strength reduce this.

[oota-llvm.git] / lib / Analysis / LoopInfo.cpp

diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp
index b4333147a0c1fe262b9df3464b857bc1e3f2e5f8..05831402f4092bcea8ccf670e5864f8fdab03f40 100644 (file)
--- a/lib/Analysis/LoopInfo.cpp
+++ b/lib/Analysis/LoopInfo.cpp
@@ -38,7 +38,9 @@ VerifyLoopInfoX("verify-loop-info", cl::location(VerifyLoopInfo),
                 cl::desc("Verify loop info (time consuming)"));
 
 char LoopInfo::ID = 0;
-INITIALIZE_PASS(LoopInfo, "loops", "Natural Loop Information", true, true);
+INITIALIZE_PASS_BEGIN(LoopInfo, "loops", "Natural Loop Information", true, true)
+INITIALIZE_PASS_DEPENDENCY(DominatorTree)
+INITIALIZE_PASS_END(LoopInfo, "loops", "Natural Loop Information", true, true)
 
 //===----------------------------------------------------------------------===//
 // Loop implementation
@@ -48,15 +50,18 @@ INITIALIZE_PASS(LoopInfo, "loops", "Natural Loop Information", true, true);
 ///
 bool Loop::isLoopInvariant(Value *V) const {
   if (Instruction *I = dyn_cast<Instruction>(V))
-    return isLoopInvariant(I);
+    return !contains(I);
   return true;  // All non-instructions are loop invariant
 }
 
-/// isLoopInvariant - Return true if the specified instruction is
-/// loop-invariant.
-///
-bool Loop::isLoopInvariant(Instruction *I) const {
-  return !contains(I);
+/// hasLoopInvariantOperands - Return true if all the operands of the
+/// specified instruction are loop invariant. 
+bool Loop::hasLoopInvariantOperands(Instruction *I) const {
+  for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
+    if (!isLoopInvariant(I->getOperand(i)))
+      return false;
+  
+  return true;
 }
 
 /// makeLoopInvariant - If the given value is an instruciton inside of the
@@ -105,6 +110,7 @@ bool Loop::makeLoopInvariant(Instruction *I, bool &Changed,
   for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
     if (!makeLoopInvariant(I->getOperand(i), Changed, InsertPt))
       return false;
+  
   // Hoist.
   I->moveBefore(InsertPt);
   Changed = true;
@@ -155,18 +161,6 @@ PHINode *Loop::getCanonicalInductionVariable() const {
   return 0;
 }
 
-/// getCanonicalInductionVariableIncrement - Return the LLVM value that holds
-/// the canonical induction variable value for the "next" iteration of the
-/// loop.  This always succeeds if getCanonicalInductionVariable succeeds.
-///
-Instruction *Loop::getCanonicalInductionVariableIncrement() const {
-  if (PHINode *PN = getCanonicalInductionVariable()) {
-    bool P1InLoop = contains(PN->getIncomingBlock(1));
-    return cast<Instruction>(PN->getIncomingValue(P1InLoop));
-  }
-  return 0;
-}
-
 /// getTripCount - Return a loop-invariant LLVM value indicating the number of
 /// times the loop will be executed.  Note that this means that the backedge
 /// of the loop executes N-1 times.  If the trip-count cannot be determined,
@@ -178,12 +172,12 @@ Instruction *Loop::getCanonicalInductionVariableIncrement() const {
 Value *Loop::getTripCount() const {
   // Canonical loops will end with a 'cmp ne I, V', where I is the incremented
   // canonical induction variable and V is the trip count of the loop.
-  Instruction *Inc = getCanonicalInductionVariableIncrement();
-  if (Inc == 0) return 0;
-  PHINode *IV = cast<PHINode>(Inc->getOperand(0));
+  PHINode *IV = getCanonicalInductionVariable();
+  if (IV == 0 || IV->getNumIncomingValues() != 2) return 0;
 
-  BasicBlock *BackedgeBlock =
-    IV->getIncomingBlock(contains(IV->getIncomingBlock(1)));
+  bool P0InLoop = contains(IV->getIncomingBlock(0));
+  Value *Inc = IV->getIncomingValue(!P0InLoop);
+  BasicBlock *BackedgeBlock = IV->getIncomingBlock(!P0InLoop);
 
   if (BranchInst *BI = dyn_cast<BranchInst>(BackedgeBlock->getTerminator()))
     if (BI->isConditional()) {
@@ -204,7 +198,7 @@ Value *Loop::getTripCount() const {
 
 /// getSmallConstantTripCount - Returns the trip count of this loop as a
 /// normal unsigned value, if possible. Returns 0 if the trip count is unknown
-/// of not constant. Will also return 0 if the trip count is very large
+/// or not constant. Will also return 0 if the trip count is very large
 /// (>= 2^32)
 unsigned Loop::getSmallConstantTripCount() const {
   Value* TripCount = this->getTripCount();