Make sure no loads resulting from load->switch DAGCombine are marked invariant

Currently when DAGCombine converts loads feeding a switch into a switch of
addresses feeding a load the new load inherits the isInvariant flag of the left
side. This is incorrect since invariant loads can be reordered in cases where it
is illegal to reoarder normal loads.

This patch adds an isInvariant parameter to getExtLoad() and updates all call
sites to pass in the data if they have it or false if they don't. It also
changes the DAGCombine to use that data to make the right decision when
creating the new load.

llvm-svn: 214449

1 files changed, 24 insertions, 18 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 6a3402a9a6f..ba2ba9c71ce 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -298,7 +298,7 @@ SelectionDAGLegalize::ExpandConstantFP(ConstantFPSDNode *CFP, bool UseCP) {
       DAG.getExtLoad(ISD::EXTLOAD, dl, OrigVT,
                      DAG.getEntryNode(),
                      CPIdx, MachinePointerInfo::getConstantPool(),
-                     VT, false, false, Alignment);
+                     VT, false, false, false, Alignment);
     return Result;
   }
   SDValue Result =
@@ -384,7 +384,7 @@ static void ExpandUnalignedStore(StoreSDNode *ST, SelectionDAG &DAG,
     // Load from the stack slot.
     SDValue Load = DAG.getExtLoad(ISD::EXTLOAD, dl, RegVT, Store, StackPtr,
                                   MachinePointerInfo(),
-                                  MemVT, false, false, 0);
+                                  MemVT, false, false, false, 0);
 
     Stores.push_back(DAG.getTruncStore(Load.getValue(1), dl, Load, Ptr,
                                        ST->getPointerInfo()
@@ -501,6 +501,7 @@ ExpandUnalignedLoad(LoadSDNode *LD, SelectionDAG &DAG,
                                   LD->getPointerInfo().getWithOffset(Offset),
                                   MemVT, LD->isVolatile(),
                                   LD->isNonTemporal(),
+                                  LD->isInvariant(),
                                   MinAlign(LD->getAlignment(), Offset),
                                   LD->getAAInfo());
     // Follow the load with a store to the stack slot.  Remember the store.
@@ -515,7 +516,8 @@ ExpandUnalignedLoad(LoadSDNode *LD, SelectionDAG &DAG,
 
     // Finally, perform the original load only redirected to the stack slot.
     Load = DAG.getExtLoad(LD->getExtensionType(), dl, VT, TF, StackBase,
-                          MachinePointerInfo(), LoadedVT, false, false, 0);
+                          MachinePointerInfo(), LoadedVT, false,false, false,
+                          0);
 
     // Callers expect a MERGE_VALUES node.
     ValResult = Load;
@@ -545,25 +547,27 @@ ExpandUnalignedLoad(LoadSDNode *LD, SelectionDAG &DAG,
   if (TLI.isLittleEndian()) {
     Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, VT, Chain, Ptr, LD->getPointerInfo(),
                         NewLoadedVT, LD->isVolatile(),
-                        LD->isNonTemporal(), Alignment, LD->getAAInfo());
+                        LD->isNonTemporal(), LD->isInvariant(), Alignment,
+                        LD->getAAInfo());
     Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
                       DAG.getConstant(IncrementSize, Ptr.getValueType()));
     Hi = DAG.getExtLoad(HiExtType, dl, VT, Chain, Ptr,
                         LD->getPointerInfo().getWithOffset(IncrementSize),
                         NewLoadedVT, LD->isVolatile(),
-                        LD->isNonTemporal(), MinAlign(Alignment, IncrementSize),
-                        LD->getAAInfo());
+                        LD->isNonTemporal(),LD->isInvariant(),
+                        MinAlign(Alignment, IncrementSize), LD->getAAInfo());
   } else {
     Hi = DAG.getExtLoad(HiExtType, dl, VT, Chain, Ptr, LD->getPointerInfo(),
                         NewLoadedVT, LD->isVolatile(),
-                        LD->isNonTemporal(), Alignment, LD->getAAInfo());
+                        LD->isNonTemporal(), LD->isInvariant(), Alignment,
+                        LD->getAAInfo());
     Ptr = DAG.getNode(ISD::ADD, dl, Ptr.getValueType(), Ptr,
                       DAG.getConstant(IncrementSize, Ptr.getValueType()));
     Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, VT, Chain, Ptr,
                         LD->getPointerInfo().getWithOffset(IncrementSize),
                         NewLoadedVT, LD->isVolatile(),
-                        LD->isNonTemporal(), MinAlign(Alignment, IncrementSize),
-                        LD->getAAInfo());
+                        LD->isNonTemporal(), LD->isInvariant(),
+                        MinAlign(Alignment, IncrementSize), LD->getAAInfo());
   }
 
   // aggregate the two parts
@@ -952,6 +956,7 @@ void SelectionDAGLegalize::LegalizeLoadOps(SDNode *Node) {
   unsigned Alignment = LD->getAlignment();
   bool isVolatile = LD->isVolatile();
   bool isNonTemporal = LD->isNonTemporal();
+  bool isInvariant = LD->isInvariant();
   AAMDNodes AAInfo = LD->getAAInfo();
 
   if (SrcWidth != SrcVT.getStoreSizeInBits() &&
@@ -979,7 +984,8 @@ void SelectionDAGLegalize::LegalizeLoadOps(SDNode *Node) {
     SDValue Result =
       DAG.getExtLoad(NewExtType, dl, Node->getValueType(0),
                      Chain, Ptr, LD->getPointerInfo(),
-                     NVT, isVolatile, isNonTemporal, Alignment, AAInfo);
+                     NVT, isVolatile, isNonTemporal, isInvariant, Alignment,
+                     AAInfo);
 
     Ch = Result.getValue(1); // The chain.
 
