[PATCH] D71442: [X86] Check if source elements are not structures before using a uniform base for the Gather/Scatter intrinsic.

[LuoYuanke via Phabricator via llvm-commits]

LuoYuanke added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp:4375
+  if (GTI.isStruct())
+    return false;
+
----------------
Maybe we can calculate the offset for struct if the index is constant.

    APInt Offset(DL.getIndexTypeSizeInBits(GEP->getType()), 0);
    if (!GEP->accumulateConstantOffset(DL, Offset))
      return false;
    Index = DAG.getTargetConstant(Offset, SDB->getCurSDLoc(), TLI.getPointerTy(DL));
    Scale = DAG.getTargetConstant(1, SDB->getCurSDLoc(), TLI.getPointerTy(DL));

Also recognize zeroinitializer in accumulateConstantOffset().

--- a/llvm/lib/IR/Operator.cpp
+++ b/llvm/lib/IR/Operator.cpp
@@ -39,6 +39,9 @@ bool GEPOperator::accumulateConstantOffset(const DataLayout &DL,

   for (gep_type_iterator GTI = gep_type_begin(this), GTE = gep_type_end(this);
        GTI != GTE; ++GTI) {
+
+    if (isa<ConstantAggregateZero>(GTI.getOperand()))
+      continue;
     ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand());
     if (!OpC)
       return false;



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71442/new/

https://reviews.llvm.org/D71442