Fix a bug in DAGCombiner::MatchBSwapHWord. Make sure the node has operands before referencing them. rdar://12868039

llvm-svn: 170078

2 files changed, 48 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 893cf2036a4..7c54d17275a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -2984,7 +2984,8 @@ SDValue DAGCombiner::MatchBSwapHWord(SDNode *N, SDValue N0, SDValue N1) {
   SDValue N00 = N0.getOperand(0);
   SDValue N01 = N0.getOperand(1);
 
-  if (N1.getOpcode() == ISD::OR) {
+  if (N1.getOpcode() == ISD::OR &&
+      N00.getNumOperands() == 2 && N01.getNumOperands() == 2) {
     // (or (or (and), (and)), (or (and), (and)))
     SDValue N000 = N00.getOperand(0);
     if (!isBSwapHWordElement(N000, Parts))
diff --git a/llvm/test/CodeGen/X86/2012-12-12-DAGCombineCrash.ll b/llvm/test/CodeGen/X86/2012-12-12-DAGCombineCrash.ll
new file mode 100644
index 00000000000..8cef2c8201c
--- /dev/null
+++ b/llvm/test/CodeGen/X86/2012-12-12-DAGCombineCrash.ll
@@ -0,0 +1,46 @@
+; RUN: llc -march=x86 -mtriple=i686-apple-ios -mcpu=yonah < %s
+; rdar://12868039
+
+define void @t() nounwind ssp {
+  %1 = alloca i32
+  %2 = ptrtoint i32* %1 to i32
+  br label %3
+
+; <label>:3                                       ; preds = %5, %3, %0
+  switch i32 undef, label %3 [
+    i32 611946160, label %5
+    i32 954117870, label %4
+  ]
+
+; <label>:4                                       ; preds = %3
+  ret void
+
+; <label>:5                                       ; preds = %5, %3
+  %6 = add i32 0, 148
+  %7 = and i32 %6, 48
+  %8 = add i32 %7, 0
+  %9 = or i32 %2, %8
+  %10 = xor i32 -1, %2
+  %11 = or i32 %8, %10
+  %12 = or i32 %9, %11
+  %13 = xor i32 %9, %11
+  %14 = sub i32 %12, %13
+  %15 = xor i32 2044674005, %14
+  %16 = xor i32 %15, 0
+  %17 = shl nuw nsw i32 %16, 1
+  %18 = sub i32 0, %17
+  %19 = and i32 %18, 2051242402
+  %20 = sub i32 0, %19
+  %21 = xor i32 %20, 0
+  %22 = xor i32 %21, 0
+  %23 = add i32 0, %22
+  %24 = shl i32 %23, 1
+  %25 = or i32 1, %24
+  %26 = add i32 0, %25
+  %27 = trunc i32 %26 to i8
+  %28 = xor i8 %27, 125
+  %29 = add i8 %28, -16
+  %30 = add i8 0, %29
+  store i8 %30, i8* null
+  br i1 undef, label %5, label %3
+}