DAGCombiner: Merge store/loads when we have extload/truncstores
This is helps on architectures where i8,i16 are not legal but we have byte, and
short loads/stores. Allowing us to merge copies like the one below on ARM.
copy(char *a, char *b, int n) {
do {
int t0 = a[0];
int t1 = a[1];
b[0] = t0;
b[1] = t1;
radar://13536387
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178546 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index ff98a04..eb16095 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -7980,6 +7980,14 @@
EVT StoreTy = EVT::getIntegerVT(*DAG.getContext(), StoreBW);
if (TLI.isTypeLegal(StoreTy))
LastLegalType = i+1;
+ // Or check whether a truncstore is legal.
+ else if (TLI.getTypeAction(*DAG.getContext(), StoreTy) ==
+ TargetLowering::TypePromoteInteger) {
+ EVT LegalizedStoredValueTy =
+ TLI.getTypeToTransformTo(*DAG.getContext(), StoredVal.getValueType());
+ if (TLI.isTruncStoreLegal(LegalizedStoredValueTy, StoreTy))
+ LastLegalType = i+1;
+ }
// Find a legal type for the vector store.
EVT Ty = EVT::getVectorVT(*DAG.getContext(), MemVT, i+1);
@@ -8163,6 +8171,17 @@
StoreTy = EVT::getIntegerVT(*DAG.getContext(), StoreBW);
if (TLI.isTypeLegal(StoreTy))
LastLegalIntegerType = i + 1;
+ // Or check whether a truncstore and extload is legal.
+ else if (TLI.getTypeAction(*DAG.getContext(), StoreTy) ==
+ TargetLowering::TypePromoteInteger) {
+ EVT LegalizedStoredValueTy =
+ TLI.getTypeToTransformTo(*DAG.getContext(), StoreTy);
+ if (TLI.isTruncStoreLegal(LegalizedStoredValueTy, StoreTy) &&
+ TLI.isLoadExtLegal(ISD::ZEXTLOAD, StoreTy) &&
+ TLI.isLoadExtLegal(ISD::SEXTLOAD, StoreTy) &&
+ TLI.isLoadExtLegal(ISD::EXTLOAD, StoreTy))
+ LastLegalIntegerType = i+1;
+ }
}
// Only use vector types if the vector type is larger than the integer type.