two minor changes: switch to the standard ValueToValueMapTy
map from ValueMapper.h (giving us access to its utilities)
and add a fastpath in the loop rotation code, avoiding expensive
ssa updator manipulation for values with nothing to update.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123057 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopRotation.cpp b/lib/Transforms/Scalar/LoopRotation.cpp
index 1e655fd..ba1a279 100644
--- a/lib/Transforms/Scalar/LoopRotation.cpp
+++ b/lib/Transforms/Scalar/LoopRotation.cpp
@@ -21,10 +21,10 @@
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/SSAUpdater.h"
+#include "llvm/Transforms/Utils/ValueMapper.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/SmallVector.h"
using namespace llvm;
#define MAX_HEADER_SIZE 16
@@ -177,7 +177,7 @@
// Begin by walking OrigHeader and populating ValueMap with an entry for
// each Instruction.
BasicBlock::iterator I = OrigHeader->begin(), E = OrigHeader->end();
- DenseMap<const Value *, Value *> ValueMap;
+ ValueToValueMapTy ValueMap;
// For PHI nodes, the value available in OldPreHeader is just the
// incoming value from OldPreHeader.
@@ -233,6 +233,11 @@
Value *OrigHeaderVal = I;
Value *OrigPreHeaderVal = ValueMap[OrigHeaderVal];
+ // If there are no uses of the value (e.g. because it returns void), there
+ // is nothing to rewrite.
+ if (OrigHeaderVal->use_empty() && OrigPreHeaderVal->use_empty())
+ continue;
+
// The value now exits in two versions: the initial value in the preheader
// and the loop "next" value in the original header.
SSA.Initialize(OrigHeaderVal->getType(), OrigHeaderVal->getName());