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
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 6426ee5..ff8fdf4 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -3990,7 +3990,7 @@
Value = DAG.getExtLoad(ISD::EXTLOAD, dl, NVT, Chain,
getMemBasePlusOffset(Src, SrcOff, dl, DAG),
SrcPtrInfo.getWithOffset(SrcOff), VT, isVol, false,
- MinAlign(SrcAlign, SrcOff));
+ false, MinAlign(SrcAlign, SrcOff));
Store = DAG.getTruncStore(Chain, dl, Value,
getMemBasePlusOffset(Dst, DstOff, dl, DAG),
DstPtrInfo.getWithOffset(DstOff), VT, isVol,
@@ -4746,11 +4746,12 @@
SDValue Chain, SDValue Ptr,
MachinePointerInfo PtrInfo, EVT MemVT,
bool isVolatile, bool isNonTemporal,
- unsigned Alignment, const AAMDNodes &AAInfo) {
+ bool isInvariant, unsigned Alignment,
+ const AAMDNodes &AAInfo) {
SDValue Undef = getUNDEF(Ptr.getValueType());
return getLoad(ISD::UNINDEXED, ExtType, VT, dl, Chain, Ptr, Undef,
- PtrInfo, MemVT, isVolatile, isNonTemporal, false, Alignment,
- AAInfo);
+ PtrInfo, MemVT, isVolatile, isNonTemporal, isInvariant,
+ Alignment, AAInfo);
}