[llvm-commits] [llvm] r39767 - /llvm/trunk/lib/Transforms/Scalar/LoopRotation.cpp
Devang Patel
dpatel at apple.com
Wed Jul 11 16:47:29 PDT 2007
Author: dpatel
Date: Wed Jul 11 18:47:28 2007
New Revision: 39767
URL: http://llvm.org/viewvc/llvm-project?rev=39767&view=rev
Log:
Preserve analysis info.
Modified:
llvm/trunk/lib/Transforms/Scalar/LoopRotation.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/LoopRotation.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopRotation.cpp?rev=39767&r1=39766&r2=39767&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopRotation.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopRotation.cpp Wed Jul 11 18:47:28 2007
@@ -18,7 +18,10 @@
#include "llvm/Instructions.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/LoopPass.h"
+#include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/Statistic.h"
@@ -55,6 +58,17 @@
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequiredID(LCSSAID);
AU.addPreservedID(LCSSAID);
+ AU.addPreserved<ScalarEvolution>();
+ AU.addPreserved<LoopInfo>();
+ AU.addRequiredID(LoopSimplifyID);
+ AU.addPreservedID(LoopSimplifyID);
+ AU.addPreserved<DominatorTree>();
+ // Request DominanceFrontier now, even though Loop Rotate does
+ // not use it. This allows Pass Manager to schedule Dominance
+ // Frontier early enough such that one LPPassManager can handle
+ // loop rotate as well as licm pass.
+ AU.addRequired<DominanceFrontier>();
+ AU.addPreserved<DominanceFrontier>();
}
// Helper functions
@@ -90,7 +104,7 @@
BasicBlock *OrigLatch;
BasicBlock *NewHeader;
BasicBlock *Exit;
-
+ LPPassManager *LPM_Ptr;
SmallVector<RenameData, MAX_HEADER_SIZE> LoopHeaderInfo;
};
@@ -103,9 +117,10 @@
/// Rotate Loop L as many times as possible. Return true if
/// loop is rotated at least once.
bool LoopRotate::runOnLoop(Loop *Lp, LPPassManager &LPM) {
-
+
bool RotatedOneLoop = false;
initialize();
+ LPM_Ptr = &LPM;
// One loop can be rotated multiple times.
while (rotateLoop(Lp,LPM)) {
@@ -152,6 +167,13 @@
if (ExitBlocks.size() > 1)
return false;
+ // Check size of original header and reject
+ // loop if it is very big.
+ if (OrigHeader->getInstList().size() > MAX_HEADER_SIZE)
+ return false;
+
+ // Now, this loop is suitable for rotation.
+
// Find new Loop header. NewHeader is a Header's one and only successor
// that is inside loop. Header's other successor is out side the
// loop. Otherwise loop is not suitable for rotation.
@@ -163,13 +185,6 @@
assert(L->contains(NewHeader) && !L->contains(Exit) &&
"Unable to determine loop header and exit blocks");
- // Check size of original header and reject
- // loop if it is very big.
- if (OrigHeader->getInstList().size() > MAX_HEADER_SIZE)
- return false;
-
- // Now, this loop is suitable for rotation.
-
// Copy PHI nodes and other instructions from original header
// into original pre-header. Unlike original header, original pre-header is
// not a member of loop.
@@ -314,18 +329,24 @@
U->replaceUsesOfWith(OldPhi, NewPhi);
continue;
}
-
- // Used inside Exit Block. Since we are in LCSSA form, U must be PHINode.
- assert (U->getParent() == Exit
- && "Need to propagate new PHI into Exit blocks");
- assert (isa<PHINode>(U) && "Use in Exit Block that is not PHINode");
-
- PHINode *UPhi = cast<PHINode>(U);
-
- // UPhi already has one incoming argument from original header.
- // Add second incoming argument from new Pre header.
- UPhi->addIncoming(ILoopHeaderInfo.PreHeader, OrigPreHeader);
+ // Used inside Exit Block. Since we are in LCSSA form, U must be PHINode.
+ if (U->getParent() == Exit) {
+ assert (isa<PHINode>(U) && "Use in Exit Block that is not PHINode");
+
+ PHINode *UPhi = cast<PHINode>(U);
+ // UPhi already has one incoming argument from original header.
+ // Add second incoming argument from new Pre header.
+ UPhi->addIncoming(ILoopHeaderInfo.PreHeader, OrigPreHeader);
+ } else {
+ // Used outside Exit block. Create a new PHI node from exit block
+ // to receive value from ne new header ane pre header.
