[foldMemoryOperand()] Pass LiveIntervals to enable liveness check.
SystemZ (and probably other targets as well) can fold a memory operand
by changing the opcode into a new instruction that as a side-effect
also clobbers the CC-reg.
In order to do this, liveness of that reg must first be checked. When
LIS is passed, getRegUnit() can be called on it and the right
LiveRange is computed on demand.
Reviewed by Matthias Braun.
http://reviews.llvm.org/D19861
llvm-svn: 269026
diff --git a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
index 3938db2..fa824d0 100644
--- a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
@@ -15,6 +15,7 @@
#include "SystemZInstrBuilder.h"
#include "SystemZTargetMachine.h"
#include "llvm/CodeGen/LiveVariables.h"
+#include "llvm/CodeGen/LiveIntervalAnalysis.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
using namespace llvm;
@@ -846,31 +847,42 @@
MachineInstr *SystemZInstrInfo::foldMemoryOperandImpl(
MachineFunction &MF, MachineInstr *MI, ArrayRef<unsigned> Ops,
- MachineBasicBlock::iterator InsertPt, int FrameIndex) const {
+ MachineBasicBlock::iterator InsertPt, int FrameIndex,
+ LiveIntervals *LIS) const {
+ const TargetRegisterInfo *TRI = MF.getSubtarget().getRegisterInfo();
const MachineFrameInfo *MFI = MF.getFrameInfo();
unsigned Size = MFI->getObjectSize(FrameIndex);
unsigned Opcode = MI->getOpcode();
-// XXX This is an introduction of a CC def and is illegal! Reactivate
-// with a check of liveness of CC reg.
-#if 0
if (Ops.size() == 2 && Ops[0] == 0 && Ops[1] == 1) {
- if ((Opcode == SystemZ::LA || Opcode == SystemZ::LAY) &&
+ if (LIS != nullptr &&
+ (Opcode == SystemZ::LA || Opcode == SystemZ::LAY) &&
isInt<8>(MI->getOperand(2).getImm()) &&
!MI->getOperand(3).getReg()) {
- // LA(Y) %reg, CONST(%reg) -> AGSI %mem, CONST
- MachineInstr *BuiltMI =
- BuildMI(*InsertPt->getParent(), InsertPt, MI->getDebugLoc(),
- get(SystemZ::AGSI))
+
+ // Check CC liveness, since new instruction introduces a dead
+ // def of CC.
+ MCRegUnitIterator CCUnit(SystemZ::CC, TRI);
+ LiveRange &CCLiveRange = LIS->getRegUnit(*CCUnit);
+ ++CCUnit;
+ assert (!CCUnit.isValid() && "CC only has one reg unit.");
+ SlotIndex MISlot =
+ LIS->getSlotIndexes()->getInstructionIndex(*MI).getRegSlot();
+ if (!CCLiveRange.liveAt(MISlot)) {
+ // LA(Y) %reg, CONST(%reg) -> AGSI %mem, CONST
+ MachineInstr *BuiltMI =
+ BuildMI(*InsertPt->getParent(), InsertPt, MI->getDebugLoc(),
+ get(SystemZ::AGSI))
.addFrameIndex(FrameIndex)
.addImm(0)
.addImm(MI->getOperand(2).getImm());
- BuiltMI->findRegisterDefOperand(SystemZ::CC)->setIsDead(true);
- return BuiltMI;
+ BuiltMI->findRegisterDefOperand(SystemZ::CC)->setIsDead(true);
+ CCLiveRange.createDeadDef(MISlot, LIS->getVNInfoAllocator());
+ return BuiltMI;
+ }
}
return nullptr;
}
-#endif
// All other cases require a single operand.
if (Ops.size() != 1)
@@ -992,7 +1004,8 @@
MachineInstr *SystemZInstrInfo::foldMemoryOperandImpl(
MachineFunction &MF, MachineInstr *MI, ArrayRef<unsigned> Ops,
- MachineBasicBlock::iterator InsertPt, MachineInstr *LoadMI) const {
+ MachineBasicBlock::iterator InsertPt, MachineInstr *LoadMI,
+ LiveIntervals *LIS) const {
return nullptr;
}