From c9721935835b1608f1cc0d82f852aa4d2cb39a0d Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev@redking.me.uk>
Date: Wed, 10 Jul 2019 11:26:57 +0000
Subject: [PATCH] [X86] EltsFromConsecutiveLoads - store Loads on a per-element
 basis. NFCI.

Cache the LoadSDNode nodes so we can easily map to/from the element index instead of packing them together - this will be useful for future patches for PR16739 etc.

llvm-svn: 365620
---
 llvm/lib/Target/X86/X86ISelLowering.cpp | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 6fee0bb87646..1040cc6ae36e 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -7517,6 +7517,8 @@ static SDValue EltsFromConsecutiveLoads(EVT VT, ArrayRef<SDValue> Elts,
   APInt ZeroMask = APInt::getNullValue(NumElems);
   APInt UndefMask = APInt::getNullValue(NumElems);
 
+  SmallVector<LoadSDNode*, 8> Loads(NumElems, nullptr);
+
   // For each element in the initializer, see if we've found a load, zero or an
   // undef.
   for (unsigned i = 0; i < NumElems; ++i) {
@@ -7529,6 +7531,7 @@ static SDValue EltsFromConsecutiveLoads(EVT VT, ArrayRef<SDValue> Elts,
     else if (X86::isZeroNode(Elt) || ISD::isBuildVectorAllZeros(Elt.getNode()))
       ZeroMask.setBit(i);
     else if (ISD::isNON_EXTLoad(Elt.getNode())) {
+      Loads[i] = cast<LoadSDNode>(Elt);
       LoadMask.setBit(i);
       LastLoadedElt = i;
       // Each loaded element must be the correct fractional portion of the
@@ -7554,7 +7557,7 @@ static SDValue EltsFromConsecutiveLoads(EVT VT, ArrayRef<SDValue> Elts,
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
   int FirstLoadedElt = LoadMask.countTrailingZeros();
   SDValue EltBase = peekThroughBitcasts(Elts[FirstLoadedElt]);
-  LoadSDNode *LDBase = cast<LoadSDNode>(EltBase);
+  LoadSDNode *LDBase = Loads[FirstLoadedElt];
   EVT LDBaseVT = EltBase.getValueType();
 
   // Consecutive loads can contain UNDEFS but not ZERO elements.
@@ -7565,7 +7568,7 @@ static SDValue EltsFromConsecutiveLoads(EVT VT, ArrayRef<SDValue> Elts,
   for (int i = FirstLoadedElt + 1; i <= LastLoadedElt; ++i) {
     if (LoadMask[i]) {
       SDValue Elt = peekThroughBitcasts(Elts[i]);
-      LoadSDNode *LD = cast<LoadSDNode>(Elt);
+      LoadSDNode* LD = Loads[i];
       if (!DAG.areNonVolatileConsecutiveLoads(
               LD, LDBase, Elt.getValueType().getStoreSizeInBits() / 8,
               i - FirstLoadedElt)) {
@@ -7578,11 +7581,6 @@ static SDValue EltsFromConsecutiveLoads(EVT VT, ArrayRef<SDValue> Elts,
     }
   }
 
-  SmallVector<LoadSDNode *, 8> Loads;
-  for (int i = FirstLoadedElt; i <= LastLoadedElt; ++i)
-    if (LoadMask[i])
-      Loads.push_back(cast<LoadSDNode>(peekThroughBitcasts(Elts[i])));
-
   auto CreateLoad = [&DAG, &DL, &Loads](EVT VT, LoadSDNode *LDBase) {
     auto MMOFlags = LDBase->getMemOperand()->getFlags();
     assert(!(MMOFlags & MachineMemOperand::MOVolatile) &&
@@ -7591,7 +7589,8 @@ static SDValue EltsFromConsecutiveLoads(EVT VT, ArrayRef<SDValue> Elts,
         DAG.getLoad(VT, DL, LDBase->getChain(), LDBase->getBasePtr(),
                     LDBase->getPointerInfo(), LDBase->getAlignment(), MMOFlags);
     for (auto *LD : Loads)
-      DAG.makeEquivalentMemoryOrdering(LD, NewLd);
+      if (LD)
+        DAG.makeEquivalentMemoryOrdering(LD, NewLd);
     return NewLd;
   };
 
@@ -7682,7 +7681,8 @@ static SDValue EltsFromConsecutiveLoads(EVT VT, ArrayRef<SDValue> Elts,
                                   LDBase->getAlignment(),
                                   MachineMemOperand::MOLoad);
       for (auto *LD : Loads)
-        DAG.makeEquivalentMemoryOrdering(LD, ResNode);
+        if (LD)
+          DAG.makeEquivalentMemoryOrdering(LD, ResNode);
       return DAG.getBitcast(VT, ResNode);
     }
   }