Cost model: Add check for reverse shuffles to CostModel analysis

Check for reverse shuffles in the CostModel analysis pass and query
TargetTransform info accordingly. This allows us we can write test cases for
reverse shuffles.

radar://13171406

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174932 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Arnold Schwaighofer 2013-02-12 02:40:37 +00:00
parent d9316dacf5
commit 4fc6484ee2

View File

@ -80,6 +80,13 @@ CostModelAnalysis::runOnFunction(Function &F) {
return false;
}
static bool isReverseVectorMask(SmallVector<int, 16> &Mask) {
for (unsigned i = 0, MaskSize = Mask.size(); i < MaskSize; ++i)
if (Mask[i] > 0 && Mask[i] != (int)(MaskSize - 1 - i))
return false;
return true;
}
unsigned CostModelAnalysis::getInstructionCost(const Instruction *I) const {
if (!TTI)
return -1;
@ -171,6 +178,17 @@ unsigned CostModelAnalysis::getInstructionCost(const Instruction *I) const {
return TTI->getVectorInstrCost(I->getOpcode(),
IE->getType(), Idx);
}
case Instruction::ShuffleVector: {
const ShuffleVectorInst *Shuffle = cast<ShuffleVectorInst>(I);
Type *VecTypOp0 = Shuffle->getOperand(0)->getType();
unsigned NumVecElems = VecTypOp0->getVectorNumElements();
SmallVector<int, 16> Mask = Shuffle->getShuffleMask();
if (NumVecElems == Mask.size() && isReverseVectorMask(Mask))
return TTI->getShuffleCost(TargetTransformInfo::SK_Reverse, VecTypOp0, 0,
0);
return -1;
}
default:
// We don't have any information on this instruction.
return -1;