#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,
return RegMap->createVirtualRegister(TLI.getRegClassFor(VT));
}
+void SelectionDAGISel::getAnalysisUsage(AnalysisUsage &AU) const {
+ if (!SplitPHICritEdges)
+ AU.setPreservesAll();
+}
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)