[llvm] r358900 - [PGO/SamplePGO][NFC] Move the function updateProfWeight from Instruction
Wei Mi via llvm-commits
llvm-commits at lists.llvm.org
Mon Apr 22 10:04:51 PDT 2019
Author: wmi
Date: Mon Apr 22 10:04:51 2019
New Revision: 358900
URL: http://llvm.org/viewvc/llvm-project?rev=358900&view=rev
Log:
[PGO/SamplePGO][NFC] Move the function updateProfWeight from Instruction
to CallInst.
The issue was raised here: https://reviews.llvm.org/D60903#1472783
The function Instruction::updateProfWeight is only used for CallInst in
profile update. From the current interface, it is very easy to think that
the function can also be used for branch instruction. However, Branch
instruction does't need the scaling the function provides for
branch_weights and VP (value profile), in addition, scaling may introduce
inaccuracy for branch probablity.
The patch moves the function updateProfWeight from Instruction class to
CallInst to remove the confusion. The patch also changes the scaling of
branch_weights from a loop to a block because we know that ProfileData
for branch_weights of CallInst will only have two operands at most.
Differential Revision: https://reviews.llvm.org/D60911
Modified:
llvm/trunk/include/llvm/IR/Instruction.h
llvm/trunk/include/llvm/IR/Instructions.h
llvm/trunk/lib/IR/Instruction.cpp
llvm/trunk/lib/IR/Instructions.cpp
Modified: llvm/trunk/include/llvm/IR/Instruction.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/Instruction.h?rev=358900&r1=358899&r2=358900&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/Instruction.h (original)
+++ llvm/trunk/include/llvm/IR/Instruction.h Mon Apr 22 10:04:51 2019
@@ -311,9 +311,6 @@ public:
/// Returns false if no metadata was found.
bool extractProfTotalWeight(uint64_t &TotalVal) const;
- /// Updates branch_weights metadata by scaling it by \p S / \p T.
- void updateProfWeight(uint64_t S, uint64_t T);
-
/// Sets the branch_weights metadata to \p W for CallInst.
void setProfWeight(uint64_t W);
Modified: llvm/trunk/include/llvm/IR/Instructions.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/Instructions.h?rev=358900&r1=358899&r2=358900&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/Instructions.h (original)
+++ llvm/trunk/include/llvm/IR/Instructions.h Mon Apr 22 10:04:51 2019
@@ -1730,6 +1730,9 @@ public:
return isa<Instruction>(V) && classof(cast<Instruction>(V));
}
+ /// Updates profile metadata by scaling it by \p S / \p T.
+ void updateProfWeight(uint64_t S, uint64_t T);
+
private:
// Shadow Instruction::setInstructionSubclassData with a private forwarding
// method so that subclasses cannot accidentally use it.
Modified: llvm/trunk/lib/IR/Instruction.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Instruction.cpp?rev=358900&r1=358899&r2=358900&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Instruction.cpp (original)
+++ llvm/trunk/lib/IR/Instruction.cpp Mon Apr 22 10:04:51 2019
@@ -735,49 +735,6 @@ Instruction *Instruction::clone() const
return New;
}
-void Instruction::updateProfWeight(uint64_t S, uint64_t T) {
- auto *ProfileData = getMetadata(LLVMContext::MD_prof);
- if (ProfileData == nullptr)
- return;
-
- auto *ProfDataName = dyn_cast<MDString>(ProfileData->getOperand(0));
- if (!ProfDataName || (!ProfDataName->getString().equals("branch_weights") &&
- !ProfDataName->getString().equals("VP")))
- return;
-
- MDBuilder MDB(getContext());
- SmallVector<Metadata *, 3> Vals;
- Vals.push_back(ProfileData->getOperand(0));
- APInt APS(128, S), APT(128, T);
- if (ProfDataName->getString().equals("branch_weights"))
- for (unsigned i = 1; i < ProfileData->getNumOperands(); i++) {
- // Using APInt::div may be expensive, but most cases should fit 64 bits.
