X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FScalar%2FLowerExpectIntrinsic.cpp;h=2ace902a7a1b8f614ba5711842907d49a886b84b;hb=165b4f4e463eafb4a609a4b25362ca70b9eee8ef;hp=fa82d62b32f4c9304582cde865986bb5751e8aea;hpb=5999806dafb60f0dfc1b012234f906fdcf7f37d9;p=oota-llvm.git

diff --git a/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp b/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp
index fa82d62b32f..2ace902a7a1 100644
--- a/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp
+++ b/lib/Transforms/Scalar/LowerExpectIntrinsic.cpp
@@ -11,7 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Scalar/LowerExpectIntrinsic.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/IR/BasicBlock.h"
@@ -25,12 +25,14 @@
 #include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Transforms/Scalar.h"
 
 using namespace llvm;
 
 #define DEBUG_TYPE "lower-expect-intrinsic"
 
-STATISTIC(IfHandled, "Number of 'expect' intrinsic instructions handled");
+STATISTIC(ExpectIntrinsicsHandled,
+          "Number of 'expect' intrinsic instructions handled");
 
 static cl::opt<uint32_t>
 LikelyBranchWeight("likely-branch-weight", cl::Hidden, cl::init(64),
@@ -39,24 +41,6 @@ static cl::opt<uint32_t>
 UnlikelyBranchWeight("unlikely-branch-weight", cl::Hidden, cl::init(4),
                    cl::desc("Weight of the branch unlikely to be taken (default = 4)"));
 
-namespace {
-/// \brief Legacy pass for lowering expect intrinsics out of the IR.
-///
-/// When this pass is run over a function it uses expect intrinsics which feed
-/// branches and switches to provide branch weight metadata for those
-/// terminators. It then removes the expect intrinsics from the IR so the rest
-/// of the optimizer can ignore them.
-class LowerExpectIntrinsic : public FunctionPass {
-public:
-  static char ID;
-  LowerExpectIntrinsic() : FunctionPass(ID) {
-    initializeLowerExpectIntrinsicPass(*PassRegistry::getPassRegistry());
-  }
-
-  bool runOnFunction(Function &F) override;
-};
-}
-
 static bool handleSwitchExpect(SwitchInst &SI) {
   CallInst *CI = dyn_cast<CallInst>(SI.getCondition());
   if (!CI)
@@ -142,18 +126,20 @@ static bool handleBranchExpect(BranchInst &BI) {
   return true;
 }
 
-bool LowerExpectIntrinsic::runOnFunction(Function &F) {
+static bool lowerExpectIntrinsic(Function &F) {
+  bool Changed = false;
+
   for (BasicBlock &BB : F) {
     // Create "block_weights" metadata.
     if (BranchInst *BI = dyn_cast<BranchInst>(BB.getTerminator())) {
       if (handleBranchExpect(*BI))
-        IfHandled++;
+        ExpectIntrinsicsHandled++;
     } else if (SwitchInst *SI = dyn_cast<SwitchInst>(BB.getTerminator())) {
       if (handleSwitchExpect(*SI))
-        IfHandled++;
+        ExpectIntrinsicsHandled++;
     }
 
-    // remove llvm.expect intrinsics.
+    // Remove llvm.expect intrinsics.
     for (BasicBlock::iterator BI = BB.begin(), BE = BB.end(); BI != BE;) {
       CallInst *CI = dyn_cast<CallInst>(BI++);
       if (!CI)
@@ -164,11 +150,37 @@ bool LowerExpectIntrinsic::runOnFunction(Function &F) {
         Value *Exp = CI->getArgOperand(0);
         CI->replaceAllUsesWith(Exp);
         CI->eraseFromParent();
+        Changed = true;
       }
     }
   }
 
-  return false;
+  return Changed;
+}
+
+PreservedAnalyses LowerExpectIntrinsicPass::run(Function &F) {
+  if (lowerExpectIntrinsic(F))
+    return PreservedAnalyses::none();
+
+  return PreservedAnalyses::all();
+}
+
+namespace {
+/// \brief Legacy pass for lowering expect intrinsics out of the IR.
+///
+/// When this pass is run over a function it uses expect intrinsics which feed
+/// branches and switches to provide branch weight metadata for those
+/// terminators. It then removes the expect intrinsics from the IR so the rest
+/// of the optimizer can ignore them.
+class LowerExpectIntrinsic : public FunctionPass {
+public:
+  static char ID;
+  LowerExpectIntrinsic() : FunctionPass(ID) {
+    initializeLowerExpectIntrinsicPass(*PassRegistry::getPassRegistry());
+  }
+
+  bool runOnFunction(Function &F) override { return lowerExpectIntrinsic(F); }
+};
 }
 
 char LowerExpectIntrinsic::ID = 0;