- Two-address pass should not assume unfolding is always successful.
- X86 unfolding should check if the instructions being unfolded has memoperands.
If there is no memoperands, then it must assume conservative alignment. If this
would introduce an expensive sse unaligned load / store, then unfoldMemoryOperand
etc. should not unfold the instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107509 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp
index caa6233..c1d66cb 100644
--- a/lib/Target/X86/X86InstrInfo.cpp
+++ b/lib/Target/X86/X86InstrInfo.cpp
@@ -2159,7 +2159,7 @@
MachineInstr::mmo_iterator MMOBegin,
MachineInstr::mmo_iterator MMOEnd,
SmallVectorImpl<MachineInstr*> &NewMIs) const {
- bool isAligned = (*MMOBegin)->getAlignment() >= 16;
+ bool isAligned = *MMOBegin && (*MMOBegin)->getAlignment() >= 16;
unsigned Opc = getStoreRegOpcode(SrcReg, RC, isAligned, TM);
DebugLoc DL;
MachineInstrBuilder MIB = BuildMI(MF, DL, get(Opc));
@@ -2189,7 +2189,7 @@
MachineInstr::mmo_iterator MMOBegin,
MachineInstr::mmo_iterator MMOEnd,
SmallVectorImpl<MachineInstr*> &NewMIs) const {
- bool isAligned = (*MMOBegin)->getAlignment() >= 16;
+ bool isAligned = *MMOBegin && (*MMOBegin)->getAlignment() >= 16;
unsigned Opc = getLoadRegOpcode(DestReg, RC, isAligned, TM);
DebugLoc DL;
MachineInstrBuilder MIB = BuildMI(MF, DL, get(Opc), DestReg);
@@ -2693,6 +2693,13 @@
const TargetInstrDesc &TID = get(Opc);
const TargetOperandInfo &TOI = TID.OpInfo[Index];
const TargetRegisterClass *RC = TOI.getRegClass(&RI);
+ if (!MI->hasOneMemOperand() &&
+ RC == &X86::VR128RegClass &&
+ !TM.getSubtarget<X86Subtarget>().isUnalignedMemAccessFast())
+ // Without memoperands, loadRegFromAddr and storeRegToStackSlot will
+ // conservatively assume the address is unaligned. That's bad for
+ // performance.
+ return false;
SmallVector<MachineOperand, X86AddrNumOperands> AddrOps;
SmallVector<MachineOperand,2> BeforeOps;
SmallVector<MachineOperand,2> AfterOps;
@@ -2834,7 +2841,12 @@
MachineInstr::mmo_iterator> MMOs =
MF.extractLoadMemRefs(cast<MachineSDNode>(N)->memoperands_begin(),
cast<MachineSDNode>(N)->memoperands_end());
- bool isAligned = (*MMOs.first)->getAlignment() >= 16;
+ if (!(*MMOs.first) &&
+ RC == &X86::VR128RegClass &&
+ !TM.getSubtarget<X86Subtarget>().isUnalignedMemAccessFast())
+ // Do not introduce a slow unaligned load.
+ return false;
+ bool isAligned = (*MMOs.first) && (*MMOs.first)->getAlignment() >= 16;
Load = DAG.getMachineNode(getLoadRegOpcode(0, RC, isAligned, TM), dl,
VT, MVT::Other, &AddrOps[0], AddrOps.size());
NewNodes.push_back(Load);
@@ -2871,7 +2883,12 @@
MachineInstr::mmo_iterator> MMOs =
MF.extractStoreMemRefs(cast<MachineSDNode>(N)->memoperands_begin(),
cast<MachineSDNode>(N)->memoperands_end());
- bool isAligned = (*MMOs.first)->getAlignment() >= 16;
+ if (!(*MMOs.first) &&
+ RC == &X86::VR128RegClass &&
+ !TM.getSubtarget<X86Subtarget>().isUnalignedMemAccessFast())
+ // Do not introduce a slow unaligned store.
+ return false;
+ bool isAligned = (*MMOs.first) && (*MMOs.first)->getAlignment() >= 16;
SDNode *Store = DAG.getMachineNode(getStoreRegOpcode(0, DstRC,
isAligned, TM),
dl, MVT::Other,