[PATCH] D47437: [PowerPC] Fix the incorrect iterator inside peephole

[Qing Shan Zhang via Phabricator via llvm-commits]

steven.zhang created this revision.
steven.zhang added a reviewer: hfinkel.
Herald added subscribers: kbarton, hiraditya.

Instruction selection will insert nodes into the underlying list after the root node and iterating will thereby miss it. We should NOT assume that, the root node is the last element in the DAG nodelist.


https://reviews.llvm.org/D47437

Files:
  llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
  llvm/test/CodeGen/PowerPC/ppcf128-endian.ll


Index: llvm/test/CodeGen/PowerPC/ppcf128-endian.ll
===================================================================
--- llvm/test/CodeGen/PowerPC/ppcf128-endian.ll
+++ llvm/test/CodeGen/PowerPC/ppcf128-endian.ll
@@ -43,10 +43,10 @@
 ; CHECK: .LCPI[[LC]]_1:
 ; CHECK: .long   0
 ; CHECK: @caller_const
-; CHECK: addi [[REG0:[0-9]+]], {{[0-9]+}}, .LCPI[[LC]]_0
-; CHECK: addi [[REG1:[0-9]+]], {{[0-9]+}}, .LCPI[[LC]]_1
-; CHECK: lfs 1, 0([[REG0]])
-; CHECK: lfs 2, 0([[REG1]])
+; CHECK: addis [[REG0:[0-9]+]], 2, .LCPI[[LC]]_0 at toc@ha
+; CHECK: addis [[REG1:[0-9]+]], 2, .LCPI[[LC]]_1 at toc@ha
+; CHECK: lfs 1, .LCPI[[LC]]_0 at toc@l([[REG0]])
+; CHECK: lfs 2, .LCPI[[LC]]_1 at toc@l([[REG1]])
 ; CHECK: bl test
 
 define ppc_fp128 @result() {
Index: llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
===================================================================
--- llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ 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;


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