#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
-#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
}
bool MachineSinking::ProcessBlock(MachineBasicBlock &MBB) {
- bool MadeChange = false;
-
// Can't sink anything out of a block that has less than two successors.
- if (MBB.succ_size() <= 1) return false;
-
+ if (MBB.succ_size() <= 1 || MBB.empty()) return false;
+
+ bool MadeChange = false;
+
// Walk the basic block bottom-up. Remember if we saw a store.
- bool SawStore = false;
- for (MachineBasicBlock::iterator I = MBB.end(); I != MBB.begin(); ){
- MachineBasicBlock::iterator LastIt = I;
- if (SinkInstruction(--I, SawStore)) {
- I = LastIt;
- ++NumSunk;
- }
- }
+ MachineBasicBlock::iterator I = MBB.end();
+ --I;
+ bool ProcessedBegin, SawStore = false;
+ do {
+ MachineInstr *MI = I; // The instruction to sink.
+
+ // Predecrement I (if it's not begin) so that it isn't invalidated by
+ // sinking.
+ ProcessedBegin = I == MBB.begin();
+ if (!ProcessedBegin)
+ --I;
+
+ if (SinkInstruction(MI, SawStore))
+ ++NumSunk, MadeChange = true;
+
+ // If we just processed the first instruction in the block, we're done.
+ } while (!ProcessedBegin);
return MadeChange;
}
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
- if (!MO.isRegister()) continue; // Ignore non-register operands.
+ if (!MO.isReg()) continue; // Ignore non-register operands.
unsigned Reg = MO.getReg();
if (Reg == 0) continue;
} else {
// Virtual register uses are always safe to sink.
if (MO.isUse()) continue;
+
+ // If it's not safe to move defs of the register class, then abort.
+ if (!TII->isSafeToMoveRegClassDefs(RegInfo->getRegClass(Reg)))
+ return false;
// FIXME: This picks a successor to sink into based on having one
// successor that dominates all the uses. However, there are cases where
// If there are no outputs, it must have side-effects.
if (SuccToSinkTo == 0)
return false;
+
+ // It's not safe to sink instructions to EH landing pad. Control flow into
+ // landing pad is implicitly defined.
+ if (SuccToSinkTo->isLandingPad())
+ return false;
+
+ // If is not possible to sink an instruction into its own block. This can
+ // happen with loops.
+ if (MI->getParent() == SuccToSinkTo)
+ return false;
DEBUG(cerr << "Sink instr " << *MI);
DEBUG(cerr << "to block " << *SuccToSinkTo);