6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2026-04-21 08:17:40 +00:00
Code Issues Projects Releases Wiki Activity

Add support for branch weight metadata to MDBuilder and use it in various places.

Browse Source 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157515 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer
2012-05-26 13:59:43 +00:00
parent 9632f77f8d
commit 937338cf64
3 changed files with 45 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/Transforms/Utils/LowerExpectIntrinsic.cpp
+17 -25
View File
@@ -23,6 +23,7 @@
#include "llvm/Transforms/Scalar.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/MDBuilder.h"
#include "llvm/ADT/Statistic.h"
#include <vector>
@@ -70,24 +71,18 @@ bool LowerExpectIntrinsic::HandleSwitchExpect(SwitchInst *SI) {
if (!ExpectedValue)
return false;
LLVMContext &Context = CI->getContext();
Type *Int32Ty = Type::getInt32Ty(Context);
SwitchInst::CaseIt Case = SI->findCaseValue(ExpectedValue);
std::vector<Value *> Vec;
unsigned n = SI->getNumCases();
Vec.resize(n + 1 + 1); // +1 for MDString and +1 for default case
unsigned n = SI->getNumCases(); // +1 for default case.
std::vector<uint32_t> Weights(n + 1);
Vec[0] = MDString::get(Context, "branch_weights");
Vec[1] = ConstantInt::get(Int32Ty, Case == SI->case_default() ?
LikelyBranchWeight : UnlikelyBranchWeight);
for (unsigned i = 0; i < n; ++i) {
Vec[i + 1 + 1] = ConstantInt::get(Int32Ty, i == Case.getCaseIndex() ?
LikelyBranchWeight : UnlikelyBranchWeight);
}
Weights[0] = Case == SI->case_default() ? LikelyBranchWeight
: UnlikelyBranchWeight;
for (unsigned i = 0; i != n; ++i)
Weights[i + 1] = i == Case.getCaseIndex() ? LikelyBranchWeight
: UnlikelyBranchWeight;
MDNode *WeightsNode = llvm::MDNode::get(Context, Vec);
SI->setMetadata(LLVMContext::MD_prof, WeightsNode);
SI->setMetadata(LLVMContext::MD_prof,
MDBuilder(CI->getContext()).createBranchWeights(Weights));
SI->setCondition(ArgValue);
return true;
@@ -120,20 +115,17 @@ bool LowerExpectIntrinsic::HandleIfExpect(BranchInst *BI) {
if (!ExpectedValue)
return false;
LLVMContext &Context = CI->getContext();
Type *Int32Ty = Type::getInt32Ty(Context);
bool Likely = ExpectedValue->isOne();
MDBuilder MDB(CI->getContext());
MDNode *Node;
// If expect value is equal to 1 it means that we are more likely to take
// branch 0, in other case more likely is branch 1.
Value *Ops[] = {
MDString::get(Context, "branch_weights"),
ConstantInt::get(Int32Ty, Likely ? LikelyBranchWeight : UnlikelyBranchWeight),
ConstantInt::get(Int32Ty, Likely ? UnlikelyBranchWeight : LikelyBranchWeight)
};
if (ExpectedValue->isOne())
Node = MDB.createBranchWeights(LikelyBranchWeight, UnlikelyBranchWeight);
else
Node = MDB.createBranchWeights(UnlikelyBranchWeight, LikelyBranchWeight);
MDNode *WeightsNode = MDNode::get(Context, Ops);
BI->setMetadata(LLVMContext::MD_prof, WeightsNode);
BI->setMetadata(LLVMContext::MD_prof, Node);
CmpI->setOperand(0, ArgValue);
return true;