[llvm] r178429 - DAGCombine: visitXOR can replace a node without returning it, bail out in that case.

[Benjamin Kramer]

Author: d0k
Date: Sat Mar 30 16:28:18 2013
New Revision: 178429

URL: http://llvm.org/viewvc/llvm-project?rev=178429&view=rev
Log:
DAGCombine: visitXOR can replace a node without returning it, bail out in that case.

Fixes the crash reported in PR15608.

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    llvm/trunk/test/CodeGen/X86/2013-01-09-DAGCombineBug.ll

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=178429&r1=178428&r2=178429&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Sat Mar 30 16:28:18 2013
@@ -6823,9 +6823,9 @@ SDValue DAGCombiner::visitBRCOND(SDNode
                              MVT::Other, Chain, Tmp, N2);
         }
 
-        // visitXOR has changed XOR's operands.
-        Op0 = TheXor->getOperand(0);
-        Op1 = TheXor->getOperand(1);
+        // visitXOR has changed XOR's operands or replaced the XOR completely,
+        // bail out.
+        return SDValue(N, 0);
       }
     }
 

Modified: llvm/trunk/test/CodeGen/X86/2013-01-09-DAGCombineBug.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/2013-01-09-DAGCombineBug.ll?rev=178429&r1=178428&r2=178429&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/2013-01-09-DAGCombineBug.ll (original)
+++ llvm/trunk/test/CodeGen/X86/2013-01-09-DAGCombineBug.ll Sat Mar 30 16:28:18 2013
@@ -39,3 +39,36 @@ define void @t() nounwind uwtable ssp {
 ; <label>:11                                      ; preds = %11, %4
   br label %11
 }
+
+; PR15608
+ at global = external constant [2 x i8]
+
+define void @PR15608() {
+bb:
+  br label %bb3
+
+bb1:                                              ; No predecessors!
+  br i1 icmp ult (i64 xor (i64 zext (i1 trunc (i192 lshr (i192 or (i192 shl (i192 zext (i64 trunc (i128 lshr (i128 trunc (i384 lshr (i384 or (i384 shl (i384 zext (i64 ptrtoint ([2 x i8]* @global to i64) to i384), i384 192), i384 425269881901436522087161771558896140289), i384 128) to i128), i128 64) to i64) to i192), i192 64), i192 1), i192 128) to i1) to i64), i64 1), i64 1), label %bb2, label %bb3
+
+bb2:                                              ; preds = %bb1
+  unreachable
+
+bb3:                                              ; preds = %bb1, %bb
+  br i1 xor (i1 trunc (i192 lshr (i192 or (i192 shl (i192 zext (i64 trunc (i128 lshr (i128 trunc (i384 lshr (i384 or (i384 shl (i384 zext (i64 ptrtoint ([2 x i8]* @global to i64) to i384), i384 192), i384 425269881901436522087161771558896140289), i384 128) to i128), i128 64) to i64) to i192), i192 64), i192 1), i192 128) to i1), i1 trunc (i192 lshr (i192 or (i192 and (i192 or (i192 shl (i192 zext (i64 trunc (i128 lshr (i128 trunc (i384 lshr (i384 or (i384 shl (i384 zext (i64 ptrtoint ([2 x i8]* @global to i64) to i384), i384 192), i384 425269881901436522087161771558896140289), i384 128) to i128), i128 64) to i64) to i192), i192 64), i192 1), i192 -340282366920938463463374607431768211457), i192 shl (i192 zext (i1 trunc (i192 lshr (i192 or (i192 shl (i192 zext (i64 trunc (i128 lshr (i128 trunc (i384 lshr (i384 or (i384 shl (i384 zext (i64 ptrtoint ([2 x i8]* @global to i64) to i384), i384 192), i384 425269881901436522087161771558896140289), i384 128) to i128), i128 64) to i64!
 ) to i192
 ), i192 64), i192 1), i192 128) to i1) to i192), i192 128)), i192 128) to i1)), label %bb7, label %bb4
+
+bb4:                                              ; preds = %bb6, %bb3
+  %tmp = phi i1 [ true, %bb6 ], [ trunc (i192 lshr (i192 or (i192 and (i192 or (i192 shl (i192 zext (i64 trunc (i128 lshr (i128 trunc (i384 lshr (i384 or (i384 shl (i384 zext (i64 ptrtoint ([2 x i8]* @global to i64) to i384), i384 192), i384 425269881901436522087161771558896140289), i384 128) to i128), i128 64) to i64) to i192), i192 64), i192 1), i192 -340282366920938463463374607431768211457), i192 shl (i192 zext (i1 trunc (i192 lshr (i192 or (i192 shl (i192 zext (i64 trunc (i128 lshr (i128 trunc (i384 lshr (i384 or (i384 shl (i384 zext (i64 ptrtoint ([2 x i8]* @global to i64) to i384), i384 192), i384 425269881901436522087161771558896140289), i384 128) to i128), i128 64) to i64) to i192), i192 64), i192 1), i192 128) to i1) to i192), i192 128)), i192 128) to i1), %bb3 ]
+  br i1 false, label %bb8, label %bb5
+
+bb5:                                              ; preds = %bb4
+  br i1 %tmp, label %bb8, label %bb6
+
+bb6:                                              ; preds = %bb5
+  br i1 false, label %bb8, label %bb4
+
+bb7:                                              ; preds = %bb3
+  unreachable
+
+bb8:                                              ; preds = %bb6, %bb5, %bb4
+  unreachable
+}