Improve a few comments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46217 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/StrongPHIElimination.cpp b/lib/CodeGen/StrongPHIElimination.cpp
index e5cae2b..ff58e79 100644
--- a/lib/CodeGen/StrongPHIElimination.cpp
+++ b/lib/CodeGen/StrongPHIElimination.cpp
@@ -550,7 +550,9 @@
for (DomForestNode::iterator CI = DFNode->begin(), CE = DFNode->end();
CI != CE; ++CI) {
DomForestNode* child = *CI;
-
+
+ // If the current node is live-out of the defining block of one of its
+ // children, insert a copy for it
if (isLiveOut(DFNode->getReg(),
MRI.getVRegDef(child->getReg())->getParent(), MRI, LV)) {
// Insert copies for parent
@@ -565,6 +567,9 @@
PHIUnion.erase(SrcReg);
}
}
+
+ // If a node is live-in to the defining block of one of its children, but
+ // not live-out, then we need to scan that block for local interferences.
} else if (isLiveIn(DFNode->getReg(),
MRI.getVRegDef(child->getReg())->getParent(),
MRI, LV) ||