Revert "Revert "New interface function is added to VectorUtils Value *getSplatValue(Value *Val);""
This reverts commit r246379. It seems that the commit was not the culprit,
and the bot will be investigated for instability.
llvm-svn: 246380
diff --git a/llvm/lib/Analysis/VectorUtils.cpp b/llvm/lib/Analysis/VectorUtils.cpp
index 7214095..92a880c 100644
--- a/llvm/lib/Analysis/VectorUtils.cpp
+++ b/llvm/lib/Analysis/VectorUtils.cpp
@@ -18,6 +18,8 @@
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/PatternMatch.h"
#include "llvm/IR/Value.h"
+#include "llvm/IR/Constants.h"
+
using namespace llvm;
using namespace llvm::PatternMatch;
@@ -406,3 +408,27 @@
// Otherwise, we don't know.
return nullptr;
}
+
+/// \brief Get splat value if the input is a splat vector or return nullptr.
+/// The value may be extracted from a splat constants vector or from
+/// a sequence of instructions that broadcast a single value into a vector.
+llvm::Value *llvm::getSplatValue(Value *V) {
+ llvm::ConstantDataVector *CV = dyn_cast<llvm::ConstantDataVector>(V);
+ if (CV)
+ return CV->getSplatValue();
+ llvm::ShuffleVectorInst *ShuffleInst = dyn_cast<llvm::ShuffleVectorInst>(V);
+ if (!ShuffleInst)
+ return nullptr;
+ // All-zero (our undef) shuffle mask elements.
+ for (int i : ShuffleInst->getShuffleMask())
+ if (i != 0 && i != -1)
+ return nullptr;
+ // The first shuffle source is 'insertelement' with index 0.
+ llvm::InsertElementInst *InsertEltInst =
+ dyn_cast<llvm::InsertElementInst>(ShuffleInst->getOperand(0));
+ if (!InsertEltInst || !isa<ConstantInt>(InsertEltInst->getOperand(2)) ||
+ !cast<ConstantInt>(InsertEltInst->getOperand(2))->isNullValue())
+ return nullptr;
+
+ return InsertEltInst->getOperand(1);
+}