[LVI] Add an API to LazyValueInfo so that it can export ConstantRanges

that it computes. Currently this is used for testing and precision
tuning, but it might be used by optimizations later.

Differential Revision: http://reviews.llvm.org/D19179

llvm-svn: 268291

1 files changed, 16 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
index cb1ad5e6525..cb26da55c87 100644
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -1485,6 +1485,22 @@ Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB,
   return nullptr;
 }
 
+ConstantRange LazyValueInfo::getConstantRange(Value *V, BasicBlock *BB,
+					      Instruction *CxtI) {
+  assert(V->getType()->isIntegerTy());
+  unsigned Width = V->getType()->getIntegerBitWidth();
+  const DataLayout &DL = BB->getModule()->getDataLayout();
+  LVILatticeVal Result =
+      getCache(PImpl, AC, &DL, DT).getValueInBlock(V, BB, CxtI);
+  assert(!Result.isConstant());
+  if (Result.isUndefined())
+    return ConstantRange(Width, /*isFullSet=*/false);
+  if (Result.isConstantRange())
+    return Result.getConstantRange();
+  else
+    return ConstantRange(Width, /*isFullSet=*/true);
+}
+
 /// Determine whether the specified value is known to be a
 /// constant on the specified edge. Return null if not.
 Constant *LazyValueInfo::getConstantOnEdge(Value *V, BasicBlock *FromBB,