RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-24 19:52:54 +01:00
Code Issues Projects Releases Wiki Activity

* Only turn a load to UNDEF if all of its outputs have no uses (indexed loads

Browse Source 
produce two results.)
* Do not touch volatile loads.

llvm-svn: 36604
This commit is contained in:
Evan Cheng 2007-05-01 00:38:21 +00:00
parent 799da3f145
commit fe933cd6ca
1 changed files with 20 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -3326,11 +3326,26 @@ SDOperand DAGCombiner::visitLOAD(SDNode *N) {
LoadSDNode *LD = cast<LoadSDNode>(N);
SDOperand Chain = LD->getChain();
SDOperand Ptr = LD->getBasePtr();
// If there are no uses of the loaded value, change uses of the chain value
// into uses of the chain input (i.e. delete the dead load).
if (N->hasNUsesOfValue(0, 0))
return CombineTo(N, DAG.getNode(ISD::UNDEF, N->getValueType(0)), Chain);
// If load is not volatile and there are no uses of the loaded value (and
// the updated indexed value in case of indexed loads), change uses of the
// chain value into uses of the chain input (i.e. delete the dead load).
if (!LD->isVolatile()) {
bool HasUses = false;
SmallVector<MVT::ValueType, 2> VTs;
for (unsigned i = 0, e = N->getNumValues(); i != e; ++i) {
if (!N->hasNUsesOfValue(0, i)) {
HasUses = true;
break;
}
VTs.push_back(N->getValueType(i));
}
if (!HasUses) {
SmallVector<SDOperand, 1> Ops;
return CombineTo(N, DAG.getNode(ISD::UNDEF, &VTs[0], VTs.size(), 0, 0),
Chain);
}
}
// If this load is directly stored, replace the load value with the stored
// value.