From 34785ecff11854110344a4c8ab2d6165b883fb2b Mon Sep 17 00:00:00 2001
From: Adam Nemet <anemet@apple.com>
Date: Wed, 9 Mar 2016 05:33:21 +0000
Subject: [LoopDataPrefetch] Add stats and debug output

llvm-svn: 262998
---
 llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

(limited to 'llvm/lib')

diff --git a/llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp b/llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp
index 5d0a5906509..3d25e099c3e 100644
--- a/llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopDataPrefetch.cpp
@@ -43,6 +43,8 @@ static cl::opt<bool>
 PrefetchWrites("loop-prefetch-writes", cl::Hidden, cl::init(false),
                cl::desc("Prefetch write addresses"));
 
+STATISTIC(NumPrefetches, "Number of prefetches inserted");
+
 namespace llvm {
   void initializeLoopDataPrefetchPass(PassRegistry&);
 }
@@ -149,6 +151,10 @@ bool LoopDataPrefetch::runOnLoop(Loop *L) {
   if (!ItersAhead)
     ItersAhead = 1;
 
+  DEBUG(dbgs() << "Prefetching " << ItersAhead
+               << " iterations ahead (loop size: " << LoopSize << ") in "
+               << L->getHeader()->getParent()->getName() << ": " << *L);
+
   SmallVector<std::pair<Instruction *, const SCEVAddRecExpr *>, 16> PrefLoads;
   for (Loop::block_iterator I = L->block_begin(), IE = L->block_end();
        I != IE; ++I) {
@@ -219,6 +225,9 @@ bool LoopDataPrefetch::runOnLoop(Loop *L) {
           {PrefPtrValue,
            ConstantInt::get(I32, MemI->mayReadFromMemory() ? 0 : 1),
            ConstantInt::get(I32, 3), ConstantInt::get(I32, 1)});
+      ++NumPrefetches;
+      DEBUG(dbgs() << "  Access: " << *PtrValue << ", SCEV: " << *LSCEV
+                   << "\n");
 
       MadeChange = true;
     }
-- 
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