Sync upstream to r102410.
Re-turn on sdk.
Change-Id: I91a890863989a67243b4d2dfd1ae09b843ebaeaf
diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp
index e47ba7c..ef489dc 100644
--- a/lib/CodeGen/MachineSink.cpp
+++ b/lib/CodeGen/MachineSink.cpp
@@ -20,6 +20,7 @@
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/MachineDominators.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
@@ -37,6 +38,7 @@
const TargetRegisterInfo *TRI;
MachineRegisterInfo *RegInfo; // Machine register information
MachineDominatorTree *DT; // Machine dominator tree
+ MachineLoopInfo *LI;
AliasAnalysis *AA;
BitVector AllocatableSet; // Which physregs are allocatable?
@@ -51,7 +53,9 @@
MachineFunctionPass::getAnalysisUsage(AU);
AU.addRequired<AliasAnalysis>();
AU.addRequired<MachineDominatorTree>();
+ AU.addRequired<MachineLoopInfo>();
AU.addPreserved<MachineDominatorTree>();
+ AU.addPreserved<MachineLoopInfo>();
}
private:
bool ProcessBlock(MachineBasicBlock &MBB);
@@ -102,6 +106,7 @@
TRI = TM.getRegisterInfo();
RegInfo = &MF.getRegInfo();
DT = &getAnalysis<MachineDominatorTree>();
+ LI = &getAnalysis<MachineLoopInfo>();
AA = &getAnalysis<AliasAnalysis>();
AllocatableSet = TRI->getAllocatableSet(MF);
@@ -126,6 +131,11 @@
// Can't sink anything out of a block that has less than two successors.
if (MBB.succ_size() <= 1 || MBB.empty()) return false;
+ // Don't bother sinking code out of unreachable blocks. In addition to being
+ // unprofitable, it can also lead to infinite looping, because in an unreachable
+ // loop there may be nowhere to stop.
+ if (!DT->isReachableFromEntry(&MBB)) return false;
+
bool MadeChange = false;
// Walk the basic block bottom-up. Remember if we saw a store.
@@ -271,8 +281,29 @@
// but for now we just punt.
// FIXME: Split critical edges if not backedges.
if (SuccToSinkTo->pred_size() > 1) {
- DEBUG(dbgs() << " *** PUNTING: Critical edge found\n");
- return false;
+ // We cannot sink a load across a critical edge - there may be stores in
+ // other code paths.
+ bool store = true;
+ if (!MI->isSafeToMove(TII, AA, store)) {
+ DEBUG(dbgs() << " *** PUNTING: Wont sink load along critical edge.\n");
+ return false;
+ }
+
+ // We don't want to sink across a critical edge if we don't dominate the
+ // successor. We could be introducing calculations to new code paths.
+ if (!DT->dominates(ParentBlock, SuccToSinkTo)) {
+ DEBUG(dbgs() << " *** PUNTING: Critical edge found\n");
+ return false;
+ }
+
+ // Don't sink instructions into a loop.
+ if (LI->isLoopHeader(SuccToSinkTo)) {
+ DEBUG(dbgs() << " *** PUNTING: Loop header found\n");
+ return false;
+ }
+
+ // Otherwise we are OK with sinking along a critical edge.
+ DEBUG(dbgs() << "Sinking along critical edge.\n");
}
// Determine where to insert into. Skip phi nodes.