+ PHINode *PN = new PHINode(U->getType(), U->getName());
+ PN->addIncoming(ILoopHeaderInfo.PreHeader, OrigPreHeader);
+ PN->addIncoming(OldPhi, OrigHeader);
+ Exit->getInstList().push_front(PN);
+ U->replaceUsesOfWith(OldPhi, PN);
+ }
}
}
@@ -461,10 +482,105 @@
"Expected only one incoming value from Original PreHeader");
}
+ if (DominatorTree *DT = getAnalysisToUpdate<DominatorTree>()) {
+ DT->addNewBlock(NewPreHeader, OrigPreHeader);
+ DT->changeImmediateDominator(L->getHeader(), NewPreHeader);
+ DT->changeImmediateDominator(Exit, OrigPreHeader);
+ for (Loop::block_iterator BI = L->block_begin(), BE = L->block_end();
+ BI != BE; ++BI) {
+ BasicBlock *B = *BI;
+ if (L->getHeader() != B) {
+ DomTreeNode *Node = DT->getNode(B);
+ if (Node && Node->getBlock() == OrigHeader)
+ DT->changeImmediateDominator(*BI, L->getHeader());
+ }
+ }
+ DT->changeImmediateDominator(OrigHeader, OrigLatch);
+ }
+
+ if(DominanceFrontier *DF = getAnalysisToUpdate<DominanceFrontier>()) {
+
+ // New Preheader's dominance frontier is Exit block.
+ DominanceFrontier::DomSetType NewPHSet;
+ NewPHSet.insert(Exit);
+ DF->addBasicBlock(NewPreHeader, NewPHSet);
+
+ // New Header's dominance frontier now includes itself and Exit block
+ DominanceFrontier::iterator HeadI = DF->find(L->getHeader());
+ if (HeadI != DF->end()) {
+ DominanceFrontier::DomSetType & HeaderSet = HeadI->second;
+ HeaderSet.clear();
+ HeaderSet.insert(L->getHeader());
+ HeaderSet.insert(Exit);
+ } else {
+ DominanceFrontier::DomSetType HeaderSet;
+ HeaderSet.insert(L->getHeader());
+ HeaderSet.insert(Exit);
+ DF->addBasicBlock(L->getHeader(), HeaderSet);
+ }
+
+ // Original header (new Loop Latch)'s dominance frontier is Exit.
+ DominanceFrontier::iterator LatchI = DF->find(L->getLoopLatch());
+ if (LatchI != DF->end()) {
+ DominanceFrontier::DomSetType &LatchSet = LatchI->second;
+ LatchSet = LatchI->second;
+ LatchSet.clear();
+ LatchSet.insert(Exit);
+ } else {
+ DominanceFrontier::DomSetType LatchSet;
+ LatchSet.insert(Exit);
+ DF->addBasicBlock(L->getHeader(), LatchSet);
+ }
+
+ // If a loop block dominates new loop latch then its frontier is
+ // new header and Exit.
+ BasicBlock *NewLatch = L->getLoopLatch();
+ DominatorTree *DT = getAnalysisToUpdate<DominatorTree>();
+ for (Loop::block_iterator BI = L->block_begin(), BE = L->block_end();
+ BI != BE; ++BI) {
+ BasicBlock *B = *BI;
+ if (DT->dominates(B, NewLatch)) {
+ DominanceFrontier::iterator BDFI = DF->find(B);
+ if (BDFI != DF->end()) {
+ DominanceFrontier::DomSetType &BSet = BDFI->second;
+ BSet = BDFI->second;
+ BSet.clear();
+ BSet.insert(L->getHeader());
+ BSet.insert(Exit);
+ } else {
+ DominanceFrontier::DomSetType BSet;
+ BSet.insert(L->getHeader());
+ BSet.insert(Exit);
+ DF->addBasicBlock(B, BSet);
+ }
+ }
+ }
+ }
+
+ // Preserve canonical loop form, which means Exit block should
+ // have only one predecessor.
+ BasicBlock *NExit = SplitEdge(L->getLoopLatch(), Exit, this);
+
+ // Preserve LCSSA.
+ BasicBlock::iterator I = Exit->begin(), E = Exit->end();
+ PHINode *PN = NULL;
+ for (; (PN = dyn_cast<PHINode>(I)); ++I) {
+ PHINode *NewPN = new PHINode(PN->getType(), PN->getName());
+ unsigned N = PN->getNumIncomingValues();
+ for (unsigned index = 0; index < N; ++index)
+ if (PN->getIncomingBlock(index) == NExit) {
+ NewPN->addIncoming(PN->getIncomingValue(index), L->getLoopLatch());
+ PN->setIncomingValue(index, NewPN);
+ PN->setIncomingBlock(index, NExit);
+ NExit->getInstList().push_front(NewPN);
+ }
+ }
+
assert (NewHeader && L->getHeader() == NewHeader
&& "Invalid loop header after loop rotation");
assert (NewPreHeader && L->getLoopPreheader() == NewPreHeader
&& "Invalid loop preheader after loop rotation");
assert (L->getLoopLatch()
&& "Invalid loop latch after loop rotation");
+
}
More information about the llvm-commits
mailing list