[LoopInterchange] Add stats counter for number of interchanged loops.

Reviewers: samparker, karthikthecool, blitz.opensource

Reviewed By: samparker

Differential Revision: https://reviews.llvm.org/D45209

llvm-svn: 329269

llvm/lib/Transforms/Scalar/LoopInterchange.cpp

@@ -15,6 +15,7 @@
 
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/DependenceAnalysis.h"
@@ -51,6 +52,8 @@ using namespace llvm;
 
 #define DEBUG_TYPE "loop-interchange"
 
+STATISTIC(LoopsInterchanged, "Number of loops interchanged");
+
 static cl::opt<int> LoopInterchangeCostThreshold(
     "loop-interchange-threshold", cl::init(0), cl::Hidden,
     cl::desc("Interchange if you gain more than this number"));
@@ -616,6 +619,7 @@ struct LoopInterchange : public FunctionPass {
                                  LoopNestExit, LIL.hasInnerLoopReduction());
     LIT.transform();
     DEBUG(dbgs() << "Loops interchanged.\n");
+    LoopsInterchanged++;
     return true;
   }
 };

llvm/test/Transforms/LoopInterchange/call-instructions.ll

@@ -1,4 +1,5 @@
-; RUN: opt < %s -basicaa -loop-interchange -pass-remarks-missed='loop-interchange' -pass-remarks-output=%t -verify-loop-info -verify-dom-info
+; RUN: opt < %s -basicaa -loop-interchange -pass-remarks-missed='loop-interchange' -pass-remarks-output=%t -S \
+; RUN:     -stats 2>&1 | FileCheck -check-prefix=STATS %s
 ; RUN: FileCheck --input-file=%t %s
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
@@ -113,3 +114,6 @@ for1.loopexit:
 exit:
   ret void
 }
+
+; Check stats, we interchanged 1 out of 2 loops.
+; STATS: 1 loop-interchange - Number of loops interchanged