X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FScalar%2FLoopUnrollPass.cpp;h=924be16beaaf641df180cd0857451188e08df469;hb=7520a90c75f339e03e3f37a20a9506dd7eb0061d;hp=ccc4a248476e3cea13fa309ac057360883f0566b;hpb=361ac0df6570558bd80b21e257a0a3e465cd20b4;p=oota-llvm.git

diff --git a/lib/Transforms/Scalar/LoopUnrollPass.cpp b/lib/Transforms/Scalar/LoopUnrollPass.cpp
index ccc4a248476..924be16beaa 100644
--- a/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -42,7 +42,7 @@ UnrollThreshold("unroll-threshold", cl::init(150), cl::Hidden,
   cl::desc("The cut-off point for automatic loop unrolling"));
 
 static cl::opt<unsigned> UnrollMaxIterationsCountToAnalyze(
-    "unroll-max-iteration-count-to-analyze", cl::init(1000), cl::Hidden,
+    "unroll-max-iteration-count-to-analyze", cl::init(0), cl::Hidden,
     cl::desc("Don't allow loop unrolling to simulate more than this number of"
              "iterations when checking full unroll profitability"));
 
@@ -213,9 +213,8 @@ namespace {
 
       PartialThreshold = UserThreshold ? CurrentThreshold : UP.PartialThreshold;
       if (!UserThreshold &&
-          L->getHeader()->getParent()->getAttributes().
-              hasAttribute(AttributeSet::FunctionIndex,
-                           Attribute::OptimizeForSize)) {
+          L->getHeader()->getParent()->hasFnAttribute(
+              Attribute::OptimizeForSize)) {
         Threshold = UP.OptSizeThreshold;
         PartialThreshold = UP.PartialOptSizeThreshold;
       }
@@ -453,10 +452,17 @@ public:
 
   // Given a list of loads that could be constant-folded (LoadBaseAddresses),
   // estimate number of optimized instructions after substituting the concrete
-  // values for the given Iteration.
-  // Fill in SimplifiedValues map for future use in DCE-estimation.
-  unsigned estimateNumberOfSimplifiedInstructions(unsigned Iteration) {
-    SmallVector<Instruction *, 8> Worklist;
+  // values for the given Iteration. Also track how many instructions become
+  // dead through this process.
+  unsigned estimateNumberOfOptimizedInstructions(unsigned Iteration) {
+    // We keep a set vector for the worklist so that we don't wast space in the
+    // worklist queuing up the same instruction repeatedly. This can happen due
+    // to multiple operands being the same instruction or due to the same
+    // instruction being an operand of lots of things that end up dead or
+    // simplified.
+    SmallSetVector<Instruction *, 8> Worklist;
+
+    // Clear the simplified values and counts for this iteration.
     SimplifiedValues.clear();
     CountedInstructions.clear();
     NumberOfOptimizedInstructions = 0;
@@ -468,14 +474,8 @@ public:
       if (CountedInstructions.insert(LI).second)
         NumberOfOptimizedInstructions += TTI.getUserCost(LI);
 
-      for (User *U : LI->users()) {
-        Instruction *UI = dyn_cast<Instruction>(U);
-        if (!UI)
-          continue;
-        if (!L->contains(UI))
-          continue;
-        Worklist.push_back(UI);
-      }
+      for (User *U : LI->users())
+        Worklist.insert(cast<Instruction>(U));
     }
 
     // And then we try to simplify every user of every instruction from the
@@ -483,31 +483,17 @@ public:
     // its users as well.
     while (!Worklist.empty()) {
       Instruction *I = Worklist.pop_back_val();
+      if (!L->contains(I))
+        continue;
       if (!visit(I))
         continue;
-      for (User *U : I->users()) {
-        Instruction *UI = dyn_cast<Instruction>(U);
-        if (!UI)
-          continue;
-        if (!L->contains(UI))
-          continue;
-        Worklist.push_back(UI);
-      }
+      for (User *U : I->users())
+        Worklist.insert(cast<Instruction>(U));
     }
-    return NumberOfOptimizedInstructions;
-  }
 
-  // Given a list of potentially simplifed instructions, estimate number of
-  // instructions that would become dead if we do perform the simplification.
-  unsigned estimateNumberOfDeadInstructions() {
-    NumberOfOptimizedInstructions = 0;
-
-    // We keep a set vector for the worklist so that we don't wast space in the
-    // worklist queuing up the same instruction repeatedly. This can happen due
-    // to multiple operands being the same instruction or due to the same
-    // instruction being an operand of lots of things that end up dead or
-    // simplified.
-    SmallSetVector<Instruction *, 8> Worklist;
+    // Now that we know the potentially simplifed instructions, estimate number
+    // of instructions that would become dead if we do perform the
+    // simplification.
 
     // The dead instructions are held in a separate set. This is used to
     // prevent us from re-examining instructions and make sure we only count
@@ -577,11 +563,10 @@ approximateNumberOfOptimizedInstructions(const Loop *L, ScalarEvolution &SE,
   unsigned IterationsNumberForEstimate =
       std::min<unsigned>(UnrollMaxIterationsCountToAnalyze, TripCount);
   unsigned NumberOfOptimizedInstructions = 0;
-  for (unsigned i = 0; i < IterationsNumberForEstimate; ++i) {
+  for (unsigned i = 0; i < IterationsNumberForEstimate; ++i)
     NumberOfOptimizedInstructions +=
-        UA.estimateNumberOfSimplifiedInstructions(i);
-    NumberOfOptimizedInstructions += UA.estimateNumberOfDeadInstructions();
-  }
+        UA.estimateNumberOfOptimizedInstructions(i);
+
   NumberOfOptimizedInstructions *= TripCount / IterationsNumberForEstimate;
 
   return NumberOfOptimizedInstructions;