CostModel: Add parameter to instruction cost to further classify operand values
On certain architectures we can support efficient vectorized version of
instructions if the operand value is uniform (splat) or a constant scalar.
An example of this is a vector shift on x86.
We can efficiently support
for (i = 0 ; i < ; i += 4)
w[0:3] = v[0:3] << <2, 2, 2, 2>
but not
for (i = 0; i < ; i += 4)
w[0:3] = v[0:3] << x[0:3]
This patch adds a parameter to getArithmeticInstrCost to further qualify operand
values as uniform or uniform constant.
Targets can then choose to return a different cost for instructions with such
operand values.
A follow-up commit will test this feature on x86.
radar://13576547
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178807 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/CostModel.cpp b/lib/Analysis/CostModel.cpp
index df70d15..98a7780 100644
--- a/lib/Analysis/CostModel.cpp
+++ b/lib/Analysis/CostModel.cpp
@@ -88,6 +88,23 @@
return true;
}
+static TargetTransformInfo::OperandValueKind getOperandInfo(Value *V) {
+ TargetTransformInfo::OperandValueKind OpInfo =
+ TargetTransformInfo::OK_AnyValue;
+
+ // Check for a splat of a constant.
+ ConstantDataVector *CDV = 0;
+ if ((CDV = dyn_cast<ConstantDataVector>(V)))
+ if (CDV->getSplatValue() != NULL)
+ OpInfo = TargetTransformInfo::OK_UniformConstantValue;
+ ConstantVector *CV = 0;
+ if ((CV = dyn_cast<ConstantVector>(V)))
+ if (CV->getSplatValue() != NULL)
+ OpInfo = TargetTransformInfo::OK_UniformConstantValue;
+
+ return OpInfo;
+}
+
unsigned CostModelAnalysis::getInstructionCost(const Instruction *I) const {
if (!TTI)
return -1;
@@ -121,7 +138,12 @@
case Instruction::And:
case Instruction::Or:
case Instruction::Xor: {
- return TTI->getArithmeticInstrCost(I->getOpcode(), I->getType());
+ TargetTransformInfo::OperandValueKind Op1VK =
+ getOperandInfo(I->getOperand(0));
+ TargetTransformInfo::OperandValueKind Op2VK =
+ getOperandInfo(I->getOperand(1));
+ return TTI->getArithmeticInstrCost(I->getOpcode(), I->getType(), Op1VK,
+ Op2VK);
}
case Instruction::Select: {
const SelectInst *SI = cast<SelectInst>(I);
diff --git a/lib/Analysis/TargetTransformInfo.cpp b/lib/Analysis/TargetTransformInfo.cpp
index 976cd87..64f8e96 100644
--- a/lib/Analysis/TargetTransformInfo.cpp
+++ b/lib/Analysis/TargetTransformInfo.cpp
@@ -150,8 +150,10 @@
}
unsigned TargetTransformInfo::getArithmeticInstrCost(unsigned Opcode,
- Type *Ty) const {
- return PrevTTI->getArithmeticInstrCost(Opcode, Ty);
+ Type *Ty,
+ OperandValueKind Op1Info,
+ OperandValueKind Op2Info) const {
+ return PrevTTI->getArithmeticInstrCost(Opcode, Ty, Op1Info, Op2Info);
}
unsigned TargetTransformInfo::getShuffleCost(ShuffleKind Kind, Type *Tp,
@@ -495,7 +497,8 @@
return 1;
}
- unsigned getArithmeticInstrCost(unsigned Opcode, Type *Ty) const {
+ unsigned getArithmeticInstrCost(unsigned Opcode, Type *Ty, OperandValueKind,
+ OperandValueKind) const {
return 1;
}