#define DEBUG_TYPE "lcssa"
#include "llvm/Transforms/Scalar.h"
-#include "llvm/Constants.h"
-#include "llvm/Pass.h"
-#include "llvm/Function.h"
-#include "llvm/Instructions.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/Dominators.h"
#include "llvm/Analysis/LoopPass.h"
#include "llvm/Analysis/ScalarEvolution.h"
-#include "llvm/Transforms/Utils/SSAUpdater.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/Pass.h"
#include "llvm/Support/PredIteratorCache.h"
+#include "llvm/Transforms/Utils/SSAUpdater.h"
using namespace llvm;
STATISTIC(NumLCSSA, "Number of live out of a loop variables");
// Cached analysis information for the current function.
DominatorTree *DT;
+ LoopInfo *LI;
+ ScalarEvolution *SE;
std::vector<BasicBlock*> LoopBlocks;
PredIteratorCache PredCache;
Loop *L;
L = TheLoop;
DT = &getAnalysis<DominatorTree>();
+ LI = &getAnalysis<LoopInfo>();
+ SE = getAnalysisIfAvailable<ScalarEvolution>();
// Get the set of exiting blocks.
SmallVector<BasicBlock*, 8> ExitBlocks;
MadeChange |= ProcessInstruction(I, ExitBlocks);
}
}
+
+ // If we modified the code, remove any caches about the loop from SCEV to
+ // avoid dangling entries.
+ // FIXME: This is a big hammer, can we clear the cache more selectively?
+ if (SE && MadeChange)
+ SE->forgetLoop(L);
assert(L->isLCSSAForm(*DT));
PredCache.clear();
// If we already inserted something for this BB, don't reprocess it.
if (SSAUpdate.HasValueForBlock(ExitBB)) continue;
- PHINode *PN = PHINode::Create(Inst->getType(), Inst->getName()+".lcssa",
+ PHINode *PN = PHINode::Create(Inst->getType(),
+ PredCache.GetNumPreds(ExitBB),
+ Inst->getName()+".lcssa",
ExitBB->begin());
- PN->reserveOperandSpace(PredCache.GetNumPreds(ExitBB));
// Add inputs from inside the loop for this PHI.
for (BasicBlock **PI = PredCache.GetPreds(ExitBB); *PI; ++PI) {
// Remember that this phi makes the value alive in this block.
SSAUpdate.AddAvailableValue(ExitBB, PN);
}
-
+
// Rewrite all uses outside the loop in terms of the new PHIs we just
// inserted.
for (unsigned i = 0, e = UsesToRewrite.size(); i != e; ++i) {
if (isa<PHINode>(UserBB->begin()) &&
isExitBlock(UserBB, ExitBlocks)) {
+ // Tell the VHs that the uses changed. This updates SCEV's caches.
+ if (UsesToRewrite[i]->get()->hasValueHandle())
+ ValueHandleBase::ValueIsRAUWd(*UsesToRewrite[i], UserBB->begin());
UsesToRewrite[i]->set(UserBB->begin());
continue;
}