Codegen factor nodes more intelligently according to perceived register pressure.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19532 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelPattern.cpp b/lib/Target/X86/X86ISelPattern.cpp
index d5ec466..d13dbdf 100644
--- a/lib/Target/X86/X86ISelPattern.cpp
+++ b/lib/Target/X86/X86ISelPattern.cpp
@@ -2088,8 +2088,20 @@
assert(0 && "Node not handled yet!");
case ISD::EntryToken: return; // Noop
case ISD::TokenFactor:
- for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i)
- Select(Node->getOperand(i));
+ if (Node->getNumOperands() == 2) {
+ bool OneFirst =
+ getRegPressure(Node->getOperand(1))>getRegPressure(Node->getOperand(0));
+ Select(Node->getOperand(OneFirst));
+ Select(Node->getOperand(!OneFirst));
+ } else {
+ std::vector<std::pair<unsigned, unsigned> > OpsP;
+ for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i)
+ OpsP.push_back(std::make_pair(getRegPressure(Node->getOperand(i)), i));
+ std::sort(OpsP.begin(), OpsP.end());
+ std::reverse(OpsP.begin(), OpsP.end());
+ for (unsigned i = 0, e = Node->getNumOperands(); i != e; ++i)
+ Select(Node->getOperand(OpsP[i].second));
+ }
return;
case ISD::CopyToReg:
if (getRegPressure(N.getOperand(0)) > getRegPressure(N.getOperand(1))) {