move DAGCombiner's allowableAlignment() helper function into the TLI
Making allowableAlignment() more accessible was suggested as a predecessor patch
for D10662, so I've pulled it into TargetLowering. This let's us remove 4 instances
of duplicate logic in LegalizeDAG.
There's a subtle functional change in the implementation: the existing
allowableAlignment() code was using getPrefTypeAlignment() when checking
alignment with the DataLayout and assumed that was fast. In this implementation,
we use getABITypeAlignment() and assume that is fast. See the TODO comment or the
discussion in the Phab review for future improvements in this implementation
(don't use the data layout at all).
There are no regression test changes from this difference, and I'm not sure how to
expose it via a test. I think we actually do want to provide the 'Fast' param when
checking this from DAGCombiner::MergeConsecutiveStores(). Ie, we shouldn't merge
stores if the new stores are not going to be fast. But that change will require
fixing allowsMisalignedMemoryAccess() overrides as noted in D10662.
Differential Revision: http://reviews.llvm.org/D10905
llvm-svn: 243549
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 0396736..a253faa 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -727,14 +727,12 @@
case TargetLowering::Legal: {
// If this is an unaligned store and the target doesn't support it,
// expand it.
+ EVT MemVT = ST->getMemoryVT();
unsigned AS = ST->getAddressSpace();
unsigned Align = ST->getAlignment();
- if (!TLI.allowsMisalignedMemoryAccesses(ST->getMemoryVT(), AS, Align)) {
- Type *Ty = ST->getMemoryVT().getTypeForEVT(*DAG.getContext());
- unsigned ABIAlignment = DAG.getDataLayout().getABITypeAlignment(Ty);
- if (Align < ABIAlignment)
- ExpandUnalignedStore(cast<StoreSDNode>(Node), DAG, TLI, this);
- }
+ const DataLayout &DL = DAG.getDataLayout();
+ if (!TLI.allowsMemoryAccess(*DAG.getContext(), DL, MemVT, AS, Align))
+ ExpandUnalignedStore(cast<StoreSDNode>(Node), DAG, TLI, this);
break;
}
case TargetLowering::Custom: {
@@ -842,16 +840,13 @@
StVT.getSimpleVT())) {
default: llvm_unreachable("This action is not supported yet!");
case TargetLowering::Legal: {
+ EVT MemVT = ST->getMemoryVT();
unsigned AS = ST->getAddressSpace();
unsigned Align = ST->getAlignment();
// If this is an unaligned store and the target doesn't support it,
// expand it.
- if (!TLI.allowsMisalignedMemoryAccesses(ST->getMemoryVT(), AS, Align)) {
- Type *Ty = ST->getMemoryVT().getTypeForEVT(*DAG.getContext());
- unsigned ABIAlignment = DL.getABITypeAlignment(Ty);
- if (Align < ABIAlignment)
- ExpandUnalignedStore(cast<StoreSDNode>(Node), DAG, TLI, this);
- }
+ if (!TLI.allowsMemoryAccess(*DAG.getContext(), DL, MemVT, AS, Align))
+ ExpandUnalignedStore(cast<StoreSDNode>(Node), DAG, TLI, this);
break;
}
case TargetLowering::Custom: {
@@ -894,17 +889,14 @@
switch (TLI.getOperationAction(Node->getOpcode(), VT)) {
default: llvm_unreachable("This action is not supported yet!");
case TargetLowering::Legal: {
+ EVT MemVT = LD->getMemoryVT();
unsigned AS = LD->getAddressSpace();
unsigned Align = LD->getAlignment();
+ const DataLayout &DL = DAG.getDataLayout();
// If this is an unaligned load and the target doesn't support it,
// expand it.
- if (!TLI.allowsMisalignedMemoryAccesses(LD->getMemoryVT(), AS, Align)) {
- Type *Ty = LD->getMemoryVT().getTypeForEVT(*DAG.getContext());
- unsigned ABIAlignment = DAG.getDataLayout().getABITypeAlignment(Ty);
- if (Align < ABIAlignment){
- ExpandUnalignedLoad(cast<LoadSDNode>(Node), DAG, TLI, RVal, RChain);
- }
- }
+ if (!TLI.allowsMemoryAccess(*DAG.getContext(), DL, MemVT, AS, Align))
+ ExpandUnalignedLoad(cast<LoadSDNode>(Node), DAG, TLI, RVal, RChain);
break;
}
case TargetLowering::Custom: {
@@ -1091,18 +1083,14 @@
Chain = Res.getValue(1);
}
} else {
- // If this is an unaligned load and the target doesn't support
- // it, expand it.
+ // If this is an unaligned load and the target doesn't support it,
+ // expand it.
EVT MemVT = LD->getMemoryVT();
unsigned AS = LD->getAddressSpace();
unsigned Align = LD->getAlignment();
- if (!TLI.allowsMisalignedMemoryAccesses(MemVT, AS, Align)) {
- Type *Ty = LD->getMemoryVT().getTypeForEVT(*DAG.getContext());
- unsigned ABIAlignment = DAG.getDataLayout().getABITypeAlignment(Ty);
- if (Align < ABIAlignment){
- ExpandUnalignedLoad(cast<LoadSDNode>(Node), DAG, TLI, Value, Chain);
- }
- }
+ const DataLayout &DL = DAG.getDataLayout();
+ if (!TLI.allowsMemoryAccess(*DAG.getContext(), DL, MemVT, AS, Align))
+ ExpandUnalignedLoad(cast<LoadSDNode>(Node), DAG, TLI, Value, Chain);
}
break;
}