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[Analysis] simplify code for getSplatValue(); NFC

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AFAIK, this is only currently called by TTI, but it could be
used from instcombine or CGP to help solve problems like:
https://bugs.llvm.org/show_bug.cgi?id=37428
https://bugs.llvm.org/show_bug.cgi?id=42174

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@362810 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Sanjay Patel 2019-06-07 16:09:54 +00:00
parent 957624db46
commit 15d807a56c
1 changed files with 11 additions and 20 deletions
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31
lib/Analysis/VectorUtils.cpp
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@ -304,30 +304,21 @@ Value *llvm::findScalarElement(Value *V, unsigned EltNo) {
/// Get splat value if the input is a splat vector or return nullptr.
/// This function is not fully general. It checks only 2 cases:
/// the input value is (1) a splat constants vector or (2) a sequence
/// of instructions that broadcast a single value into a vector.
///
/// the input value is (1) a splat constant vector or (2) a sequence
/// of instructions that broadcasts a scalar at element 0.
const llvm::Value *llvm::getSplatValue(const Value *V) {
if (auto *C = dyn_cast<Constant>(V))
if (isa<VectorType>(V->getType()))
if (isa<VectorType>(V->getType()))
if (auto *C = dyn_cast<Constant>(V))
return C->getSplatValue();
auto *ShuffleInst = dyn_cast<ShuffleVectorInst>(V);
if (!ShuffleInst)
return nullptr;
// All-zero (or undef) shuffle mask elements.
for (int MaskElt : ShuffleInst->getShuffleMask())
if (MaskElt != 0 && MaskElt != -1)
return nullptr;
// The first shuffle source is 'insertelement' with index 0.
auto *InsertEltInst =
dyn_cast<InsertElementInst>(ShuffleInst->getOperand(0));
if (!InsertEltInst || !isa<ConstantInt>(InsertEltInst->getOperand(2)) ||
!cast<ConstantInt>(InsertEltInst->getOperand(2))->isZero())
return nullptr;
// shuf (inselt ?, Splat, 0), ?, <0, undef, 0, ...>
Value *Splat;
if (match(V, m_ShuffleVector(m_InsertElement(m_Value(), m_Value(Splat),
m_ZeroInt()),
m_Value(), m_ZeroInt())))
return Splat;
return InsertEltInst->getOperand(1);
return nullptr;
}
MapVector<Instruction *, uint64_t>