}
// Remap attached metadata.
SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
I->getAllMetadata(MDs);