[llvm] r335787 - [X86] In X86DAGToDAGISel::PreprocessISelDAG, make sure we don't access N after we delete it.

[Craig Topper via llvm-commits]

Author: ctopper
Date: Wed Jun 27 13:58:46 2018
New Revision: 335787

URL: http://llvm.org/viewvc/llvm-project?rev=335787&view=rev
Log:
[X86] In X86DAGToDAGISel::PreprocessISelDAG, make sure we don't access N after we delete it.

If we turn X86ISD::AND into ISD::AND, we delete N. But we were continuing onto the next block of code even though N no longer existed.

Just happened to notice it. I assume asan didn't notice it because we explicitly unpoison deleted nodes and give them a DELETE_NODE opcode.

Modified:
    llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp

Modified: llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp?rev=335787&r1=335786&r2=335787&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp Wed Jun 27 13:58:46 2018
@@ -668,6 +668,7 @@ void X86DAGToDAGISel::PreprocessISelDAG(
       CurDAG->ReplaceAllUsesOfValueWith(SDValue(N, 0), Res);
       ++I;
       CurDAG->DeleteNode(N);
+      continue;
     }
 
     if (OptLevel != CodeGenOpt::None &&