Eliminate unnecessary copy of FileName from GCOVLines.

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

diff --git a/lib/Analysis/IVUsers.cpp b/lib/Analysis/IVUsers.cpp
index 2cda7913f024842e01a1f18d2363e24413716f90..e5f0a77ab67d57aba5910c31ecaefe85886425bd 100644 (file)
--- a/lib/Analysis/IVUsers.cpp
+++ b/lib/Analysis/IVUsers.cpp
@@ -46,17 +46,20 @@ Pass *llvm::createIVUsersPass() {
 /// used by the given expression, within the context of analyzing the
 /// given loop.
 static bool isInteresting(const SCEV *S, const Instruction *I, const Loop *L,
-                          ScalarEvolution *SE) {
+                          ScalarEvolution *SE, LoopInfo *LI) {
   // An addrec is interesting if it's affine or if it has an interesting start.
   if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
-    // Keep things simple. Don't touch loop-variant strides.
+    // Keep things simple. Don't touch loop-variant strides unless they're
+    // only used outside the loop and we can simplify them.
     if (AR->getLoop() == L)
-      return AR->isAffine() || !L->contains(I);
+      return AR->isAffine() ||
+             (!L->contains(I) &&
+              SE->getSCEVAtScope(AR, LI->getLoopFor(I->getParent())) != AR);
     // Otherwise recurse to see if the start value is interesting, and that
     // the step value is not interesting, since we don't yet know how to
     // do effective SCEV expansions for addrecs with interesting steps.
-    return isInteresting(AR->getStart(), I, L, SE) &&
-          !isInteresting(AR->getStepRecurrence(*SE), I, L, SE);
+    return isInteresting(AR->getStart(), I, L, SE, LI) &&
+          !isInteresting(AR->getStepRecurrence(*SE), I, L, SE, LI);
   }
 
   // An add is interesting if exactly one of its operands is interesting.
@@ -64,7 +67,7 @@ static bool isInteresting(const SCEV *S, const Instruction *I, const Loop *L,
     bool AnyInterestingYet = false;
     for (SCEVAddExpr::op_iterator OI = Add->op_begin(), OE = Add->op_end();
          OI != OE; ++OI)
-      if (isInteresting(*OI, I, L, SE)) {
+      if (isInteresting(*OI, I, L, SE, LI)) {
         if (AnyInterestingYet)
           return false;
         AnyInterestingYet = true;
@@ -98,7 +101,7 @@ bool IVUsers::AddUsersIfInteresting(Instruction *I) {
 
   // If we've come to an uninteresting expression, stop the traversal and
   // call this a user.
-  if (!isInteresting(ISE, I, L, SE))
+  if (!isInteresting(ISE, I, L, SE, LI))
     return false;
 
   SmallPtrSet<Instruction *, 4> UniqueUsers;
@@ -126,8 +129,7 @@ bool IVUsers::AddUsersIfInteresting(Instruction *I) {
                      << "   OF SCEV: " << *ISE << '\n');
         AddUserToIVUsers = true;
       }
-    } else if (Processed.count(User) ||
-               !AddUsersIfInteresting(User)) {
+    } else if (Processed.count(User) || !AddUsersIfInteresting(User)) {
       DEBUG(dbgs() << "FOUND USER: " << *User << '\n'
                    << "   OF SCEV: " << *ISE << '\n');
       AddUserToIVUsers = true;
@@ -137,7 +139,9 @@ bool IVUsers::AddUsersIfInteresting(Instruction *I) {
       // Okay, we found a user that we cannot reduce.
       IVUses.push_back(new IVStrideUse(this, User, I));
       IVStrideUse &NewUse = IVUses.back();
-      // Transform the expression into a normalized form.
+      // Autodetect the post-inc loop set, populating NewUse.PostIncLoops.
+      // The regular return value here is discarded; instead of recording
+      // it, we just recompute it when we need it.
       ISE = TransformForPostIncUse(NormalizeAutodetect,
                                    ISE, User, I,
                                    NewUse.PostIncLoops,