@@ -1016,7 +1022,7 @@ void SelectionDAGLegalize::LegalizeLoadOps(SDNode *Node) {
       Lo = DAG.getExtLoad(ISD::ZEXTLOAD, dl, Node->getValueType(0),
                           Chain, Ptr,
                           LD->getPointerInfo(), RoundVT, isVolatile,
-                          isNonTemporal, Alignment, AAInfo);
+                          isNonTemporal, isInvariant, Alignment, AAInfo);
 
       // Load the remaining ExtraWidth bits.
       IncrementSize = RoundWidth / 8;
@@ -1024,7 +1030,7 @@ void SelectionDAGLegalize::LegalizeLoadOps(SDNode *Node) {
                          DAG.getConstant(IncrementSize, Ptr.getValueType()));
       Hi = DAG.getExtLoad(ExtType, dl, Node->getValueType(0), Chain, Ptr,
                           LD->getPointerInfo().getWithOffset(IncrementSize),
-                          ExtraVT, isVolatile, isNonTemporal,
+                          ExtraVT, isVolatile, isNonTemporal, isInvariant,
                           MinAlign(Alignment, IncrementSize), AAInfo);
 
       // Build a factor node to remember that this load is independent of
@@ -1045,7 +1051,7 @@ void SelectionDAGLegalize::LegalizeLoadOps(SDNode *Node) {
       // Load the top RoundWidth bits.
       Hi = DAG.getExtLoad(ExtType, dl, Node->getValueType(0), Chain, Ptr,
                           LD->getPointerInfo(), RoundVT, isVolatile,
-                          isNonTemporal, Alignment, AAInfo);
+                          isNonTemporal, isInvariant, Alignment, AAInfo);
 
       // Load the remaining ExtraWidth bits.
       IncrementSize = RoundWidth / 8;
@@ -1054,7 +1060,7 @@ void SelectionDAGLegalize::LegalizeLoadOps(SDNode *Node) {
       Lo = DAG.getExtLoad(ISD::ZEXTLOAD,
                           dl, Node->getValueType(0), Chain, Ptr,
                           LD->getPointerInfo().getWithOffset(IncrementSize),
-                          ExtraVT, isVolatile, isNonTemporal,
+                          ExtraVT, isVolatile, isNonTemporal, isInvariant,
                           MinAlign(Alignment, IncrementSize), AAInfo);
 
       // Build a factor node to remember that this load is independent of
@@ -1467,7 +1473,7 @@ SDValue SelectionDAGLegalize::ExpandExtractFromVectorThroughStack(SDValue Op) {
   return DAG.getExtLoad(ISD::EXTLOAD, dl, Op.getValueType(), Ch, StackPtr,
                         MachinePointerInfo(),
                         Vec.getValueType().getVectorElementType(),
-                        false, false, 0);
+                        false, false, false, 0);
 }
 
 SDValue SelectionDAGLegalize::ExpandInsertToVectorThroughStack(SDValue Op) {
@@ -1816,7 +1822,7 @@ SDValue SelectionDAGLegalize::EmitStackConvert(SDValue SrcOp,
 
   assert(SlotSize < DestSize && "Unknown extension!");
   return DAG.getExtLoad(ISD::EXTLOAD, dl, DestVT, Store, FIPtr,
-                        PtrInfo, SlotVT, false, false, DestAlign);
+                        PtrInfo, SlotVT, false, false, false, DestAlign);
 }
 
 SDValue SelectionDAGLegalize::ExpandSCALAR_TO_VECTOR(SDNode *Node) {
@@ -2599,7 +2605,7 @@ SDValue SelectionDAGLegalize::ExpandLegalINT_TO_FP(bool isSigned,
     SDValue Load = DAG.getExtLoad(ISD::EXTLOAD, dl, DestVT,
                                   DAG.getEntryNode(), CPIdx,
                                   MachinePointerInfo::getConstantPool(),
-                                  MVT::f32, false, false, Alignment);
+                                  MVT::f32, false, false, false, Alignment);
     HandleSDNode Handle(Load);
     LegalizeOp(Load.getNode());
     FudgeInReg = Handle.getValue();
@@ -3887,7 +3893,7 @@ void SelectionDAGLegalize::ExpandNode(SDNode *Node) {
     EVT MemVT = EVT::getIntegerVT(*DAG.getContext(), EntrySize * 8);
     SDValue LD = DAG.getExtLoad(ISD::SEXTLOAD, dl, PTy, Chain, Addr,
                                 MachinePointerInfo::getJumpTable(), MemVT,
-                                false, false, 0);
+                                false, false, false, 0);
     Addr = LD;
     if (TM.getRelocationModel() == Reloc::PIC_) {
       // For PIC, the sequence is: