Generalize ScalarEvolution's PHI analysis to handle loops that don't

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

diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index 2e18ceac525eb50175ec7d0aa11d5ac90db5d466..1d1339078de5d7c52e8a28ec839abe36ad2799fc 100644 (file)
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -705,9 +705,11 @@ Value *SCEVExpander::visitAddExpr(const SCEVAddExpr *S) {
       Sum = expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, Sum);
     } else if (const PointerType *PTy = dyn_cast<PointerType>(Op->getType())) {
       // The running sum is an integer, and there's a pointer at this level.
-      // Try to form a getelementptr.
+      // Try to form a getelementptr. If the running sum is instructions,
+      // use a SCEVUnknown to avoid re-analyzing them.
       SmallVector<const SCEV *, 4> NewOps;
-      NewOps.push_back(SE.getUnknown(Sum));
+      NewOps.push_back(isa<Instruction>(Sum) ? SE.getUnknown(Sum) :
+                                               SE.getSCEV(Sum));
       for (++I; I != E && I->first == CurLoop; ++I)
         NewOps.push_back(I->second);
       Sum = expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, expand(Op));
@@ -966,9 +968,12 @@ Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
   // Determine a normalized form of this expression, which is the expression
   // before any post-inc adjustment is made.
   const SCEVAddRecExpr *Normalized = S;
-  if (L == PostIncLoop) {
-    const SCEV *Step = S->getStepRecurrence(SE);
-    Normalized = cast<SCEVAddRecExpr>(SE.getMinusSCEV(S, Step));
+  if (PostIncLoops.count(L)) {
+    PostIncLoopSet Loops;
+    Loops.insert(L);
+    Normalized =
+      cast<SCEVAddRecExpr>(TransformForPostIncUse(Normalize, S, 0, 0,
+                                                  Loops, SE, *SE.DT));
   }
 
   // Strip off any non-loop-dominating component from the addrec start.
@@ -1002,7 +1007,7 @@ Value *SCEVExpander::expandAddRecExprLiterally(const SCEVAddRecExpr *S) {
 
   // Accommodate post-inc mode, if necessary.
   Value *Result;
-  if (L != PostIncLoop)
+  if (!PostIncLoops.count(L))
     Result = PN;
   else {
     // In PostInc mode, use the post-incremented value.
@@ -1274,7 +1279,7 @@ Value *SCEVExpander::expand(const SCEV *S) {
       // If the SCEV is computable at this level, insert it into the header
       // after the PHIs (and after any other instructions that we've inserted
       // there) so that it is guaranteed to dominate any user inside the loop.
-      if (L && S->hasComputableLoopEvolution(L) && L != PostIncLoop)
+      if (L && S->hasComputableLoopEvolution(L) && !PostIncLoops.count(L))
         InsertPt = L->getHeader()->getFirstNonPHI();
       while (isInsertedInstruction(InsertPt) || isa<DbgInfoIntrinsic>(InsertPt))
         InsertPt = llvm::next(BasicBlock::iterator(InsertPt));
@@ -1296,7 +1301,7 @@ Value *SCEVExpander::expand(const SCEV *S) {
   Value *V = visit(S);
 
   // Remember the expanded value for this SCEV at this location.
-  if (!PostIncLoop)
+  if (PostIncLoops.empty())
     InsertedExpressions[std::make_pair(S, InsertPt)] = V;
 
   restoreInsertPoint(SaveInsertBB, SaveInsertPt);
@@ -1304,7 +1309,7 @@ Value *SCEVExpander::expand(const SCEV *S) {
 }
 
 void SCEVExpander::rememberInstruction(Value *I) {
-  if (!PostIncLoop)
+  if (PostIncLoops.empty())
     InsertedValues.insert(I);
 
   // If we just claimed an existing instruction and that instruction had