[PowerPC] Fix the incorrect iterator inside peephole
Instruction selection can insert nodes into the underlying list after the root
node so iterating will thereby miss it. We should NOT assume that, the root node
is the last element in the DAG nodelist.
Patch by: steven.zhang (Qing Shan Zhang)
Differential Revision: https://reviews.llvm.org/D47437
llvm-svn: 333415
diff --git a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index 518defe..067215a 100644
--- a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -5169,8 +5169,7 @@
}
void PPCDAGToDAGISel::PreprocessISelDAG() {
- SelectionDAG::allnodes_iterator Position(CurDAG->getRoot().getNode());
- ++Position;
+ SelectionDAG::allnodes_iterator Position = CurDAG->allnodes_end();
bool MadeChange = false;
while (Position != CurDAG->allnodes_begin()) {
@@ -5858,8 +5857,7 @@
// unnecessary. When that happens, we remove it here, and redefine the
// relevant 32-bit operation to be a 64-bit operation.
- SelectionDAG::allnodes_iterator Position(CurDAG->getRoot().getNode());
- ++Position;
+ SelectionDAG::allnodes_iterator Position = CurDAG->allnodes_end();
bool MadeChange = false;
while (Position != CurDAG->allnodes_begin()) {
@@ -6016,8 +6014,7 @@
if (PPCSubTarget->isDarwin() || !PPCSubTarget->isPPC64())
return;
- SelectionDAG::allnodes_iterator Position(CurDAG->getRoot().getNode());
- ++Position;
+ SelectionDAG::allnodes_iterator Position = CurDAG->allnodes_end();
while (Position != CurDAG->allnodes_begin()) {
SDNode *N = &*--Position;