RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-10-21 03:53:04 +02:00
Code Issues Projects Releases Wiki Activity

Add a new beta option for critical edge splitting, to avoid a problem that

Browse Source 
Nate noticed in yacr2 (and I know occurs in other places as well).

This is still rough, as the critical edge blocks are not intelligently placed
but is added to get some idea to see if this improves performance.

llvm-svn: 22825
This commit is contained in:
Chris Lattner 2005-08-17 06:37:43 +00:00
parent 969232d2ec
commit dbfcba7565
1 changed files with 23 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
View File

@ -29,12 +29,18 @@
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetLowering.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include <map>
#include <iostream>
using namespace llvm;
static cl::opt<bool>
SplitPHICritEdges("split-phi-constant-crit-edges", cl::Hidden,
cl::desc("Split critical edges for PHI values that are constants"));
#ifndef _NDEBUG
static cl::opt<bool>
ViewDAGs("view-isel-dags", cl::Hidden,
@ -959,6 +965,10 @@ unsigned SelectionDAGISel::MakeReg(MVT::ValueType VT) {
return RegMap->createVirtualRegister(TLI.getRegClassFor(VT));
}
void SelectionDAGISel::getAnalysisUsage(AnalysisUsage &AU) const {
if (!SplitPHICritEdges)
AU.setPreservesAll();
}
bool SelectionDAGISel::runOnFunction(Function &Fn) {
@ -966,6 +976,19 @@ bool SelectionDAGISel::runOnFunction(Function &Fn) {
RegMap = MF.getSSARegMap();
DEBUG(std::cerr << "\n\n\n=== " << Fn.getName() << "\n");
// First pass, split all critical edges for PHI nodes with incoming values
// that are constants, this way the load of the constant into a vreg will not
// be placed into MBBs that are used some other way.
if (SplitPHICritEdges)
for (Function::iterator BB = Fn.begin(), E = Fn.end(); BB != E; ++BB) {
PHINode *PN;
for (BasicBlock::iterator BBI = BB->begin();
(PN = dyn_cast<PHINode>(BBI)); ++BBI)
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
if (isa<Constant>(PN->getIncomingValue(i)))
SplitCriticalEdge(PN->getIncomingBlock(i), BB);
}
FunctionLoweringInfo FuncInfo(TLI, Fn, MF);
for (Function::iterator I = Fn.begin(), E = Fn.end(); I != E; ++I)