- APInt Val(128,
- mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(i))
- ->getValue()
- .getZExtValue());
- Val *= APS;
- Vals.push_back(MDB.createConstant(
- ConstantInt::get(Type::getInt64Ty(getContext()),
- Val.udiv(APT).getLimitedValue())));
- }
- else if (ProfDataName->getString().equals("VP"))
- for (unsigned i = 1; i < ProfileData->getNumOperands(); i += 2) {
- // The first value is the key of the value profile, which will not change.
- Vals.push_back(ProfileData->getOperand(i));
- // Using APInt::div may be expensive, but most cases should fit 64 bits.
- APInt Val(128,
- mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(i + 1))
- ->getValue()
- .getZExtValue());
- Val *= APS;
- Vals.push_back(MDB.createConstant(
- ConstantInt::get(Type::getInt64Ty(getContext()),
- Val.udiv(APT).getLimitedValue())));
- }
- setMetadata(LLVMContext::MD_prof, MDNode::get(getContext(), Vals));
-}
-
void Instruction::setProfWeight(uint64_t W) {
assert(isa<CallBase>(this) &&
"Can only set weights for call like instructions");
Modified: llvm/trunk/lib/IR/Instructions.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Instructions.cpp?rev=358900&r1=358899&r2=358900&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Instructions.cpp (original)
+++ llvm/trunk/lib/IR/Instructions.cpp Mon Apr 22 10:04:51 2019
@@ -28,6 +28,7 @@
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
@@ -458,6 +459,49 @@ CallInst *CallInst::Create(CallInst *CI,
return NewCI;
}
+// Update profile weight for call instruction by scaling it using the ratio
+// of S/T. The meaning of "branch_weights" meta data for call instruction is
+// transfered to represent call count.
+void CallInst::updateProfWeight(uint64_t S, uint64_t T) {
+ auto *ProfileData = getMetadata(LLVMContext::MD_prof);
+ if (ProfileData == nullptr)
+ return;
+
+ auto *ProfDataName = dyn_cast<MDString>(ProfileData->getOperand(0));
+ if (!ProfDataName || (!ProfDataName->getString().equals("branch_weights") &&
+ !ProfDataName->getString().equals("VP")))
+ return;
+
+ MDBuilder MDB(getContext());
+ SmallVector<Metadata *, 3> Vals;
+ Vals.push_back(ProfileData->getOperand(0));
+ APInt APS(128, S), APT(128, T);
+ if (ProfDataName->getString().equals("branch_weights") &&
+ ProfileData->getNumOperands() > 0) {
+ // Using APInt::div may be expensive, but most cases should fit 64 bits.
+ APInt Val(128, mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(1))
+ ->getValue()
+ .getZExtValue());
+ Val *= APS;
+ Vals.push_back(MDB.createConstant(ConstantInt::get(
+ Type::getInt64Ty(getContext()), Val.udiv(APT).getLimitedValue())));
+ } else if (ProfDataName->getString().equals("VP"))
+ for (unsigned i = 1; i < ProfileData->getNumOperands(); i += 2) {
+ // The first value is the key of the value profile, which will not change.
+ Vals.push_back(ProfileData->getOperand(i));
+ // Using APInt::div may be expensive, but most cases should fit 64 bits.
+ APInt Val(128,
+ mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(i + 1))
+ ->getValue()
+ .getZExtValue());
+ Val *= APS;
+ Vals.push_back(MDB.createConstant(
+ ConstantInt::get(Type::getInt64Ty(getContext()),
+ Val.udiv(APT).getLimitedValue())));
+ }
+ setMetadata(LLVMContext::MD_prof, MDNode::get(getContext(), Vals));
+}
+
/// IsConstantOne - Return true only if val is constant int 1
static bool IsConstantOne(Value *val) {
assert(val && "IsConstantOne does not work with nullptr val");
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